Effect of oxygen on the electronic configuration of Gd2O3/Ge heterojunctions

The band structure of the Gd2O3/Ge heterojunction was investigated by x-ray photoelectron spectroscopy and was found to be very sensitive to variations of oxygen content in the oxide film. A 0.6 eV decrease of the valence band offset (VBO) has been observed after in situ O-2 postdeposition annealing (PDA). The VBO value obtained after PDA is 2.8 eV in excellent agreement with data reported in the literature. The extra oxygen, supplied during PDA, is stably incorporated in the Gd2O3 matrix. Moreover, this extra oxygen limits moisture adsorption during air exposure and helps to stabilize the electronic configuration of the Gd2O3/Ge heterojunction. (c) 2008 American Institute of Physics.