Thermal oxidation of amorphous GaSe thin films

In this work the results of the thermal oxidation of GaSe thin films in air at different temperatures are presented. The structural and morphological characteristics of the thermally annealed products were studied by X-ray diffraction (XRD), Raman spectroscopy and scanning electron microscopy (SEM). The as-deposited GaSe films were amorphous and they transformed into polycrystalline GaSe films with a hexagonal crystal structure at a temperature around 400 degrees C. Thermal oxidation at 650 degrees C resulted in the formation of mixed Ga2Se3 and Ga2O3 compounds both in the monoclinic phase. At higher temperatures, Ga2Se3 disappeared and complete oxidation of the initial compound occurred. The optical energy gaps of products were determined at room temperature by transmittance measurements using UV-vis-NIR spectroscopy. (C) 2012 Elsevier Ltd. All rights reserved.