Possible Master Thesis Topics

Where can you do research in a motivating environment? Implement your own ideas? In the field of Material Physics of course. Below are several current topic possibilities for your Master thesis:


 ______________ 

Computational Materials Science

Molecular dynamics simulation of hetero-phase interfaces
Stability of nanopores at rough interfaces
Stochastic kinetic mean field algorithm to model atomic transport in immiscible systems

Fundamental Materials Physics and Atomic Transport

Work function of self-assembling monolayers

Nanostructured Materials

         Phase separation in wire structures
         Fabrication of sharply-segmented Cu/Nb/Cu Nanowires
         Nano-Multilayers for joining technologies
         Nanochemistry of the Half Heusler TiNiSn

High Resolution Material Analysis

Atom probe analysis of polymer/ceramic compounds
Organic molecules and biological structures in atom probe tomography
Catalysis by metallic wires

(As of 2017/2018)

Information and consulting:
Prof. Dr. Guido Schmitz (Tel: (0711) 685 61902, )

________________

Computational Materials Science

Molecular dynamics simulation of hetero-phase interfaces. The chemical structure and thickness of the interface in Ag/Cu or Ni/Au bilayers at different temperatures will be calculated by simulations based on embedded atom potentials. The aim is to determine the width of the chemical transition and also the interfacial energy and, if possible, the entropy. Direct comparison with atom probe measurements should reveal the characteristic of the coefficient of the gradient energy in thermodynamics of inhomogeneous systems. (Supervisors: Sebastian Eich, Guido Schmitz)

Stability of nanopores at rough interfaces. If two material surfaces are pressed on each other, the surface roughness leaves a distribution of nanopores at the interface, which is important for the contact resistance and welding. We would like to understand how these nanopores become instable with increasing the pressure to the ultimate strength of the material. From measurements of the contact resistance done in our team, we presume that each pore size has its own critical stress. But how is the exact quantitative relation between pore size and stress? Molecular dynamics simulation will be performed to learn about nucleation of dislocations and the plastic flow around the pores of a few nanometers in diameter. (Supervisors: Sebastian Eich, Guido Schmitz)

Stochastic kinetic mean field algorithm to model atomic transport in immiscible systems. In immiscible systems, constituents do not diffuse into each other, rather they separate. Determination of the diffusion coefficient in such systems is rather challenging. A novel concept is being developed based on a kinetic mean field (KMF) approach supplemented with stochastic features by introducing dynamic Langevin noise. The result is a stochastic kinetic mean field model (SKMF) which gives similar results as a lattice kinetic Monte Carlo (KMC) simulation. To investigated the atomic redistribution of the constituents in the immiscible system, atomic simulations of multilayer structures are performed (C or C++). Atomic transport processes determined in the SKMF simulation will be compared to experimental results reported in literature to derive desired diffusion coefficients. (Supervisor: Gabor Csiszar)

 
Fundamental Materials Physics and Atomic Transport

 

Work function of self-assembling monolayers. Self-assembling molecule layers (SAM) are used in polymer electronics to adapt the band structure between polymers and contacting materials (metals, solid semiconductors). We would like to measure the influence of SAM on the work function of nanometric field emitters. Metallic tips (Pt, Au) of 30 nm radius are prepared by electro-polishing. The electron emission from these tips will be measured before and after coating with SAM molecules. Using the Fowler-Nordheim theory of field emission, the data will be evaluated to demonstrate the difference in the work function quantitatively. The work is done in cooperation with a scientist of the Sony laboratories in Stuttgart. (Supervisors: Guido Schmitz / Florian van Wrochem)

Nanostructured Materials

Phase separation in wire structures. Nanowires are intensively studied, because they could form design elements of future improved microelectronics. We would like to go a step further and elaborate internal structures within the nanowires themselves. Owing to the 1D structure of wires (long, very thin cylinder), we do expect a periodic stacking of decomposing phases. What is the periodicity of this stacking? The project will anneal alloyed NiCu nanowires in order to induce phase separation. TEM and APT investigation will determine the influence of the 1D geometry on the atomic transport and the developing phase structure. (Supervisors: Gabor Csiszar, Guido Schmitz)

Fabrication of sharply-segmented Cu/Nb/Cu Nanowires. Hetero-structured nanowires consisting of multiple segments of different materials may have a key role in future applications in electronics. Electrodeposition into porous membranes is a versatile method, which enables the fabrication 1D-like nano-architectures. In this study, we will investigate the crystalline orientation relationship between fcc Cu segments and bcc Nb segments. Will it follow the well-known Kurdjumov-Sachs relationship known in precipitation of bulk systems? The heterostructures formed within the nanowires are characterized by means of aberration corrected TEM techniques, aberration corrected scanning TEM (STEM), energy dispersive X-ray spectroscopy, and atom probe tomography. (Supervisor: Gabor Csiszar) 

Nano-Multilayers for joining technologies. A high interface to volume ratio can strongly reduce the melting temperature of materials. In this project we investigate multilayers of Cu4nm/AlN4nm to be used as a soldering “alloy”. Which process leads to the reduction of the melting temperature? How does Cu redistribute when the layers start melting. Multilayer samples will be analyzed by FIB/SEM and high resolution atom probe tomography. The project is done in cooperation with the EMPA /Zürich (Swiss materials testing institution) which delivers the samples. (Supervisors: Lars Jeurgens (EMPA), Guido Schmitz)

Nanochemistry of the Half Heusler TiNiSn (collaboration with A. Weidenkaff). The half Heusler alloy TiNiSn has a promising figure of merit in high temperature thermoelectric cells. The electrical and thermal conductivity is possibly controlled by nanometric precripitates. In a joint project with Anke Weidenkaff, we will produce thin films of this material and investigate their chemical homogeneity and decomposition on smallest length scales by latest atom probe tomography. (Supervisors: Guido Schmitz/Patrick Stender)

High Resolution Material Analysis

Atom probe analysis of polymer/ceramic compounds. Just a few years ago, only metallic samples could be analyzed by atom probe tomography (APT). By the innovative assistance of femto-second laser pulses, the method now can investigate also semiconductors and ceramics – and most recently shown by us – polymers. Now we want to go a step further: analyzing polymer/ceramic compounds as a model for biological materials which often represent ceramic-protein compounds. V2O5/poly-electrolyte multi-layers will be deposited in cooperation with the team of Prof. Bill. The structure of the inner interfaces will be analyzed for the first time with APT. (Supervisor: Patrick Stender)

Organic molecules and biological structures in atom probe tomography. By introducing laser-assisted field evaporation, we could recently demonstrate the analysis of polymeric materials even with atom probe tomography. In this project we want to embed interesting organic units (e.g. hemoglobin, ferritin or similar proteins) into a polymer matrix and then to evaporate both in a controlled fashion. The project has a pioneering character since on success, a microscopic chemical analysis of proteins or even DNA chains might become possible in future. (Supervisor: Patrick Stender)

Catalysis by metallic wires. In today’s catalytic converters, platinum is a key catalytic component to oxidize hazardous gases like CO and CxHx. To reduce the costs of the catalytic converters, it would be beneficial to use a Palladium/Platinum alloy instead of pure Pt. The addition of Pd will change the properties of the catalytic process and the stability of the catalytic component. Our goal is to investigate the oxidation of Pt/Pd alloy particles by atom probe tomography and to get an insight into the material changes during the catalytic process. (Supervisor: Yoonhee Lee, Guido Schmitz)

Where can you do research in a motivating environment? Implement your own ideas? In the field of Material Physics of course. Below are several current topic possibilities for your Master thesis:


 ______________ 

Computational Materials Science

Molecular dynamics simulation of hetero-phase interfaces
Stability of nanopores at rough interfaces
Stochastic kinetic mean field algorithm to model atomic transport in immiscible systems

Fundamental Materials Physics and Atomic Transport

Work function of self-assembling monolayers

Nanostructured Materials

         Phase separation in wire structures
         Fabrication of sharply-segmented Cu/Nb/Cu Nanowires
         Nano-Multilayers for joining technologies
         Nanochemistry of the Half Heusler TiNiSn

High Resolution Material Analysis

Atom probe analysis of polymer/ceramic compounds
Organic molecules and biological structures in atom probe tomography
Catalysis by metallic wires

(As of 2017/2018)

Information and consulting:
Prof. Dr. Guido Schmitz (Tel: (0711) 685 61902, )

________________

Computational Materials Science

Molecular dynamics simulation of hetero-phase interfaces. The chemical structure and thickness of the interface in Ag/Cu or Ni/Au bilayers at different temperatures will be calculated by simulations based on embedded atom potentials. The aim is to determine the width of the chemical transition and also the interfacial energy and, if possible, the entropy. Direct comparison with atom probe measurements should reveal the characteristic of the coefficient of the gradient energy in thermodynamics of inhomogeneous systems. (Supervisors: Sebastian Eich, Guido Schmitz)

Stability of nanopores at rough interfaces. If two material surfaces are pressed on each other, the surface roughness leaves a distribution of nanopores at the interface, which is important for the contact resistance and welding. We would like to understand how these nanopores become instable with increasing the pressure to the ultimate strength of the material. From measurements of the contact resistance done in our team, we presume that each pore size has its own critical stress. But how is the exact quantitative relation between pore size and stress? Molecular dynamics simulation will be performed to learn about nucleation of dislocations and the plastic flow around the pores of a few nanometers in diameter. (Supervisors: Sebastian Eich, Guido Schmitz)

Stochastic kinetic mean field algorithm to model atomic transport in immiscible systems. In immiscible systems, constituents do not diffuse into each other, rather they separate. Determination of the diffusion coefficient in such systems is rather challenging. A novel concept is being developed based on a kinetic mean field (KMF) approach supplemented with stochastic features by introducing dynamic Langevin noise. The result is a stochastic kinetic mean field model (SKMF) which gives similar results as a lattice kinetic Monte Carlo (KMC) simulation. To investigated the atomic redistribution of the constituents in the immiscible system, atomic simulations of multilayer structures are performed (C or C++). Atomic transport processes determined in the SKMF simulation will be compared to experimental results reported in literature to derive desired diffusion coefficients. (Supervisor: Gabor Csiszar)

 
Fundamental Materials Physics and Atomic Transport

 

Work function of self-assembling monolayers. Self-assembling molecule layers (SAM) are used in polymer electronics to adapt the band structure between polymers and contacting materials (metals, solid semiconductors). We would like to measure the influence of SAM on the work function of nanometric field emitters. Metallic tips (Pt, Au) of 30 nm radius are prepared by electro-polishing. The electron emission from these tips will be measured before and after coating with SAM molecules. Using the Fowler-Nordheim theory of field emission, the data will be evaluated to demonstrate the difference in the work function quantitatively. The work is done in cooperation with a scientist of the Sony laboratories in Stuttgart. (Supervisors: Guido Schmitz / Florian van Wrochem)

Nanostructured Materials

Phase separation in wire structures. Nanowires are intensively studied, because they could form design elements of future improved microelectronics. We would like to go a step further and elaborate internal structures within the nanowires themselves. Owing to the 1D structure of wires (long, very thin cylinder), we do expect a periodic stacking of decomposing phases. What is the periodicity of this stacking? The project will anneal alloyed NiCu nanowires in order to induce phase separation. TEM and APT investigation will determine the influence of the 1D geometry on the atomic transport and the developing phase structure. (Supervisors: Gabor Csiszar, Guido Schmitz)

Fabrication of sharply-segmented Cu/Nb/Cu Nanowires. Hetero-structured nanowires consisting of multiple segments of different materials may have a key role in future applications in electronics. Electrodeposition into porous membranes is a versatile method, which enables the fabrication 1D-like nano-architectures. In this study, we will investigate the crystalline orientation relationship between fcc Cu segments and bcc Nb segments. Will it follow the well-known Kurdjumov-Sachs relationship known in precipitation of bulk systems? The heterostructures formed within the nanowires are characterized by means of aberration corrected TEM techniques, aberration corrected scanning TEM (STEM), energy dispersive X-ray spectroscopy, and atom probe tomography. (Supervisor: Gabor Csiszar) 

Nano-Multilayers for joining technologies. A high interface to volume ratio can strongly reduce the melting temperature of materials. In this project we investigate multilayers of Cu4nm/AlN4nm to be used as a soldering “alloy”. Which process leads to the reduction of the melting temperature? How does Cu redistribute when the layers start melting. Multilayer samples will be analyzed by FIB/SEM and high resolution atom probe tomography. The project is done in cooperation with the EMPA /Zürich (Swiss materials testing institution) which delivers the samples. (Supervisors: Lars Jeurgens (EMPA), Guido Schmitz)

Nanochemistry of the Half Heusler TiNiSn (collaboration with A. Weidenkaff). The half Heusler alloy TiNiSn has a promising figure of merit in high temperature thermoelectric cells. The electrical and thermal conductivity is possibly controlled by nanometric precripitates. In a joint project with Anke Weidenkaff, we will produce thin films of this material and investigate their chemical homogeneity and decomposition on smallest length scales by latest atom probe tomography. (Supervisors: Guido Schmitz/Patrick Stender)

High Resolution Material Analysis

Atom probe analysis of polymer/ceramic compounds. Just a few years ago, only metallic samples could be analyzed by atom probe tomography (APT). By the innovative assistance of femto-second laser pulses, the method now can investigate also semiconductors and ceramics – and most recently shown by us – polymers. Now we want to go a step further: analyzing polymer/ceramic compounds as a model for biological materials which often represent ceramic-protein compounds. V2O5/poly-electrolyte multi-layers will be deposited in cooperation with the team of Prof. Bill. The structure of the inner interfaces will be analyzed for the first time with APT. (Supervisor: Patrick Stender)

Organic molecules and biological structures in atom probe tomography. By introducing laser-assisted field evaporation, we could recently demonstrate the analysis of polymeric materials even with atom probe tomography. In this project we want to embed interesting organic units (e.g. hemoglobin, ferritin or similar proteins) into a polymer matrix and then to evaporate both in a controlled fashion. The project has a pioneering character since on success, a microscopic chemical analysis of proteins or even DNA chains might become possible in future. (Supervisor: Patrick Stender)

Catalysis by metallic wires. In today’s catalytic converters, platinum is a key catalytic component to oxidize hazardous gases like CO and CxHx. To reduce the costs of the catalytic converters, it would be beneficial to use a Palladium/Platinum alloy instead of pure Pt. The addition of Pd will change the properties of the catalytic process and the stability of the catalytic component. Our goal is to investigate the oxidation of Pt/Pd alloy particles by atom probe tomography and to get an insight into the material changes during the catalytic process. (Supervisor: Yoonhee Lee, Guido Schmitz)