Oxidation of CoGa(110)

The interaction of oxygen (O-2) with CoGa(110) has been studied by means of high-resolution electron energy loss spectroscopy (EELS), low energy elect ron diffraction (LEED) and Auger electron spectroscopy (AES). At 300 K, an amorphous Ga oxide grows, which transforms into an ordered structure at 770 K. A thin well-ordered Ga oxide layer also grows at this ordering temperat ure. The LEED pattern of the well-ordered Ga oxide corresponds to a structu re with small distortion from a hexagonal arrangement. The EEL spectrum exh ibits four losses at 305, 470, 605 and 745 cm(-1) which are characteristic for Ga2O3. The EEL spectrum can be reproduced by calculations based on the dielectric theory by using IR parameters of Ga2O3. The thickness of the fil m is estimated to be about 10 Angstrom. (C) 2000 Elsevier Science B.V. All rights reserved.