Structural and optical properties of InAs/AlAsSb quantum dots with GaAs(Sb) cladding layers

Abstract

We investigate the effect of GaAs1−xSbx cladding layer composition on the growth and properties of InAs self-assembled quantum dots surrounded by AlAs0.56Sb0.44 barriers. Lowering Sb-content in the GaAs1−xSbx improves the morphology of the InAs quantum dots and reduces cladding layer alloy fluctuations. The result is a dramatic increase in photoluminescence intensity from the InAs quantum dots, with a peak at 0.87 eV. The emission energy exhibits a cube root dependence on excitation power, consistent with the type-II band alignment of the quantum dots. The characteristics of this quantum dot system show promise for applications such as intermediate band solar cells.