Photoemission of the Oxidation of Cerium Overlayers on GaSb(110) Surface

We have used x-ray photoelectron spectroscopy to study the oxidation of cerium overlayers on a semiconductor GaSb(110) surface. A GaSb (110) sample covered with 10 monolayers Ce was used to adsorb oxygen. When the exposure of O₂ was up to 50L, the oxide of cerium, Ce₂O₃, began to change into unstable CeO₂. The dissociation of CeO₂ resulted in strong oxidation of the substrate. The main products are Ga₂O₃, Sb₂O₃, and then Sb₂O₅. After annealing, a part of the oxygen atoms transferred from cerium dioxide toward Ga and Sb.