CLEAN SURFACE AND OXIDATION BEHAVIOR OF VANADIUM CARBIDE, VC0.75(100)

The clean single-crystal VC0.75 (100) surface, its oxidation, and the stability of the resulting oxide were examined with electron spectrosc opy (AES, XPS and UPS), electron diffraction (low-energy and reflectio n high-energy electron diffraction) and atomic force microscopy (AFM). The clean VC0.75 surface exhibits carbon vacancy-related features in valence band spectroscopy data. This surface was exposed to O-2 at 500 degrees C for up to 10 000 Langmuirs. The oxidation leads to the form ation of vanadium oxide, VOx(100), crystallites on the VC0.75 (100) su bstrate. The AFM images indicate that oxide crystallites grow with an elongated shape along [001] type directions. When heated above 1000 de grees C, the oxide is unstable and a clean VC0.75 (100) surface is pro duced.