Chemical passivation of Si 111/ capped by a thin GaSe layer

An ultrathin layer of GaSe was grown on a hydrogen-terminated Si 111.substrate by molecular beam epitaxy. Substrate and epilayer were investigated by photoemission XPS and UPS.and electron diffraction LEED. immediately after sample preparation and after storage of 30 days in air. The tendency to surface oxidation is strongly reduced for the GaSe-covered sample compared to a hydrogen-terminated sample. q2000 Elsevier Science B.V. All rights reserved