Surface topology of GaSe oxidized crystals

Changes in the surface topology of GaSe crystals caused by their oxidization are investigated by the atomic force microscopy method. The nucleation of a new phase of Ga2O3 intrinsic oxide takes place due to the formation of close arrays of nanoneedles precisely oriented normally to the GaSe surface. The temperature and duration of the oxidization process influences on form, sizes, and transformation of nanoneedles. Their sizes change insignificantly in the temperature range 400 to 600 ∘C and for an oxidation time of 1 to 4 h. The average dimension of the nanoneedles’ bases is in the range 50–60 nm and their height increases from 0.5 to 3.5 nm with increasing temperature. The increase of the oxidation temperature also leads to clusterization of nanoneedles in the form of a grid-type structure. The cells of such structure have arbitrary forms and their sizes considerably exceed those of nanoneedles.