Photoluminescence study of hydrogenated aluminum oxide–semiconductor interface

We present a study of oxide–semiconductor interfaces formed by wet thermal oxidation of a thin epitaxial AlAs layer. Photoluminescence (PL) from a quantum well in close proximity to the interface is monitored before and after oxidation. The normalized PL intensity was found to decrease roughly in proportion to the degree of completeness of the oxidation. The diminishing luminescence is attributed to the presence of trap states formed at the oxide–semiconductor interface formed during the oxidation process; hydrogen ion treatment is effective in the partial restoration of the luminescence. In addition to the traps, the oxidation process also “disorders” the material within ∼15 nm from the semiconductor–oxide interface, as revealed by transmission electron micrographs.