Comment on "Investigation on optical properties of ZnO nanowires by electron energy-loss spectroscopy".
Recently, Zhang et al. have published a paper [Zhang, Z.H., Qi, X.Y., Jian, J.K., Duan, X.F., 2006. Micron 37, 229-233] in which - among others - the determination of the optical properties of a semiconductor by use of electron energy-loss spectroscopy (EELS) is performed with 200 keV electrons and a collection angle of only 0.3 mrad. The authors do not take into account relativistic effects such as Cerenkov losses (CL) before performing Kramers-Kronig Analysis (KKA) on the EELS spectra obtaining erroneous results. Although the positions of features within the optical properties are consistant with the simulated ones, the relative hights or absolute values differ a lot.
Stöger-Pollach
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University Service Center for Transmission Electron Microscopy, Technische Universität Wien, Wiedner Hauptstrasse 8-10, A-1040 Wien, Austria. stoeger@ustem.tuwien.ac.at
Galek
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