VOx ultrathin epitaxial films (0.8 less than or equal to x less than or equ
al to 1.3) have been grown on Pt(1 1 1) by evaporating vanadium in a low an
d well-controlled water background (1 x 10(-7) Pa). X-ray photoelectron spe
ctroscopy, ultraviolet photoelectron spectroscopy and X-ray excited auger e
lectron spectroscopy data strongly indicate that vanadium(II) in the predom
inant oxidation state. Angle-scanned photoelectron diffraction data are com
patible with a single domain film, bearing a rock-salt VO structure and exp
osing the (1 1 1) plane. Such films evolve toward more oxidized species wit
hin hours, probably due to oxidation by residual water in the chamber. (C)
2001 Elsevier Science B.V. All rights reserved.