Master Thesis Topics

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All | Physics | Chemistry | Biology | Electronics | Materials | Mechatronics | Medicine


Promotor

All | Andre Stesmans | Andre Vantomme | Arnout Ceulemans | Carmen Bartic | Chris Van Haesendonck | Christ Glorieux | Dominiek Reynaerts | Guy Vandenbosch | Herbert De Gersem | Jan Vermant | Jean-Pierre Locquet | Jeroen Lammertyn | Jin Won Seo | Johan Martens | Koen Clays | Kristiaan Temst | Margriet Van Bael | Mark Van der Auweraer | Michel Houssa | Paolo Pescarmona | Peter Lievens | Robert Puers | Steven De Feyter | Thierry Verbiest | Victor Moshchalkov


Master Thesis Topics


Magnetoelectric properties of oxide heterostructures
Context: In many applications of magnetic materials – as in hard disk storage – applying a large magnetic field is needed to perform the reversal of the magnetization from one state to the other. However the application of a large magnetic field required the integration of bulky electromagnets that cannot be scaled down easily.

A potential remedy to this challenge is offered through the use of magnetoelectric materials. In such compounds there is a coupling between the magnetic spins and the electric dipoles such that the application of an electric field can lead to a reversal of the magnetization. And vice versa, the application of a magnetic field can lead to the appearance of a ferroelectric dipole moment. Unfortunately for most known compounds this coupling is rather weak leading to small magnetoelectric coefficients. In this project the goal is to explore the magnetoelectric properties of oxide heterostructures that consist of alternating and well-known ferroelectric (like BaTiO3) and ferromagnetic (like LaMnO3) layers as illustrated in the adjacent Figure.

Objective: Determine the magnetoelectric properties of oxide heterostructures consisting of ferroelectric and ferromagnetic layers.

Work to be done: Select the appropriate ferroelectric and ferromagnetic materials. Grow thin films of each material and measure its structural and physical properties. Next synthesize the heterostructures and measure its structural and magnetoelectric properties.

Expected results: Demonstrate whether in layered heterostructures of ferroelectric and ferromagnetic materials a significant magnetoelectric coupling can appear.




Promotor : Jean-Pierre Locquet
Faculty/research group :
Daily supervision : Kabir Bhuyian, Mariela Menghini
Graduating option :
Type of work : Experimental
Number of students : 1

First-principles modeling of high-mobility semiconductors/insulator interface
A next step in boosting progress and performance of semiconductor devices implies, in replacement of the current Si, incorporation of semiconductors of higher intrinsic carrier mobility. When introduced at the nano scale, this will require new analysis and physics insight. Understanding the fundamental properties of such gate stacks is important in order to understand their behavior in devices.

The work to be performed encompasses computation and modeling the structural and electronic properties of interfaces of high-mobility semiconductors (e.g., Ge) with high-quality metal oxide insulators, based on density functional theory.

As a propelling tool, the results will be correlated, when possible, to experimental results obtained through structural and electrical observations.

This work will be performed in collaboration with IMEC.

Promotor : Michel Houssa
Faculty/research group : Sciences/Department of Physics/Semiconductor Physics Section
Daily supervision : M. Houssa, M. Scarozza
Graduating option : Science/Nanoscience or Engineering/Nanotechnology
Type of work : Experimental
Number of students : 1

Superconductivity in Diamond films: doping effects induced by chemical substitution and electric gate field
Although diamond has always been adored as a jewel, it shows even more fascinating physical properties; it is the hardest material ever known, it has the highest thermal conductivity at room temperature and in its pure form it can withstand very high electrical fields. When charge carriers are introduced in diamond, e.g. by chemical doping with Boron (B), the C1-xBx diamond:B can exhibit an insulator-to-metal transition (pMott ~2 1020 cm-3 ). Diamond with moderate boron doping (p~1017-1019 cm-3) becomes a p-type semiconductor, with boron acting as an acceptor. In this form, it is a promising material for electrical applications, such as high frequency and high power devices, because of its high breakdown field (>10MV/cm) and high carrier mobility. Heavily doped boron-diamond shows metallic conduction, and even more, C1-xBx becomes superconducting, with relatively high critical temperatures Tc. This project will concentrate on studying the superconducting properties of this heavily doped diamond.

Promotor : Victor Moshchalkov
Faculty/research group : Science/INPAC
Daily supervision : Gufei Zhang, Johan Vanacken
Graduating option : Science/Nanoscience or Engineering/Nanotechnology
Type of work : experimental
Number of students : 1

Plasmon enhanced photoluminescence in quantum-dot coatings
The shrinking of component size in nanoelectronics (Moore's law) has encountered the physical limits of electronic transport, affecting potential future technological progresses. The most promising solution here is to go for optical intra- and inter-chip interconnects, which are much faster than conventional metallic interconnects. The issue is then to be able to manipulate photons in the sub wavelength scale, i.e. the nanometric scale. Remarkably, in that limit nanomodulated metallic films can combine the better of the two worlds: surface plasmons in these films can very efficiently enable the light propagation, together with the still efficient electrical conductivity, allowing to reach superlensing, cloaking, unusual-non-linear effects or luminescence amplification nano-emitters. The study of these phenomena in special designed nanostructures (together with IMEC) is done via UV to NIR optical spectroscopy / photoluminescence in pulsed magnetic fields.

Promotor : Victor Moshchalkov
Faculty/research group : Science/INPAC
Daily supervision : Thomas Nuytten, Johan Vanacken
Graduating option : Science/Nanoscience or Engineering/Nanotechnology
Type of work : experimental
Number of students : 1

Molecular Magnets
Probing the nanoscale world is often performed through mesoscopic systems that provide a bridge to our macroscopic world. In the field of magnetism, one can find such mesoscopic systems in the form of molecular magnets. In general these nanoscale clusters provide a high spin ground state, f.e. S=10 for the prototype molecular magnet Mangenese-12 Acetate (Mn12Ac), in combination with superparamagnetic behavior when grown into single crystals. The result is a set of mesoscopic systems that show intrinsically quantum mechanical processes, such as Quantum Tunneling of the Magnetization (QTM), Quantum Magnetic Deflagration and many more, in studies of the magnetization of millimetre-size single crystals. Our lab focuses on the behaviour of such molecular magnets when exposed to highly non-adiabatic conditions in pulsed magnetic fields.

Promotor : Victor Moshchalkov
Faculty/research group : Science/INPAC
Daily supervision : Wim Decelle, Johan Vanacken
Graduating option : Science/Nanoscience or Engineering/Nanotechnology
Type of work : experimental
Number of students : 1

Characterization of Functionalized Magnetic Nanoparticles for Medical Diagnostics and Treatments
This research aims to develop magnetic nanoparticle crystals with physicochemical properties tailored for in vivo diagnostic MR imaging and cell tracking following the exvivo labeling of cells. Desirable properties from such nanoparticles are stronger signal intensity using a smaller number of particles, better and more specific cellular uptake, the potential to be utilized for quantification and non-toxicity, improved specificity and stability in time. Such requirements can be met by tuning the magnetic composition, the physical size and geometry, the chemical and biofunctional coatings, polymeric/silica based core-shell thickness and/or lipidic coating techniques which are developed at IMEC. Such nanoparticle development effort also requires co-development of analytical techniques to assess the properties of these novel materials..
To reach the above objectives, we need to develop diagnostic magnetic nanoparticle imaging/tracking methods to reach high sensitivity and specificity. Whereas current MRI diagnostic imaging techniques are optimized to provide maximal tissue contrast, the same instruments can be tuned to be sensitive towards information on the magnetic particles. Such imaging method can be used for sensitive stem cell tracking.
The particular task of the thesis student consists out of the magnetic characterization of these nanoparticles. This will be done by VSM (vibrating sample magnetometer), SQUID (Superconducting Quantum Interference Device), Scanning Hal probe and Magnetic Force Microscope. Furthermore structural experiments will be done using X-ray, TEM and synchrotron techniques.
This subject is multidisciplinary and will allow the student to get into contact with several other important scientific and medical disciplines

Promotor : Victor Moshchalkov
Faculty/research group : Science/INPAC
Daily supervision : Nele Schildermans, Johan Vanacken
Graduating option : Science/Nanoscience or Engineering/Nanotechnology
Type of work : experimental
Number of students : 1

Confined condensate and flux in mesoscopic two-gap superconductors
The recent discovery of two-gap superconductivity in MgB2 and, especially, in iron pnictides (in February 2008) caused a burst of research of these novel superconductors. Their moderately high critical temperature and very high critical field present great potential for applications, while the two-band phenomenology opens a whole exploration avenue in fundamental physics.

The project aims at a theoretical investigation of the effects of quantum confinement in mesoscopic two-gap superconductors, mainly on the flux enclosure (vortex matter) and the transport and dynamic properties of the two coupled electronic condensates. This is a very promising and completely unexplored research domain, where several new physical effects are expected to emerge. For example, new types of thermodynamically stable vortex phases are envisaged, as well as the transport features beyond known single-gap effects. In addition, successful realization of our project will offer ways to enhance the critical field and current via the controlled nanostructuring of novel superconductors, which is of primary importance for their practical applications.

Promotor : Victor Moshchalkov
Faculty/research group : Faculty of Science/Dept Chemistry and Physics
Daily supervision : Vu Hung Dao, Erwin Lijnen
Graduating option : Science/Nanoscience or Engineering/Nanotechnology
Type of work : theoretical, simulations
Number of students : 1

Superconducting nanoparticles
On the doorstep of its 100th anniversary, superconductivity in simple bulk materials is well understood and knows many technological applications. Surprisingly, superconductivity can even exist in objects that are smaller than the size of a Cooper pair (electron pairs responsible for superconductivity). An intriguing fundamental question is if and how superconductivity can exist in systems of only a few nm in size. Such nano-particles have distinct size dependent superconducting properties and can moreover be used as building blocks in nanogranular materials with interesting new behaviour.
In this project, we will produce nanoparticles of superconducting materials (e.g. Pb). Such nanosystems can be made by cluster deposition, i.e. producing clusters of atoms and depositing them on a substrate, or by implantation of Pb ions into a Si layer which will precipitate to form nanoparticles in a Si matrix. We will investigate the influence of the production parameters on the formation process of the nanoparticles. The superconducting properties of ensembles of these nano-particles will be investigated by SQUID magnetometry and electrical transport measurements at low temperatures.



Promotor : Margriet Van Bael
Faculty/research group : Faculty of Science/Department of Physics and Astronomy
Daily supervision : Jo Cuppens, Huan Wang
Graduating option : Science/Nanoscience or Engineering/Nanotechnology
Type of work : experimental
Number of students : 2

Growth of nanostructures by self assembly via low angle deposition
Self-assembly has become a valuable technique for the production of nanostructures: nanometer sized islands are produced by the controlled deposition of an atomic beam on a substrate in ultra high vacuum (UHV). In this research project, we would like to explore a recent development in self-assembly, namely the growth of nanostructures that form when the atomic beam is deposited at a very small incident angle with respect to the substrate (glancing angle deposition). The strong self-shadowing effects result in a specific growth mode in which the material preferentially grows on top of the existing precipitates. This way, instead of a continuous two-dimensional layer, structures of separate pillars (10 to several 100 nm wide) are formed, also called sculptured thin films. You will learn to operate the UHV deposition setup and you will characterize the structure of the resulting samples by atomic force microscopy (AFM) and electron microscopy (SEM). We will also study the magnetic properties and specifically the strong anisotropy of Co-nanowires formed in this way.



Promotor : Margriet Van Bael
Faculty/research group : Faculty of Science/Department of Physics and Astronomy
Daily supervision : Anupam Sharma, Kenneth Ugochukwu
Graduating option : Science/Nanoscience or Engineering/Nanotechnology
Type of work : Experimental
Number of students : 2

Amyloid fibrils as a template for the growth of metallic nanowires
Apart from their normal, native configuration proteins can adopt an alternative highly organized state commonly known as an amyloid fibril. While the formation of these protein aggregates can be linked to various diseases, the self-assembled wires of biomolecules can also be used as templates for the preparation of metallic nanowires that can serve as building blocks for nanoelectronics.
The purpose of this thesis work is to control the growth of insulin fibrils having a length of several micrometers and a diameter of only a few nanometers. The fibrils, which are deposited from the liquid onto a properly functionalized substrate, can then be metallized by covering the fibrils with metallic nanoparticles that are obtained by adding a metallic containing salt to the liquid. Finally, the electrical properties of the metallic nanowires can be probed by electrostatic force microscopy complemented by frequency-dependent measurements of the impedance and by optical circular dichroism spectroscopy.

Promotor : Chris Van Haesendonck
Faculty/research group : Faculty of Science/Department of Physics and Astronomy
Daily supervision : Johan Snauwaert
Graduating option : Science/Nanoscience or Engineering/Nanotechnology
Type of work : experimental
Number of students : 2

Probing the magneto-electrical properties with scanning probes
For your master thesis you will investigate thin films of complex oxides that reveal at the same time ferroelectric and ferromagnetic order. The coupling between both order parameters in these so-called magneto-electrical materials allows to control the ferromagnetic domain structure by applying an electrical field. You will determine this coupling using scanning probes that are able to detect with nanometer resolution both the ferroelectric and the magnetic response. The samples under investigation are thin films of multifunctional metal oxide materials that are obtained by co-deposition of the metallic components in a reactive oxygen atmosphere.

Promotor : Chris Van Haesendonck
Faculty/research group : Faculty of Science/Department of Physics and Astronomy
Daily supervision : Danying Li, Alexander Volodin
Graduating option : Science/Nanoscience or Engineering/Nanotechnology
Type of work : experimental
Number of students : 2

Electronic and magnetic properties of self-organized Co islands
For your thesis work you aim at studying the size and shape dependence of the electronic and magnetic properties of very small ferromagnetic Co islands on the surface of a cleaved semiconductor single crystal. Quantum-mechanical confinement effects strongly affect the island properties because of the nanometer size of the islands. The islands are obtained by Co atom deposition and subsequent self-organization of the deposited atoms. For studying the properties of the islands you rely on scanning tunneling microscopy (STM) and scanning tunneling spectroscopy (STS) in ultra-high vacuum. In particular, you will also use spin-polarized STS measurements that are able to resolve with atomic resolution the magnetism of the Co islands. This magnetism is strongly affected by the interaction between adjacent Co islands via the doped semiconductor substrate.

Promotor : Chris Van Haesendonck
Faculty/research group : Faculty of Science/Department of Physics and Astronomy
Daily supervision : Koen Schouteden
Graduating option : Science/Nanoscience or Engineering/Nanotechnology
Type of work : Experimental
Number of students : 2

The electromechanical properties of two-dimensional graphene flakes
Recently, it became possible to isolate individual atomic layers of carbon from a graphite crystal. These so-called graphene layers have unique two-dimensional electrical transport properties as well as remarkable mechanical characteristics that you will investigate in the framework of your master thesis. In particular, you will study how the electrical conduction process can be modulated by local mechanical deformation or electrical disturbance of suspended graphene flakes with the tip of a scanning force microscope. Suspended graphene layers are obtained by positioning the graphene flakes above holes in the substrate that are created by combining electron beam lithography and etching of the substrate.

Promotor : Chris Van Haesendonck
Faculty/research group : Science/Department of Physics and Astronomy
Daily supervision : Tom Moorkens, Fengqi Song, Alexander Volodin
Graduating option : Science/Nanoscience or Engineering/Nanotechnology
Type of work : experimental
Number of students : 2

The electromechanical properties of ZnO nanowires
Oxide based semiconductors and in particular ZnO based materials with wide band gap offer unique possibilities for applications in electronic devices due to their remarkable electronic, optical and optoelectronic characteristics. The application potential is further increased by considering ZnO nanowires, where the strongly reduced dimensions give rise to pronounced quantum confinement effects that allow a further tailoring of the physical properties.

For your master thesis you will probe the electronic properties of individual ZnO wires using a combination of electrostatic force microscopy (EFM) and scanning gate microscopy (SGM). Such microscopy requires to first attach electrical contacts to individual ZnO nanowires using electron beam lithograph. With EFM you will then be able to measure the electrical potential distribution in a current-carrying nanowire. On the other hand, with the conductive EFM tip acting as a gate electrode, it is possible to induce a controllable local potential perturbation and to obtain an SGM image of the nanowire.

Promotor : Chris Van Haesendonck
Faculty/research group : Faculty of Science/Department of Physics and Astronomy
Daily supervision : Yujia Zeng, Alexander Volodin
Graduating option : Science/Nanoscience or Engineering/Nanotechnology
Type of work : experimental
Number of students : 2

Cooperative effects in nanoobjects deposited on metal surfaces
Understanding the electronic properties of nano-objects (self-assembled metal islands, deposited metal clusters and closed-packed layers of organic molecules and magnetic adatoms) deposited on various surfaces is a major research challenge in modern nanoscience. In all envisaged applications for new materials and devices, the nano-objects are supposed to be spaced closely enough, so that electronic interactions between them are always induced. It is therefore indispensable to understand and predict the cooperative effects of these interactions. The goal of the present project will be the theoretical investigation of electronic communication¯ between different nano-objects deposited on a metal surface. The effect of this interaction on the electronic surface states, surface magnetization and optical response will be assessed.

Promotor : Chris Van Haesendonck
Faculty/research group : Faculty of Science/Dept Chemistry and Physics
Daily supervision : Erwin Lijnen, Willem Van den Heuvel
Graduating option : Science/Nanoscience or Engineering/Nanotechnology
Type of work : theoretical
Number of students : 1

Embedded semiconductor nanoparticles characterized by electron spin resonance
Part of the enhanced attention paid to solid state nanoparticles derives from the interest in the study of changing fundamental properties of solids when size is reduced down to the nanoscale. A separate class concerns semiconductor nanoparticles embedded in dielectrics, particularly studied for interesting properties, such as remarkable photoluminescence, and potential for (memory) electronic devices.

In these phenomena, occurring point defects commonly play a crucial role, of fundamental impact, making their characterization, and much hoped for, ultimate identification, main targets. In the current work, electron spin resonance (ESR) is applied as a prime non-destructive technique to attain identification on atomic scale, simultaneously enabling probing of the immediate atomic and structural environment.

Part of the work to be carried out implies assisting in taking ESR data at low temperatures and simulation of relevant parameters to infer relevant parameters. Interpretation on the basis of underlying theories will reveal specific particle properties.

Of current interest are Si and Ge particles embedded in various dielectric matrices, the research being carried within continuous international collaboration. This is done in conjunction with application of electrical studies to infer properties such as charge trapping and altering band structure properties.

Promotor : Andre Stesmans
Faculty/research group : Sciences/Department of Physics/Semiconductor Physics Section
Daily supervision : A. Stesmans, M. Jivanescu, K. Keunen
Graduating option : Science/Nanoscience or Engineering/Nanotechnology
Type of work : Experimental
Number of students : 1

Probing the structural quality of semiconductor/heterostructures using electron spin resonance
When dimensionally downward scaling solid structures from the macro over the microscopic down to the nano (quantum) size, the relative importance of surfaces and interfaces gradually increases, even towards taking an all dominant role: One atomic-size imperfection my imply life or dead for the envisioned functional (physical) property.

The technique of magnetic resonance, applied to electrons (ESR), is the unique tool enabling, besides characterization, identification on true atomic scale of imperfections in fully non-destructive way through sensing the magnetic moment of unpaired electrons.

Part of the work to be performed implies assisting in taking ESR spectra at low temperatures and simulation of observed spectra to infer the relevant parameters.

Actual challenges imply the interfaces in Ge/GeO2/SiO2 and GaAs/oxide entities, where identification of crucial interface traps is envisioned. Other items of interest include a natural defect in SiO2 and a center in near-interfacial Si layers.

Promotor : Andre Stesmans
Faculty/research group : Sciences/Department of Physics/Semiconductor Physics Section
Daily supervision : A. Stesmans, M. Jivanescu, K. Keunen
Graduating option : Science/Nanoscience or Engineering/Nanotechnology
Type of work : Experimental
Number of students : 1

Nanoclusters for biosensor applications
Recent research trends combine physics at the nanometre scale with biological systems such as DNA or proteins. Relevant examples are protein microarrays for the simultaneous detection of many different proteins for early diagnosis of specific diseases. To optimise the density of proteins, a new generation of protein nanoarrays is being developed. A possible route towards dense protein nanoarrays is to use atomic clusters on a surface to immobilise individual proteins. The purpose of this thesis research is to create and optimise patterns of atomic clusters on biocompatible surfaces, which will in a later stage be used to bind individual proteins. You will use a laser vaporization cluster source to produce gold clusters of only a few nanometer in size and deposit them on different surfaces. You will investigate the resulting cluster patterns by scanning tunnelling and atomic force microscopy.



Promotor : Margriet Van Bael
Faculty/research group : Faculty of Science/Department of Physics and Astronomy
Daily supervision : Johan Snauwaert
Graduating option : Science/Nanoscience or Engineering/Nanotechnology or Bioengineering
Type of work : Experimental
Number of students : 2

Zero-energy SIMS
Due to the ongoing scaling of semiconductor structures (Moore's law), the position of dopant atoms which determine the electrical properties of a device becomes more important. Until now, secondary ion mass spectrometry (SIMS) is used to determine these dopant profiles due to its high sensitivity. However, quantitative depth profiles with a high depth resolution (sub-nm) are becoming more and more challenging due to the ion-substrate interaction. Zero-energy SIMS aims at eliminating these drawbacks by replacing the ions by a combination of electrons and a reactive gas mixture, and by ionizing the emitted species by laser post-ionization. First results are very promising. In this thesis subject the technique will be optimized further, with emphasis to the fundamental etching and laser post-ionization mechanisms.



Promotor : Peter Lievens
Faculty/research group : Faculty of Science/Department of Physics and Astronomy
Daily supervision : Nico Vanhove
Graduating option : Science/Nanoscience or Engineering/Nanotechnology
Type of work : experimental
Number of students : 2

Clusters for catalysis
Catalytic technologies are at the core of more than 80 % of the processes in the chemical industry today. Improvement of their performance is expected to have a major impact in the near future in the crucial strategic issues of environment and renewable energy. Most of the catalysts nowadays consist of highly dispersed very small metallic (nano)particles supported on oxide supports. Two key parameters that are directly influencing their performance are the size of the metallic particles and the nature of the support.
We have recently implemented a new physical method of producing very homogeneous model catalysts based on size-selected gas phase clusters. By studying their catalytic properties in collaboration with catalysis groups, we aim at understanding the role of the size and support on the catalytic activity with as ultimate goal the design of novel high performance catalysts. The goal of this thesis research is to produce series of size-selected Au, Pd, and Pt clusters using the laser vaporization cluster source (between few atoms and 4.0 nm) and deposit them onto different types of thin oxide layers. You will characterize these transparent materials by grazing incidence X-ray diffraction and by atomic force and scanning tunneling microscopies (AFM and STM). In a second stage their catalytic activity by fluorescence microscopy detection techniques using reactive fluorescent probe molecules will be monitored.

Promotor : Peter Lievens
Faculty/research group : Faculty of Science/Department of Physics and Astronomy
Daily supervision : Didier Grandjean, Tom Vosch, Christian Romero
Graduating option : Science/Nanoscience or Bio-engineering or Engineering/Nanotechnology
Type of work : experimental
Number of students : 2

Laser spectroscopy and mass spectrometry of doped clusters
How does the composition of doped silicon clusters influence their geometry and electronic structure?

We produce beams of mixed clusters of a few up to several hundreds of atoms with a laser vaporization source, and study their properties with laser spectroscopy and mass spectrometry. With deep infrared spectroscopy we can identify vibrational transitions that are characteristic for the cluster geometry, while visible light (or near infrared) spectroscopy identifies the electronic transitions. The employed technique is so-called action spectroscopy where absorption of laser light results in dissociation, fragmentation of ionization. For this research we have several laser systems available providing nanosecond pulsed light with wavelengths tunable between 195 and 2000 nm. For the absorption of infrared light, through the vibrational degrees of freedom in a frequency range from 100 cm-1 up to 500 cm-1, we move to the free electron laser FELIX (Free Electron Laser for Infrared eXperiments) of the FOM Institute for Plasma Physics Rijnhuizen (Nieuwegein, Nederland).



Promotor : Peter Lievens
Faculty/research group : Faculty of Science/Department of Physics and Astronomy
Daily supervision : Jorg De Haeck, Pieterjan Claes
Graduating option : Science/Nanoscience or Engineering/Nanotechnology
Type of work : experimental
Number of students : 2

Fabrication and characterization of carbon nanotube networks for strain-sensor applications
Carbon nanotubes (CNT) is an attractive material for MEMS applications because of its small size, high aspect ratio, low density, structural perfection as well as its excellent electronic and mechanical properties. Generally, applications that use CNTs as macroscopic assembly are promising, in
particular as a short-term solution, since they represent fast, uncomplicated and low-cost applications. However, CNTs strongly agglomerate and hardly disperse in a solution. Thus, their handling, positioning and alignment remain a constant struggle.

As CNTs are one-dimensional nanostructures, their macroscopic assembly exhibits a strong dependence of their physical properties on their alignment, in particular electric conductivity, mechanical as well as electromechanical properties. These characteristics also vary with the CNT diameter and defect density. Hence, two primary difficulties must be dealt with in constructing a successful CNT-based sensor: CNT structure characterization and CNT manipulation.

The aim of this master thesis is to fabricate CNT-based strain sensors and to gain fundamental understanding how the electromechanical response scales with the structural characteristics of CNTs, their density and alignment.

Objectives:
The objective of this master thesis is to grow CNTs and to fabricate macroscopic assembly of CNTs for the application of strain-sensors. This project covers the whole procedure starting from the growth, purification, characterization of CNTs as well as the fabrication and testing the strain sensor. Of great importance is the correlation between the electromechanical response and the CNT diameter distribution as well as the CNT alignment.

This master thesis involves the following experimental works:
- growth of multi-wall CNTs by catalytic chemical vapour deposition
- purification and functionalization of CNTs
- microstructural characterization of CNTs by means of electron microscopy techniques (SEM and TEM)
- alignment of CNTs by means of electrophoresis, fluidic manipulation or other techniques
- fabrication of CNT-based strain sensor on a polymer substrate
- measurement of the electromechanical response of the CNT assembly for various degree of alignment and for CNTs with different characteristics

Frame of the project:
This thesis work is strongly interdisciplinary and will be carried out in three different departments. The growth and chemical treatment of CNTs will be performed at VSM whereas characterization will be done at MTM. The sensor fabrication and testing will be done at MICAS.



Promotor : Jin Won Seo
Faculty/research group : ESAT-MICAS, VSM, MTM
Daily supervision : Jin Won (Maria) Seo (A2P2), Edina Couteau (VSM), Frederik Ceyssens (MICAS)
Graduating option : Master Engineering/Nanotechnology or Science/Nanoscience
Type of work : Experimental
Number of students : 1

Nanoparticles for Electron Emission Tumor Treatment
Context: Many different chemical and physical routes are currently followed of the treatment of tumor cells. One such method is based on the natural emission of Auger electrons from radionuclides such as 123I, whereby one decay releases about 15 electrons with an average energy of 7.5 keV. Disadvantages of this method are that i) only a limited number of discrete electron energies are available through Auger emission; ii) a limited set of such radionuclides exist and iii) these materials are continuous emitters (half-life 123I = 13.2h) and cause damage over their whole trajectory and lifetime.

An alternative method is to use an external x-ray photon source to excite photoelectrons and Auger electrons from selected materials. In this case, the energy of the photo-emitted electrons can be chosen quasi-continuously by changing the photon energy and the materials while also the discrete Auger electron energies remain available. To translate this method into a clinical application requires first the development of nanoparticles from selected materials followed by their attachment to selective antibodies or DNA aptamers that will then selectively bind to the cancer cells. Next these bioconjugated systems must be brought in contact with cancerous tissue and exposed to a photon source. In this master project the focus in on the first step.

Objective: Develop nanoparticles of selected materials and determine their photoelectron and Auger electron emission yield upon exposure to Cu Kα radiation.

Work to be done: Choose a few materials. Synthesize the corresponding nanoparticles of different sizes. Measure the emitted photoelectrons and Auger electrons.

Expected results: Proof of principle whether this method could be successfully used.



Promotor : Jean-Pierre Locquet
Faculty/research group : Faculty of Science / Faculty of Biomedical Engineerging
Daily supervision : Edina Couteau, Mariela Menghini
Graduating option : Science/Nanoscience or Engineering/Nanotechnology or Bioengineering
Type of work : Experimental, Simulations
Number of students : 2

Oxides with a high dielectric constant
Context: Dielectric oxides are key elements in many electronic devices for logic applications such as metal-oxide-semiconductor field-effect-transistors (MOSFET) as well as in several memory devices (FLASH and DRAM). For instance, in the latest 45 nm high performance chips, the gate oxide dielectric consists of ~ 3nm HfO2 (with a dielectric constant k = 25) replace the previously used SiO2 (k = 3.9). For future generations, the goal is to find oxides with an even higher dielectric constant (k = 40-50) while maintain a large band-gap (>5.5 eV) as indicated in the adjacent Figure (Goal LD). This is significant challenge that goes against the trend indicated in the Figure, namely that the band-gap decreases as the dielectric constant increases. Also k is very sensitive to structural details and for ZrO2 for instance, k in thin films can vary by a factor of 3.

In this project, the goal is to tune the structure and the space-group of selected oxide dielectric compounds and to determine how the dielectric properties change. This can be achieved for instance by growing oxide thin films on non-centrosymmetric substrates or by changing the structure through doping.

Objective: Determine the dielectric properties of selected oxide compounds with modified structural properties.

Work to be done: Select the appropriate dielectric compound. Grow thin films of the dielectric on substrates with different structure and space-group. Measure the structural and dielectric properties.

Expected results: Demonstrate how far the dielectric properties can be tuned for a selected material.



Promotor : Jean-Pierre Locquet
Faculty/research group : Faculty of Science and Faculty of Engineering
Daily supervision : Kabir Bhuyian, Mariela Menghini
Graduating option : Science/Nanoscience or Engineering/Nanotechnology
Type of work : Experimental
Number of students : 2

Piezoelectric properties of electro-optical materials
Context: In recent years there has been spectacular progress in the development of novel organic materials for electro-optical applications. These materials have a specific structural construction that induces a permanent charge distribution (a dipole) across the molecule. This non-centrosymmetric construction is illustrated in the adjacent Figure for a porphyrine derivate whereby both the charge difference and the distance between the positive and negative charge centers determine the magnitude of the electric dipole moment. The electric field that appears in the molecule can couple easily with external electromagnetic waves (electro-optical EO effect) or mechanical forces (piezo-electric PE effect).

Recently large EO coefficients have been measured in these new organic materials. Since the EO and the PE coefficient are in principle related to each other via the same dipole moment it is expected that these materials should have a large PE coefficient. If a significant PE coefficient is found then this opens the door to many potential applications in sensors and actuators.

Objective: Determine the PE coefficient of organic materials with a large EO coefficient.

Work to be done: Choose a few interesting organic compounds. Make thin films of these compounds. Determine the electrical properties and the PE coefficient.

Expected results: Proof of principle experiment to determine whether indeed a large PE coefficient is found.



Promotor : Jean-Pierre Locquet
Faculty/research group : Faculty of Science
Daily supervision : Edina Couteau, Mariela Menghini
Graduating option : Science/Nanoscience or Engineering/Nanotechnology
Type of work : Experimental
Number of students : 2

Oxide semiconductors with high mobility and low band-gap
Context:
Currently, semiconductor technology combines two very different and often incompatible materials, namely simple semiconductors and oxides. The former (Si, Ge) are essential for efficient carrier transport while the latter enable various functionalities (dielectrics, ferroelectrics, piezoelectrics, etc.). However these material incompatibilities often lead to sub-optimal properties and devices.

To propose a remedy for this challenge, the goal in this project is to develop oxide semiconductors with properties comparable to those of the simple semiconductors. This goal is schematically illustrated in the adjacent Figure where the band-gap and the mobility of many oxide semi-conductors are plotted together. It must however be noted that many reported oxides have never been made with the best possible deposition techniques. In addition, the properties of many oxides have never been explored for this purpose.

Objective: Find oxide semiconductors with high mobility (electrons and/or holes) in excess of 1000 cm2/Vs and small band-gap (0.6 - 2 eV).

Work to be done: Choose a few interesting oxide semiconductors systems. Grow single crystal epitaxial thin films of these oxide semiconductors. Measure the structural quality of these films. Determine the carrier type, the mobility and the band-gap.

Expected results: Knowledge of the electrical properties of single crystal films of several oxide semiconductors.



Promotor : Jean-Pierre Locquet
Faculty/research group : Faculty of Science
Daily supervision : Mariela Menghini, Kabir Bhuyian
Graduating option : Science/Nanoscience or Engineering/Nanotechnology
Type of work : experimental
Number of students : 2

Electric field induced metal - insulator - transition (MIT)
Context: For non-volatile memory (NVM) applications, the goal is to change from flash technology towards more compact and scalable designs using alternative mechanisms. Phase change (PCM) and resistive switching memories (RRAM) are two popular approaches, but in this project we excludes mechanisms relying on transport and rearrangement of atoms and concentrate on purely electronic phase transition between an insulating and a metallic state.

There are many materials that show a MIT for instance as a function of doping. The adjacent Figure shows the resistivity changes versus temperature for the Pr(Ca,Sr)MnO3 compound. In this project, the goal is to find systems that display an MIT at high temperatures (>400K). In addition the MIT must be switchable by an electric field. The resistance ratio between the metallic and the insulating state should exceed 10^5.

Objective: Develop an electric field induced MIT at high temperatures (>400K) with a resistance ratio in excess of 10^5.

Work to be done: Choose a few interesting MIT candidate materials. Grow single crystal epitaxial thin films of these oxides. Measure the structural quality of these films. Deposit a dielectric and a metal contact on top of the MIT oxide. Measure the electric field dependence of the resistance as well as the temperature dependence .

Expected results: Demonstration of electric field induced changes in the resistivity.



Promotor : Jean-Pierre Locquet
Faculty/research group : Faculty of Science
Daily supervision : Kabir Bhuyian, Mariella Menghini
Graduating option : Science/Nanoscience or Engineering/Nanotechnology
Type of work : Experimental
Number of students : 2

Synthesis of Transition Metal Oxide Nanotubes and their Application in Environmentally Friendly Catalysis
In the course of the Master thesis, the student will learn how to synthesize and characterize transition metal oxide nanotubes. Due to the tunability of their surface composition and pore diametres, their thermal stability and the presence of transition metals in various oxidation states, one can expect superior catalytic properties of these materials. Hence, the research interest not only focuses on the synthesis but especially on the application in oxidation catalysis.
The synthesis techniques that will be applied includes the use of Atomic Layer Deposition (ALD). This technique allows for the uniform coating of templates (e. g. mesoporous silica templates) on the basis of group V transition metal oxides (V2O5, Nb2O5, Ta2O5) to synthesize novel heterogeneous catalysts. Besides, the classical sol-gel synthesis followed by a hydrothermal treatment of the reaction mixtures will be used and explored to obtain these mesoporous transition metal oxides. ALD will be performed at U. Gent, in the laboratory of Prof. Ch. Detavernier.
The structure of the materials will be routinely characterized using Fourier-Transform Infrared Spectroscopy (FT-IR) and X-ray powder Diffraction (XRD). Concerning the thermal stability that is of major importance in heterogeneous catalysis, Thermogravimetric Analysis (TGA) will be conducted. More sophisticated analytical techniques like Transmission/Scanning Electron Microscopy (TEM/SEM) and Energy-Dispersive X-ray Mapping (EDX) will be applied to clarify the causes of outstanding catalytic performances. Some of these measurements will be done at TU Darmstadt (Germany). A stay in Darmstadt is an option.

Promotor : Johan Martens
Faculty/research group : FBIW, Centre for Surfacechemistry and Catalysis
Daily supervision : J. Emmerich
Graduating option : Bioengineering or Engineering/Nanotechnology or Science/Nanoscience
Type of work : experimental
Number of students : 1

Templates!
Porous materials like the zeolites are important as catalysts or adsorbents in industry. Even though there are infinite possibilities to connect the Silica units into crystalline pore structures only a limited number is known by now. But any catalytic process can only be as efficient as the catalyst. That means we need to understand the formation of zeolites to design the optimum material for a reaction.
During Zeolite synthesis organic template molecules are responsible for the formation of the open, porous structure. Templates can have several roles: They can act simply as a void filler around which the silica is shaped, they can create the right colloidal conditions for a specific nanoparticle to be formed, or they can directly shape the framework source into building nanounits which then assemble into the final lattice. But during zeolite synthesis not only the framework source is changed by the template. The interaction goes both ways and also the template molecules are affected. This causes sometimes the development of frameworks which at first sight should never have formed.
Only through detailed understanding of template framework interaction we will be able to direct zeolite synthesis towards a desired structure. This thesis will focus on systems where very different template molecules result in the same zeolite structure. A systematic study of the state of the template and the state of the frameworks will reveal molecular level information on how organic molecules shape porous materials and vice versa. For this systematic NMR studies (together with the University in Versailles) and Raman/Diffraction studies with localisation of the template molecules are foreseen. Complementary molecular and force field modelling (together with the Center for Molecular Modelling in Gent) will allow a detailed interpretation of the experimental results.

Promotor : Johan Martens
Faculty/research group : FBIW, Centre for Surfacechemistry and Catalysis
Daily supervision : C. Kirschhock
Graduating option : Bioengineering or Engineering/Nanotechnology or Science/Nanoscience
Type of work : experimental, theoretical
Number of students : 1

Fundamental aspects of metal organic framework formation
Metal organic frameworks (MOFs) belong to a new class of crystalline, porous materials where precisely defined subunits form complex structures by self-assembly on nanoscale. These superstructures exhibit completely different functionalities compared to those of the individual building blocks. The formation process involves coupling of covalently bonded subunits by noncovalent interactions. Not much is yet known about the detailed pathway of this self-organisation. Though metal organic frameworks show high promise for gas storage, separations, or catalysis, the formation process of MOFs still remains largely unexplained and new MOF structures are often only generated by trial and error approach. During this master project you will gain fundamental insight into the formation process of MOFs using various sophisticated diagnostic techniques like X-ray diffraction, dynamic light scattering (DLS) and synchrotron small angle X-ray scattering (SAXS). On selected systems NMR spectroscopy will be used to follow the state of coordination of the framework nodes consisting of transition metals. Your study will be a remarkable contribution towards understanding of self-organisation leading to supramolecular assemblies and will lead directly to the directed synthesis of novel materials which could open up a wide range of potential applications.

Promotor : Johan Martens
Faculty/research group : FBIW, Centre for Surfacechemistry and Catalysis
Daily supervision : S. Bajpe
Graduating option : Bioengineering or Engineering/Nanotechnology or Science/Nanoscience
Type of work : experimental
Number of students : 1

Lego Chemistry
Functional porous materials not only depend on the efficiency of their active sites but also on the transport of molecules to and from these sites. While only the right molecules should be able to reach the active sites the flow through a porous material should not be hindered too much. This calls for a hierarchical structure where large pores in the material act like the highways bringing the feed close to the active sites and smaller pores which only the right molecules can enter to reach the active site.
We have developed a way to use nanoscale zeolite precursors to create such hierarchical structures. First the zeolite precursors are formed, then they are packed into nanoslabs, and finally the slabs are stacked in an open but well ordered arrangement (https://perswww.kuleuven.be/~u0016996/CEAKs%20space%20lego.html) .
Even though we were able to create this new class of materials we still need to learn more about the rules which cause the formation of the slabs and then their organisation into a lattice to give us more controle on the properties of the zeotiles. Detailed in situ studies are planned using DLS (together with the Deparment of Chemical Engineering) and with Small Angle Xray scattering (at the European Synchrotron ESRF http://www.esrf.eu/ ). NMR studies will reveal the changes of silica connectivity (together with the Department of Chemistry and the University in Versailles) and Transmission Electron Diffraction will reveal the detailed stacking of the slabs (together with EMAT in Antwerp http://www.emat.ua.ac.be/ ) You will be part of an international team busy playing Lego!

Promotor : Johan Martens
Faculty/research group : FBIW, Centre for Surfacechemistry and Catalysis
Daily supervision : Sreeprasanth Pulinthanathu
Graduating option : Bioengineering or Engineering/Nanotechnology or Science/Nanoscience
Type of work : experimental
Number of students : 1

Heteroatoms in Zeolites - probing nanoscale self-organisation into 3D structures
Porous materials like the zeolites are important as catalysts or adsorbents in industry. Even though there are infinite possibilities to connect the Silica units into crystalline pore structures only a limited number is known by now. But any catalytic process can only be as efficient as the catalyst. That means we need to understand the formation of zeolites on atomic and nanoscale to design the optimum material for a given application.
By now we have a rough idea how zeolite frameworks are actually formed but these results were obtained only for a purely siliceous zeolite. However – zeolites often contain heteroatoms in their framework which define their functional activity. The presence of these heteroatoms like aluminum or germanium affects the whole lattice formation and our task is to understand how these atoms are integrated into the crystal.
As study object will serve the industrially important frameworks of zeolite LTA and MFI formed in the presence of Ge and Al. Detailed in situ studies are planned using DLS (together with the Deparment of Chemical Engineering) , Small Angle Xray Scattering and Xray Absorption (at the European Synchrotron ESRF http://www.esrf.eu/ ). NMR studies will reveal the changes of silica connectivity (together with the Department of Chemistry). Studies under elevated gravity in the Large Diameter Centrifuge (LDC) of ESA (http://www.esa.int/esaTQM/1202207743187_mechanical_0.html) are also planned to support the preparation of an experiment of zeolite formation on the International Space Station.
This Master project will give important insights how the heteroatom distribution in a zeolite can be directed on nano- and atomic scale.


Promotor : Johan Martens
Faculty/research group : FBIW, Centre for Surfacechemistry and Catalysis
Daily supervision : N. Kasian
Graduating option : Bioengineering or Engineering/Nanotechnology or Science/Nanoscience
Type of work : experimental
Number of students : 1

Nanoscale structured biomolecule-silica composites
Silica (SiO2) often is called the inorganic carbon as is is structurally extremely variable. The SiO4 tetrahedra can link in infinite ways, either forming dense phases with interesting electrical and optical properties or in open crystalline or amorphous structures. The pore size of the latter can be adjusted by synthesis conditions and additives which form composites with the silica during formation. For industrial applications mostly micro- and mesoporous silica is for example as catalyst or sorbent. Recently silica gains more and more importance for controlled drug release for therapeutic use for example as nanocapsules. The rapidly increasing use of bio-macromolecules, like proteins or enzymes, for medical purposes calls for specifically gentle conditions for encapsulation in a carrier. Up to now silica was used only rarely as the condensation reaction of the silicon source either occurs at acidic or basic conditions and often at elevated temperatures, where the active organic compound is destroyed.
At the COK a new way to assemble silica into either 3D networks or nanosized particles at neutral pH and room temperature was developped. Under these conditions biomolecules are stable and can be used to structure the inorganic material. This important discovery now opens a way for design of a whole new class of synthetic silica-biomolecule composites. In these composites enzymes or specifically marked fluorescent molecules can be immobilised and not only applications in the medical sector but also applications as catalyst or optical materials come into reach.
In this project you will be one of the first who will explore the synthesis and application of these exciting new materials.
The parameters influencing the formation of the bio-inorganic composites will be thoroughly screened and the obtained materials characterised using a wide range of diagnostics (NMR, Dynamic Light Scattering, Small Angle X-ray Scattering, TG, porometry, flurescence spectroscopy and other spectroscopic means). This way optimised conditions for gentle biomolecule encapsulation will be formulated.

Promotor : Johan Martens
Faculty/research group : FBIW, Centre for Surfacechemistry and Catalysis
Daily supervision : A. Aerts, C. Kirschhock
Graduating option : Bioengineering or Engineering/Nanotechnology or Science/Nanoscience
Type of work : experimental
Number of students : 1

Assembly of functional materials from 2D and 3D nanoscale building blocks
Bifunctional catalysis especially acid catalysis coupled with hydrogenation and dehydrogenation steps occurring on Pd or Pt centers are invaluable in view of the threatening depletion of crude oil. With this catalytic strategy small molecules like methanol can be directly converted to longer molecules especially the much craved C4 and C6 fractions. However, today many of these processes still run in homogeneous systems involving for example a Pd-complex in sulfuric acid, which leads to costly and environmentally dubious posttreatment and purification steps. A further important class of catalysts are the photoactive materials allowing the direct conversion of light energy into compounds with added value.
In this master thesis an entirely new material will be studied for its potential as bifunctional and photoactive catalyst. Uehara et al in 2007, reported the synthesis of twodimensional Pd-based metaloganic frameworks (MOFs). These supramolecules are triangular or square compounds having large pores, leaving the metalcenters accessible. The catalytic properties of these 2D MOFs could be enhanced by introducing acidic oxide clusters like polyoxometalates (POMs) into the large pores and between the MOF sheets. Your project will explore how the nanoscale building units like the 2D Pd complexes and the 3D POMs can be assembled into 3D materials. Photoactivity can be achieved by using POMS with substituted luminiscent metal centres. The synthesis of the POMS will occur in collaboration with T. Vogt in the chemistry faculty.
You will test stability of the obtained composite materials at different temperatures, and study their catalytic properties. For characterisation you will be using various techniques like the X-ray diffraction, dynamic light scattering (DLS), synchrotron small angle X-ray scattering (SAXS), thermogravimetric analysis (TGA), and nitrogen sorption. The most promising materials will be used in test reactions probing their potential for bifunctional and photocatalysis. During this master project you will learn to assemble nanoscaled 2D structures into 3D composite materials, and test and optimise them for catalytic applications.

Promotor : Johan Martens
Faculty/research group : FBIW, Centre for Surface chemistry and Catalysis
Daily supervision : S. Bajpe
Graduating option : Bioengineering or Engineering/Nanotechnology or Science/Nanoscience
Type of work : experimental
Number of students : 1

Biologically Inspired Hydraulic Microactuators
The objective of this master thesis is the development of microactuators driven by pressurized liquids. Prior research on classic (piston-cylinder) hydraulic actuators at the KULeuven has shown that these systems achieve extremely high force and power densities at microscale. A disadvantage of this technology is that hydraulic microactuators are difficult to seal. In this project, a new generation of hydraulic actuators will be developed by mimicking biological hydraulic systems such as found for instance in the legs of spiders.

Because of the intrinsic elastic and three-dimentional geometries of biological systems, we envisage combining soft lithographic processes such as PDMS moulding with 3D fabrication processes such as micromilling and multi-step SU8 lithography. A lot of expertise in these production techniques is present at the KULeuven, which will ensure a fast start of the project.

Biomimetic hydraulic actuators are important for the microsystems community because they will achieve high forces and large strokes at microscale without any leakage of driving fluids. In addition, biomimetic actuators are typically compliant and are therefore interesting for several microrobotic applications. It is for instance a goal of this research to push these actuators towards integration in a gripper for minimally invasive surgery. Depending on the progress of the research, the integration of position or force sensors in the actuator will also be investigated in order to enhance the dexterity of the microrobots.

It is important to note that this thesis will not be limited to theoretical analysis and simulations. A major aspect of the research will be the development of the components using micromachining technologies and testing.



Promotor : Dominiek Reynaerts
Faculty/research group : Engineering/ESAT-MICAS
Daily supervision : Frederik Ceyssens, Michael De Volder
Graduating option : Engineering/Nanotechnology or Bioengineering
Type of work : experimental, theoretical, simulations
Number of students : 2

CMOS Compatible Poly-Mems 2-D Tilt Sensor Design
Tilt Sensor has been widely used nowadays in many astonishing applications. In game industry, Netendo used Tilt Sensor technology for its Game Boy series of hand-held game systems. For the Wii Remote, along with accelerometers, the tilt sensors are a primary method of control in most Wii games. Except for the game industry, tilt sensors find their way also in Segway vehicle, which can maintain balance on two parallel wheels while traveling.

In personal digital products, 2-D tilt sensor has been used in iPhone and some high-end digital cameras to offer a smart human-machine interface, helping to decide the upward direction of the device and adjust the display accordingly.

The major objective of this thesis proposal is to design a 2-D Tilt Sensor based on the POLY-MEMS technology of MICAS. Since POLY-MEMS features low heat budget, flexible, and good mechanical properties, it will be promising to achieve the proposed device to detect any 90 degree shift of the device relative to the gravity.

Work to be done:
10% theory studying and digesting;
35% sensor layout CAD design and optimization;
40% sensor manufacturing with MICAS cleanroom
facility;
15% Sensor characterization and result analysis.

Expected result:

1. Novel 2-D Tilt Sensor design;
2. To be familiar with MEMS technology and achieve proposed device;
3. Reasonable result analysis.



Promotor : Robert Puers
Faculty/research group : ESAT/MICAS/SENSOR GROUP
Daily supervision : Lianggong Wen
Graduating option : Engineering/Nanotechnology
Type of work : experimental
Number of students : 2

Polymer based Optical Micro-Grippers
Micro-tweezers have been developed by many researchers for manipulate bio-cells. They have the ability to manipulate single cell. Meanwhile, optical fiber biosensors have been touted as the means to revolutionize medical technology, dramatically improving patient care and cutting overall operating costs. They are immune to electromagnetic signals and are currently used in a variety of medical applications.

The major objective of this thesis is to design and fabricate a polymer based micro-tweezers. An optical wave path will be integrated into the tweezers. This combination will realize the attractive idea to visualize the micro-tweezers with optical bio-detection ability.

Work to be done:
10% theory studying and digesting;
35% sensor layout CAD design and optimization;
40% sensor manufacturing with MICAS cleanroom
facility;
15% Sensor characterization and result analysis.

Expected result:

1. Polymer based optical micro-tweezers design;
2. To be familiar with MEMS technology and achieve proposed device;
3. Sound result analysis.

Reference:
Figure used is partly from the work of Monolithically Fabricated Microgripper With Integrated Force Sensor for Manipulating Microobjects and Biological Cells Aligned in an Ultrasonic Field¯, JOURNAL OF MICROELECTROMECHANICAL SYSTEMS, VOL. 16, NO. 1, FEBRUARY 2007.



Promotor : Robert Puers
Faculty/research group : FW/ESAT/MICAS/SENSOR GROUP
Daily supervision : Lianggong Wen
Graduating option : Engineering/Nanotechnology
Type of work : experimental
Number of students : 2

Development of novel electrode arrays for Cochlear Implants
The Cochlear Technology Centre in Mechelen, Belgium investigates electrode
technologies with potential to manufacture less invasive arrays with improved electrode
neural interfaces. Both aspects are crucial to bring a better sound quality to the recipients
under all daily-life conditions. In our present projects we explore the capabilities of
existing technologies, such as MicroSystems and nano technologies or laser processing,
to build new electrode types. These electrodes are designed to gain more knowledge
about some of the fundamental questions related to Cochlear Implants.

How can we improve the implant performances by increasing the number of electrode
contacts from 22 (at present) to 100? What is the ideal electrode morphology to
accomplish a better coupling between the electrodes and nerve fibres? … In this thesis
project, we will introduce the student to the different electrode projects in Cochlear. We
will explain different types of commercial and research electrode arrays to demonstrate
the student the present challenges in design and development of active implantable
medical systems. After a few weeks, the student will select one specific project to
elaborate during the rest of the thesis period. The student will follow the whole process
chain from electrode design, prototyping and testing including, for some projects, animal
experiments.



Promotor : Robert Puers
Faculty/research group : Engineering/ESAT-MICAS
Daily supervision : Bart Volckaerts, Frederik Ceyssens
Graduating option : Engineering/Nanotechnology
Type of work : experimental
Number of students : 2

Nanoscale chirality
Context: Chiral chemical systems with nanometer scale features - the effects of chirality on structuring at the nanoscale, how chirality is recognized and transferred at the molecular and supramolecular levels, how chirality is expressed in terms of chemical interactions and physical properties - are of vital significance to society as a whole because of the socio-economic areas where chiral products are the merchandise. Pharmaceutical science depends largely on chiral recognition, it is important for catalysis for the fine chemicals industry, and in liquid crystal displays. A major concern is the separation of enantiomers in a mixture. How to separate molecules which are identical, except for the fact that they are mirror images?

Objective: The objective is to probe how chiral molecules self-assemble on surfaces (the enantiomers and racemic mixtures) and how the separation of enantiomers on a surface can be promoted and controlled. A further objective is the use of chiral monolayers to direct the enantiospecific crystallization of other molecules in solution.

Work to be done: First, you will investigate the self-assembly of chiral molecules using scanning probe microscopy tools, the pure components, as well as their mixtures. In addition, you will probe the interaction of these template layers with other molecules, in order to find out if separation is possible. Finally (if time allows), you will use these molecular layers as templates for the directed crystallization of molecules in solution.

Expected results: New method for chiral separation on surfaces.




Promotor : Steven De Feyter
Faculty/research group : Science / Division of Molecular and Nano Materials
Daily supervision : Inge De Cat
Graduating option : Science/Nanoscience or Engineering/Nanotechnology
Type of work : Experimental + modelling
Number of students : 1

Nanopatterning using the bottom-up approach: addressing the 5 nm to 15 nm regime
Context: Patterning surfaces with a periodicity between 5 and 15 nm is not obvious. On the one hand, state-of-the-art lithography techniques could be used via a top-down approach. On the other hand, self-assembly methods are promising to achieve such patterns with a high fidelity via a bottom-up approach. Self-assembled monolayers of alkylthiols on gold are a textbook example of chemisorbed systems. Typically, they are spontaneously formed by exposing a gold surface to a solution containing the alkylthiols As a result, they form a homogeneous monolayer on gold. How to pattern them? Using soft-lithography, it is possible to pattern 'patches' of these self-assembled monolayers. The spatial resolution is limited to about 50 nm though. Can one do better?

Objective: The objective is to pattern patches of self-assembled monolayers with a periodicity between 5 and 15 nm on gold. The approach you will follow is the use of nanoporous physisorbed monolayers as templates for the self-assembly of the chemisorbed systems. Basically, the alkylthiols should 'fill' the nanopores.

Work to be done: First, you will investigate the self-assembly properties of the molecular templates on gold. Among different techniques, you'll use atomic force and scanning tunneling microscopy. Subsequently, you will target the self-assembly of the alkyl thiols in the nanopores. You will investigate the stability of these patches after removal of the template layer and their functionality.

Expected results: Superior patterning method for alkyl thiols on gold.



Promotor : Steven De Feyter
Faculty/research group : Science / Division of Molecular and Nano Materials
Daily supervision : Jinne Adisoejoso
Graduating option : Science/Nanoscience or Engineering/Nanotechnology
Type of work : Experimental
Number of students : 1

Raman spectroscopy with nanometer resolution: beating the diffraction limit
Context: A relatively new but very exciting development in self-assembly is the formation of molecular nanopatterns on surface with a spatial periodicity between 1 and 10 nm. Especially, the formation of 2D nanoporous patterns is 'hot'. Scanning tunneling microscopy is an ideal tool to probe their self-assembly. Unfortunately, this technique barely provides information on the chemical nature of the species adsorbed.

Objective: The objective is the development and implementation of a new technique, called Tip Enhanced Raman Scattering (TERS) to probe the composition of thin films (monolayers) with nanometer-scale resolution on surfaces. This is basically the only approach to spectrally characterize monolayer composition at the nanoscale. In TERS a STM or AFM is coupled with Raman spectroscopy. The electromagnetic field confined at the very end of the tip (in few nm region) induces Raman scattering. The principle is based on surface-enhanced Raman scattering (SERS) which is known to enhance the Raman scattering cross section by a factor of 1015 to 1016, resulting in a similar sensitivity as fluorescence. Therefore, a single-molecule sensitivity can be reached with this technique

Work to be done: First, you will set-up Tip Enhanced Raman Scattering. In a second stage, you'll investigate its sensitivity and spatial resolution, by using "standard" samples and self-assembled monolayers.

Expected results: Accomplishing the setup of Tip Enhanced Raman Scattering. First results on sensitivity and spatial resolution on functional molecular nanopatterns physisorbed on atomically flat gold.



Promotor : Steven De Feyter
Faculty/research group : Science / Division of Molecular and Nano Materials
Daily supervision : Hiroshi Uji-i
Graduating option : Science/Nanoscience or Engineering/Nanotechnology
Type of work : Experimental + simulation
Number of students : 1

Molecular Nanovalves
Context: A relatively new but very exciting development in self-assembly is the formation of molecular nanopatterns on surface with a spatial periodicity between 1 and 10 nm. Especially, the formation of 2D nanoporous patterns is 'hot'. There are compounds which intrinsically contain a cavity such as macrocycles. However, nanoporous structures can also be formed by intrinsically non-porous molecules. These nanopores can host guest species. However, so far it is not possible to fill or empty the pores on demand. Recently, we have designed in collaboration with a Japanese group a system which in principle should allow us to do so.

Objective: The objective is to self-assemble on a surface a 2D array of molecular valves which can be addressed by light.

Work to be done: By means of high-resolution scanning tunneling microscopy techniques, you will investigate the self-assembly of the functional nanoporous matrix and its ability to trap guest molecules. Subsequently, you will probe the response of the system to light and evaluate the efficiency of these molecular nanovalves, which have a diameter of less than 10 nm.

Expected results:

First demonstration of molecular nanovalves on a surface



Promotor : Steven De Feyter
Faculty/research group : Science / Division of Molecular and Nano Materials
Daily supervision : Shengbin Lei
Graduating option : /Nanoscience or Engineering/Nanotechnology
Type of work : Experimental
Number of students : 1

Two-dimensional nanoporous materials: reactivity in confined space
Context: A relatively new but very exciting development in self-assembly is the formation of molecular nanopatterns on surface with a spatial periodicity between 1 and 10 nm. Especially, the formation of 2D nanoporous patterns is 'hot'. There are compounds which intrinsically contain a cavity such as macrocycles. Upon twodimensional (2D) self-assembly, a regular lattice of these macrocycles (and therefore also the cavities) can be formed, which subsequently can be addressed by guest particles. However, such porous structures can also be formed by intrinsically non-porous molecules. These porous networks are typically sustained via hydrogen bonds, metal-ligand coordination or even van der Waals interactions. Recently, our group has developed, in collaboration with a research team in Japan (Osaka University), a molecular system which forms 2D porous matrices which are in many aspects superior to those described in literature.

Objective: These two-dimensional nanoporous materials are ideal to host (reactive) molecular species. It is the objective to capture guest molecules in these nanoporous sites and to carry out chemical reactions in the nanovessels.

Work to be done: By means of high-resolution scanning tunneling microscopy techniques, the self-assembly of the nanoporous matrix and its ability to trap reactive species will be investigated. Then, the in-situ reactivity of the trapped species will be probed by scanning probe and other techniques.

Expected results:

First demonstration of reactivity in molecular nanoporous systems on a surface.




Promotor : Steven De Feyter
Faculty/research group : Science / Division of Molecular and Nano Materials
Daily supervision : Shengbin Lei
Graduating option : Science/Nanoscience or Engineering/Nanotechnology
Type of work : Experimental + simulation
Number of students : 1

Characterization and spectroscopy of organic quantum dots
It can be expected that block copolymers of conjugated polymers consisting of sections with hydrophobic and sections with hydrophylic side chains form in aqueous medium a micelle with a core of hydrophobic side chains and a shell of hydrophilic side chains. The prompts questions on possible aggregation of the chromophores, the occurrence of energy hopping and the possibility to form a single quantum dot. This means e.g. that independent of the exictiaton intensity a micelle can only emit a single photon at a time. It also means that we can expect blinking of the fluorescence of a single micelle. In this latter case a safe (no cadmium) and flexibly adaptable alternative for inorganic quantum dots would exist for in medic-diagnostic applications an as research tool in molecular biology.
The polymers we will receive from the division of "Molecular Design and Synthesis" of K.U.Leuven, through of UHasselt, or the "Max Planck Institut für Polymerforschung" in Mainz. In a first step we will in collaboration with the UCL (team of prof. A. Jonas) check if the polymers form micelles and try to find out the size of those micelles using e.g static and dynamic light scattering.
We will try to answer the questions mentioned above regarding the fate of the excitation using stationary and time-resolved fluorescence spectroscopy on bulk samples. As it is possible that the properties of single micelles will be subject to a broad distribution we will try to characterize the fluorescence properties of single micelles using a confocal microscope. Besides their fluorescence spectra and fluorescence decay we will also try to find out if fluctuations of those properties occur during the course of time. If necessary single micelles will be immobilized by trapping them in an infraredlaser beam of a CW Nd: Yag laser.

Promotor : Mark Van der Auweraer
Faculty/research group : FW/Chemie
Daily supervision :
Graduating option : Science/Nanoscience or Engineering/Nanotechnology
Type of work :
Number of students : 2

Study of colloidal phase transitions of nanoparticles by direct visualization with super resolution optical microscopy
One of the most promising developments in fluorescence microscopy is the invention of schemes that allow obtaining an improved, nanoscale, resolution in fluorescence microscopy. To date, two types of approaches have successfully established. The first one is based on zero-intensity-based read-out (STED), the second one on stochastic photoactivation and localization of single molecules (PALM/STORM). The PALM method is based on cycles of stochastic switching on, reading out and switching off of individual fluorophores. Within a cycle, the activated molecules should be well enough separated from each other (further apart than the distance resolved by the microscope). It is then possible to localize with high precision the centroid of the individual fluorescent signals for each cycle and construct a subdiffraction-limited image of the sample incorporating all the centroid positions of all the cycles. With these super resolution optical microscopy modes, objects as small as 30-50 nm can be imaged. The time scale of PALM/STORM and STED is sufficient to allow direct visualization of the dynamics of selected phase transitions of colloidal systems (30-50 nm fluorescent NPs).
Objectives: The goal of this project is to use PALM microscopy and or STED microscopy for the real time, in situ study of phase transitions in colloidal systems.
Work to be done: Until now mainly colloidal systems based on micrometer sized particles have been imaged by confocal fluorescence microscopy. We propose to expand colloidal science in the realm of nano by using superresolution microscopy. For this research task we will start with the investigation of the simplest possible experimental system of interacting particles: hard colloidal spheres (dye labeled nano-particles (NPs) that will be obtained via several collaborations). These NPs can then be modified by grafting them with polymer patches, which leads to directional and anisotropic interactions between the particles. The explicit goal of the project is to link the microstructure and dynamics of sub-micron particles with macroscopic properties, which also includes their investigation by established rheological methods (expertise of Prof Vermant)
Expected results: One expected result is the first direct observation of phase transitions of nanometer sized colloidal particles. We also expect to establish the influence of different types of interactions (between the NPs) on colloidal dynamics.

Promotor : Jan Vermant
Faculty/research group : Faculty of Science, Division of Molecular and Nanomaterials, Laboratory for Photochemistry and Spectroscopy
Daily supervision : Hiroshi Uji-i
Graduating option : Science/Nanoscience or Engineering/Nanotechnology
Type of work : experimental
Number of students : 2

Multi-bead assays for protein or DNA detection
The introduction of biosensors into the market is partly hampered by their limited clinical sensitivity. The use of optical and magnetic labels can strongly enhance both specificity and sensitivity. In a recently developed multibead assay (called bio-barcode assay) the detection of nucleic acid and protein targets has been shown to be extraordinarily sensitive. In this assay, the analytes of interest are bound in a sandwich assay by both magnetic and gold beads. The magnetic beads are used to isolate the two-bead complexes, while the gold beads contain a high number of oligonucleotides (barcodes). These barcodes are released for detection. As such, the signal is largely increased over the detection of single analytes. In this thesis, the optimization and use of multi-bead assays will be further investigated. Development of a method to separate bead-analyte complexes will pave the path towards fully-integratable lab-on-a-chip platforms.

Main techniques (amongst others): 2D and 3D surface chemistry, DNA and protein assays, gold nanoparticle synthesis, magnetic nanoparticle characterizations, magnetic capturing, optical detection methods, fluorescent spectroscopy, etc.

Promotor : Jeroen Lammertyn
Faculty/research group : FBIW/FW/IMEC/Functional nanosystems
Daily supervision : Tim Stakenborg
Graduating option : Bioengineering or Science/Nanoscience or Engineering/Nanotechnology
Type of work : experimental
Number of students : 1

PDMS chip prototyping for individual droplet manipulations
Microfluidic systems are getting increasingly more important for biosensing and catalysis applications. These lab-on-a-chips integrate all necessary chemical reactions and biological interactions in a miniaturized and automated system. This miniaturization improves mixing and reaction rates at the nanoliter scale. Transport of liquids through the microchannels can be either continuous or as small droplets. This last approach resembles the real laboratory situation most and allows manipulation of small sample volumes without contamination.
The goal of this thesis is to design and develop a digital microfluidic platform, which is able to perform all basic droplet manipulations in microchannels. The negative pattern of the channels will be made in spin-coated SU-8 using soft-lithography. These features are typically in the range of 50 to 200 µm. Pouring liquid polydimethylsiloxane (PDMS) on this mould, followed by curing in an oven, results in a PDMS slab bearing all the channels and reservoirs. To close the channels a second slab of PDMS or a glass plate is used as cover. This can be sealed irreversibly with oxygen plasma, corona discharge or piranha solution. Finally tubes are used to connect the chip to extremely precise syringe pumps. This whole setup needs further improvement and it will be the student’s task to make and optimize the protocols. On the chip, discrete droplets are created with water and perfluor oil - two immiscible phases. One syringe pump pumps the oil trough the channels, while other pumps inject small droplets of watery samples. These droplets can be split, merged and mixed. Exploring the possibilities of this system will be a major task in this project.

For more information also see www.biosensors.be

Promotor : Jeroen Lammertyn
Faculty/research group : Division MeBioS, Department of Biosystems
Daily supervision : Bert Verbruggen
Graduating option : : Bioengineering or Engineering/Nanotechnology
Type of work : experimental
Number of students : 1

Fiber optic SPR biosensor for protein and nucleic acid detection
In the search for more convenient SPR biosensors, the MeBioS Biosensor group recently designed a fiber optic SPR platform, by integrating surface plasmon resonance technology with optical fibers. In the setup, replaceable and interchangeable sensing probes are affixed onto the end of a bifurcated optical fiber. This innovative, cheap and sensitive detection system needs further improvement with respect to fiber fabrication and biosensor development.
The objective of this thesis is to further develop this SPR optical biosensor to detect food allergen proteins (e.g., peanut allergens). The project consists of two parts.
The first part involves the optimization of the sensor platform with respect to sensor stability, sensitivity, fiber tip production and improvement of the biorecognition layer. The results of the fiber SPR system will be validated with the commercial BIACORE (GE Healthcare, Sweden) system. In the second part the student will search for suitable DNA (aptamers) and protein (antibody) bioreceptor molecules. A new aptamer will be designed using capillary electrophoresis. Aptamers are artificially developed DNA molecules, which just like antibodies can be used to capture target molecules, like for example food allergens. These receptor molecules will be immobilized on the optical fiber to study its potential and validate the biosensor in a real food application.

For more information see also www.biosensors.be

Promotor : Jeroen Lammertyn
Faculty/research group : Bioscience engineering/MeBioS
Daily supervision : Jeroen Pollet
Graduating option : Bioengineering or Engineering/Nanotechnology
Type of work : simulations, experiments
Number of students : 1

Digital microfluidics as a new emerging platform for bio-analytical assays
Microfluidics have become more and more present in the field of (bio)analytical chemistry. Everything started with the introduction of the micro-total analysis (µTAS) concept in 1990 by Andreas Mainz where microfluidics make up the main component. The aim of µTAS is to perform a complete and automated analysis on a small scale level. The benefits include short analysis time, high precision and repeatability and low reagent consumption. A recent trend in microfluidics is to manipulate the fluid in discrete droplets. Droplet manipulations like transport, merging, splitting and dispensing closely resembles the work done in a lab environment but with the advantage that manipulating droplets on a small scale can be carried out automatically and in high-throughput context without losing flexibility.
In this thesis we will study in more detail the potential of digital microfluidics. More precise, the objective of the thesis will be the investigation of digital microfluidics as a platform for performing bio-analytical assays. This work comprises of two major parts. Depending on the student's interest one topic or a combination of both might be chosen by the student. The first part involves the detailed investigation of droplet manipulations. Basic manipulations like droplet transport, splitting and dispensing need to be fully mastered and controlled in order to ensure a high precision and accuracy during the execution of bio-analytical assays. Special attention will be paid to the chip design, optimization and production in ESAT cleanroom facilities. The second part focuses on the implementation of a bio-analytical assay in the digital microfluidics platform. Antibody-antigen interactions in the framework of food allergen detection will be implemented. Signal amplification strategies based on fluorescent functionalized nanoparticles will be tested in this context.
Important here is to look at the consequences of the implementation on the performance of the assay. Strategies to overcome practical hurdles like bio-fouling and repeatability need to be developed.

For more information see www.biosensors.be

Promotor : Jeroen Lammertyn
Faculty/research group : Division MeBioS, Department of Biosystems
Daily supervision : Nicolas Vergauwe
Graduating option : Bioengineering or Engineering/Nanotechnology
Type of work : experimental
Number of students : 1

Single cell analysis on a digital lab-on-a-chip
Digital microfluidics refers to the transport of individual droplets on a chip, most commonly by the principle of 'electrowetting-on-dielectric' (EWOD). With this technology, droplets can be generated, transported, mixed and merged on a matrix of microelectrodes without the intervention of micropumps, microvalves, and microchannels as in the classical microelectromechanical systems (www.biosensors.be). The importance of this technology has increased during the last years with the development of new analytical methods and new fundamental insights in the area of e.g., enzyme kinetics, immunoassays and DNA-analysis. In this thesis this innovative technology will be used to execute cell-based assays. Such type of experiments are commonly executed in batch-scale, including large numbers of cells. However, due to improvements in detection and analysis techniques, single cell analysis (or analysis on a limited number of cells) has become possible recently. This type of analysis reveals fundamental physiological insights and knowledge with respect to the cellular heterogeneity as a result of the stochastic variability in the different molecular processes inside the cell ('biological noise'). This biological variability is crucial for the statistical interpretation of data, originating from proteomics or metabolomics. Recently the compatibility of cell based assays with digital microfluidics has been proven. However, the suitability of biophysical and biochemical analyses on the level of single cell with this technology has not been illustrated but the applied technology offers theoretically a lot of possibilities for measuring biophysical and biochemical properties of (individual) cells in microreactors: (i) cells are exposed relative easily to physical (e.g., temperature) and chemical stimuli (e.g., drugs, growth factors, toxic components, pH) by mixing individual droplets; (ii) the different assays can be executed simultaneously; (iii) the chip allows to monitor the different processes taking place inside the microreactor by coupling the chip to advanced visualization and analysis techniques; (iv) single cell analysis results in a more accurate measurement of biophysical and biochemical parameters of the cell, compared to analysis in batch experiments; (v) the technique allows to obtain unique information with respect to the biological variability on the level of the individual cell. This thesis serves as an exploratory study of the digital lab-on-a-chip technology with respect to (single) cell analysis. Depending on the background and/or interests of the student more concise research objectives will be defined.

Promotor : Jeroen Lammertyn
Faculty/research group : Faculty of Bioscience Engineering/MeBioS Biosensor group
Daily supervision : Steven Vermeir, Nicolas Vergauwe
Graduating option : Bioengineering or Engineering/Nanotechnology
Type of work : experimental
Number of students : 1

Nanoparticles as amplification tool in aptasensors
Biosensors are a subgroup of chemical sensors for which the detection of a target molecule is based on a specific interaction of this target molecule with a biorecognition element (e.g., enzyme, antibody, aptamer, micro-organism or cells). A wide range of transducers is available to detect the interaction between the target and the biorecognition molecule and convert it into an electronic signal. Biosensor technology has many applications in food quality and safety control, biomedical diagnostics and environmental monitoring.
In this project we will study the potential of aptamer bioconjugated nanoparticles as a signal amplification tool for biomolecule detection (DNA or proteins) in a lab-on-a-chip. The nanoparticles will be functionalized with aptamers, oligonucleotides which can be selected with high selectivity against almost any target molecule. The aptamer-target interaction will be visualized using the concept of nanoparticle aggregation through hybridization of the aptamer bioconjugated nanoparticles: aggregated nanoparticles display different optical fluorescent properties compared to the individual particles.

For more information see also www.biosensors.be

Promotor : Jeroen Lammertyn
Faculty/research group : Division MeBioS, Department of Biosystems
Daily supervision : Filip Delport
Graduating option : Bioengineering or Engineering/Nanotechnology
Type of work : experimental
Number of students : 1

Microfluidics modelling of biochips
Miniaturised analysis systems offer a cheap and easy-to-handle measurement platform for fast detection of biomolecules in small concentrations. Build into a microfluidic system, reagentia can be transported, mixed and separated accurately. The performance of the system depends to a large extent on the design of the microfluidic channels and components such as mixers and separators.

The objective of this thesis is to develop and assess the performance of fluid dynamics models for the description of the formation and handling of discrete fluid samples, such as droplet formation on digitial microfluidic platforms and capillary transport of fluids in microchannels.

The student will evaluate available CFD software packages for the modelling of capillary and surface tension problems in microchannels. A simplified channel geometry will be used as a benchmark system and validation of the different simulations will be performed by means of microscopy on available microfluidic chips. The student determines the accuracy and limitations of CFD siumations with the different software programs and determines guidelines for accurate use of simulation tools to describe discrete microfluidics. Finally, a complex biochip is modelled and the channel layout is assessed in terms of performance (avoiding air entrapment).

For more information see also www.biosensors.be

Promotor : Jeroen Lammertyn
Faculty/research group : Bioscience engineering/MeBioS
Daily supervision : Pieter Verboven
Graduating option : Bioengineering or Engineering/Nanotechnology
Type of work : simulations, experiments
Number of students : 1