FUNCTIONAL PROPERTIES OF PIEZOELECTRIC THIN FILMS

This Bachelors/Masters assignment is for those who are interested in piezoelectric thin films.

The goal is to measure functional properties of piezoelectric thin films with different microstructures. It is also of interest to measure and analyze the functional properties of the film with an applied bias field, and comparing the results to the previously developed model.

For more information and contact details click on the following link: https://www.utwente.nl/en/tnw/xuv/thesis-assignments/Functional%20properties%20of%20piezoelectric%20thin%20films/

Detecting hydrogen from the sputtered ion signal in low-energy ion scattering

Low-energy ion scattering (LEIS) probes the outermost atomic layer of a surface by backscattering of noble gas ions. Under certain conditions, also depth profiles up to 5–10 nm depth can be obtained. LEIS spectra of hydrogen containing samples have a background signal at the low energy side of the spectrum due to hydrogen atoms that are sputtered away and ionised by the noble gas ions used for probing the sample. Time-of-Flight (TOF) measurements can separate the hydrogen ion signal from other sputtered elements and backscattered ions. A previous bachelor student project has shown that the thus obtained hydrogen signal is indeed proportional to the hydrogen content of the sample. In this assignment, the focus will be on a better understanding of the detection depth of hydrogen by LEIS, the possibilities for quantification and the detection of hydrogen in sputter depth profiles.


LEIS spectra of clean and hydrogen exposed Pd. The red and blue line show the signal of backscattered He+ ions for Pd cleaned by Ar ion sputtering and after exposure to H atoms, respectively. The green line shows the signal due to sputtered H ions.

Contact: Dr. Marko Sturm (j.m.sturm@utwente.nl), or contact prof.dr.Marcelo Ackermann.

Spectral Unraveling (SUN) of EUV light sources

A broadband transmission grating spectrometer approach

The XUV Optics group is undertaking an exciting project based on a newly developed optical component: a nanoscale patterned transmission grating that enables high resolution spectroscopy. The project goal is to do a comprehensive spectral characterization of EUV sources, through measurement of source spectrum in a broad wavelength range, from EUV to visible. Industry has shown interest and a recent grant was received for further optical and technological development of spectrometers. Currently a wealth of spectroscopic data is being gathered from several EUV sources including the most powerful industrial sources in the world.

The goal in this assignment (BSc or MSc) can be designing of new gratings or developing methods for retrieval of the emitted spectra from measurements. A particular challenge in the retrieval is the overlap of several diffraction orders of the grating and contribution of the noise. Candidate solutions include a first method to stitch spectra retrieved from 1st order measurements with several bandpass filters, and a second method to remove all higher order diffraction contributions from measured spectrum. In this project, you can gain experience in principles of spectrometers and spectroscopic analysis.

Contact: Dr. Muharrem Bayraktar (m.bayraktar@utwente.nl) , or contact prof.dr.Marcelo Ackermann.