INITIAL OXIDATION STAGE OF THE GE(100)2X1 SURFACE STUDIED BY SCANNING-TUNNELING-MICROSCOPY AND ULTRA-VIOLET PHOTOELECTRON-SPECTROSCOPY

The initial stage of oxygen chemisorption on the Ge(100) surface and i ts annealing behavior were studied by scanning tunneling microscopy (S TM) and ultra-violet photoelectron spectroscopy (UPS). Atomically reso lved dark and bright sites were identified by the interaction at room- temperature exposure to molecular oxygen. These surfaces showed a prom inent peak at 4.6 eV in the UPS spectra. After annealing at 300 degree s C, the oxygen-induced products clustered along the dimer rows and fo rmed an aligned dark structure. Isolated bright products still remaine d, and some of them were the same as those on the room-temperature exp osure. UPS spectra showed a shift on the peak energy to 5.5 eV, indica ting that a stable Ge-O-Ge complex has been formed by the annealing. ( C) 1998 Elsevier Science B.V. All rights reserved.