High-resolution measurements of electrons scattered from surfaces at high energies (up to 40 keV) provide information on the sample composition, electronic structure and crystal structure. These measurements have only become possible over the last few years with the development of a home-build high-resolution spectrometer in our laboratory. We are in the process of unravelling the information contained in these spectra, and the interpretation reveals an unexpected array of phenomena. The obtained understanding is highly relevant for high-energy X-ray photoemission, electron microscopy, and even neutron scattering. The long-term goal is to develop an electron spectroscopic tool for the analysis of surface layers of intermediate thickness that can be integrated in an electron microscope.
W.S.M. Werner and M. R. Went and M. Vos, and K. Glantschnig and C. Ambrosch-Draxl, Measurement and Density Functional Calculations of Optical Constants of Ag and Au from Infrared to VUV Wavelengths, Physical Review B 77 161404 (2008).
A. Winkelmann and M. Vos, Site-Specific Recoil Diffraction of Backscattered Electrons in Crystals, Phys. Rev. Lett. 106 ,085503 (2011).
M. Vos, K. Tokesi and I Benko, The potential of materials analysis by electron Rutherford backscattering as illustrated by a case study of mouse bones and related compounds Microscopy and Microanalysis 19 , 576 (2013).
P. Grande, M. Vos, M. D. Venkatachalam S.Nandi and R. Elliman, Determination of thickness and composition of high-k dielectrics using high-energy electrons, Applied Physics Letters 103 , 071911 (2013).
Oxygen Self-Diffusion in HfO2 Studied by Electron Spectroscopy
M. Vos, P.L. Grande,D. Venkatachalam, et al. Phys. Rev. let. 112 175901 (2014)
The projectc can be taylored to the interests and knowledge of the student. There are opportunities in spectrometer development, automatisation, interpretation of spectra, and the theory of the propagation of keV electrons in matarials.