Observation of GaSe–SnO2 Heterostructure by XPS and AES

The depth profile of the elemental composition of the GaSe–SnO2 heterostructure has been studied by XPS and AES. The SnO2 layer was prepared by spraying a solution of SnCl4 and SbCl3 in ethyl alcohol on to the the cleaved surface of GaSe heated to ∼400°C in air. After the solution had been sprayed on for about 5 secs., an SnO2 layer of thickness ∼460 Å formed, and a Ga2O3 layer of thickness ∼120 Å formed under the SnO2 layer. The Ga2O3 layer is a likely origin of the high-resistivity layer observed in the GaSe–SnO2 heterostructure.