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 0.6eV decrease of the valence band offset (VBO) has been observed after in situ O2 postdeposition annealing (PDA). The VBO value obtained after PDA is 2.8eV 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.
28 Jan 2008
Volume: 92 Issue: 4 Pages: 042106
Applied Physics Letters