Effect of strain on band alignment of GaAsSb/GaAs quantum wells

Abstract

GaAsSb/GaAs quantum wells are of great interest for optical communications; however, their band alignment properties are not fully understood, particularly at 35% Sb alloy concentration used for emission at 1.3 μm. We use device simulation methods based on the 8 × 8 k·p theory to explore the effects of GaAsSb/GaAs quantum well composition, width, and strain on the band alignment. Strain-relaxed wells demonstrate type-I alignment and pseudomorphic wells demonstrate type-II alignment, regardless of quantum-well composition or thickness for wells wider than 3 nm. For partially strain-relaxed wells, we determine the band alignment as a function of the interplay of composition, width, and strain. Our calculated results at various strain conditions agree well with published experimental data. This work provides insight on band alignment of GaAsSb/GaAs quantum wells, as well as of embedded quantum dots with strong confinement along the out-of-plane direction.