Hydrolyzation oxidation of Al<i>x</i>Ga1−<i>x</i>As-AlAs-GaAs quantum well heterostructures and superlattices

Abstract

Data are presented on the conversion (selective conversion) of high-composition (AlAs)x(GaAs)1−x layers, e.g., in AlxGa1−xAs-AlAs-GaAs quantum well heterostructures and superlattices (SLs), into dense transparent native oxide by reaction with H2O vapor (N2 carrier gas) at elevated temperatures (400 °C). Hydrolyzation oxidation of a fine-scale AlAs(LB)-GaAs(Lz) SL (LB +Lz≲100 Å), or random alloy AlxGa1−xAs (x≳0.7), is observed to proceed more slowly and uniformly than a coarse-scale ‘‘alloy’’ such as an AlAs-GaAs superlattice with LB + Lz≳200 Å.