UHV-Cleaved Single Crystal Cr2O3 (101¯2) by XPS and UPS

The oxides of chromium cover a wide stoichiometry range. There is a great deal of published x-ray photoelectron spectroscopy (XPS) data on Cr metal, where the goal is often identification of the oxide stoichiometry. In the last few years, thin Cr oxide films have also been grown epitaxially on other materials, and again the determination of stoichiometry is crucial. Presented here are Mg Kα XPS spectra taken from atomically clean, ultrahigh vacuum-cleaved, single crystal Cr2O3 (101¯2). The two largest peaks are the main Cr 2p3/2 and 2p1/2 lines, while the other features are satellites. The satellite structure is an important property of the oxide that may help to differentiate oxides of different stoichiometries. [See X. Li, V. E. Henrich, T. Saitoh, and A. Fujimori, Mater. Res. Soc. Symp. Proc. 307, 205 (1993).]