Abstract
We have studied the oxidation of layered compound GaSe with no dangling bonds on the cleaved surface using XPS and AES techniques. At room temperature, the cleaved surface is not oxidized in an oxygen atmosphere. When subjected to Ar ion sputtering, the surface starts to exhibit the behavior of metallic Ga owing to dissipation of the first sublayer of Se in the primitive layer, Se–Ga–Ga–Se. The thin layer of metallic Ga thus exposed is easily oxidized. In the thermal oxidation of cleaved GaSe in air, the oxygen diffuses into the primitive layer and combines with Ga, severing the intralayer bonding between the Se and Ga atoms. At temperature higher than 450°C, the oxygen is also intercalated between the primitive layers from the sides perpendicular to the layers. No Se oxides are observed under any of the oxidation conditions.