Semester Projects

(can be adapted to Bachelor or Master level)

Validation of theoretically calculated EELS spectra with OCEAN package

Electron energy loss spectroscopy (EELS) is a powerful technique, which provides information on the electronic structure of a material regardless of its state (crystalline, amorphous, liquid etc.). Due to the complex nature of the electron and matter interactions, quantum-mechanical calculations are needed to model the EEL spectra. OCEAN is a simulation package, which in conjugation with Quantum Espresso (density functional theory code developed in EPFL), offers a highly sophisticated approach on calculating absorption and EELS spectra and it allows to capture both – highly local atomic effects and effects due to the extended electronic structure of the material. The student will perform theoretical EELS calculations for several classes and types of materials, compare calculated spectra with experimental spectra (obtained through literature), and find the strong and weak points of the OCEAN package approach. It is noted that the package works in LINUX environment.

Contact: Mr. Reinis Ignatans
Training of a model for content-aware restoration of electron microscopy images

Developments in neural networks and deep learning methods have led to a variety of applications for image treatment and analysis. Electron microscopy of sensitive materials, such as polymers or liquids, could benefit from new tools for denoising and image restoration when imaging at low electron dose is required to avoid degradation. This project aims at making use of the CSBdeep toolbox to define and train a neural network for content aware image restoration of in situ liquid TEM images of fuel cell electrodes. The student will be comparing different training schemes and assess their efficiency against competitive denoising methods. Basic knowledge in programming and python language is preferred..

Contact: Mr. Robin Girod
Prototyping a customized heating gas cell for real time TEM observations of fuel cell catalysts

Performance of Pt/C nanocatalysts for fuel cell cathodes have been shown to dramatically improve after an annealing step in ambient atmosphere. The mechanism of this improvement however remains poorly understood, and real time analysis of the chemical and structural modifications at the nanoscale would be beneficial. In situ heating TEM is a powerful technique to access such real time information but maintaining environmental conditions throughout the experiment is challenging. The aim of this project is to prototype a novel gas-cell enclosure compatible with a dedicated specimen holder for heating in the TEM, so that the sample can be kept in air and isolated from the column vacuum. The student will experiment with different configurations involving MEMS-based chips and evaluate their merits under operational conditions.

Contact: Mr. Tzu-Hsien Shen and Mr. Robin Girod
MEMs-based chips for in situ TEM applications

The aim of this project is to fabricate MEMS-based chips for in situ TEM applications such as biasing, heating, and electrochemistry. The student will be introduced to MEMS technologies such as photolithography, etching process, thin film deposition, etc. The process of the chip fabrication will take place in the cleanroom at the Center of Micronanotechnology (CMi). The student is expected to understand the fundamentals of MEMS technologies and obtain hands-on experience of semiconductor processing. The MEMS processing skills obtained after this project are highly transferable especially in semiconductor industries. Previous hands-on experience in cleanroom is preferred for this project.

Contact: Mr. Jan Vavra and Mr. Tzu-Hsien Shen
Simulation of electric field distribution in TEM liquid cells for electrochemical analyses

Liquid-phase electron microscopy is a particularly interesting technique to study electrocatalytic reactions. However, the miniaturization of the electrochemical cell and the coplanar geometry of the electrodes in the liquid cell can make it difficult to quantitively compare the results between in situ and bulk experiments. To fill this gap, finite element simulations are proposed. The aim of this project is to develop a finite element model simulating an oxygen reduction reaction (ORR)/hydrogen oxidation reaction (HOR) experiments in an in situ TEM liquid cell. The student is expected to develop the model in COMSOL Multiphysics software, a commercial solution for finite element simulations.

Contact: Mr. Morgan Binggeli
In-situ detection of intermediates in electrochemical CO2 reduction reaction

Fluorescence spectroscopy is a highly sensitive method, perfect for detection of minute amounts of short-lived reaction intermediates. Aim of this project is to systematically investigate the effect of reaction parameters on the local concentration of an intermediate and further to understand its diffusion on the micrometer scale with the use of confocal microscopy. The project would be conducted partly at EPFL Lausanne and partly at EPFL Valais campus in Sion.

Contact: Mr. Jan Vavra
Design and precision 3D printing of custom liquid cell enclosures

To better understand processes within a thin liquid layer inside a MEMS device for closed cell environmental electron microscopy, it is beneficial to correlate the TEM data with other analytical techniques such as optical microscopy or synchrotron x-ray absorption and fluorescence spectroscopy or scanning electron microscopy. However, each method has specific requirements in terms of sample mounting and positioning. The goal of this project is to design custom enclosures for these devices in Catia or Solidworks. The enclosures concentrate liquid channels and electrical contacts to an area of several mm2 and make a reliable interface to the MEMS device. Prototypes will be precision 3D printed and their function evaluated.

Contact: Mr. Michele Bozzetti