Electronic structure of InAs quantum dots with GaAsSb strain reducing layer: Localization of holes and its effect on the optical properties

TL;DR

This study investigates the electronic structure of InAs quantum dots with GaAsSb strain reducing layers, revealing hole localization effects and their impact on optical properties, including photoluminescence shifts and potential experimental identification methods.

Contribution

It provides a detailed theoretical analysis of hole localization in InAs quantum dots with GaAsSb layers and explains experimental photoluminescence shifts using k.p theory.

Findings

Holes are localized near the dot base for y>0.19 in GaAsSb layers.

Piezoelectric fields create molecular-like states at the dot sides.

Proposed experiment to identify hole localization using vertical electric field.

Abstract

The electronic structure of InAs quantum dots covered with the GaAs(1-y)Sb(y) strain reducing layer has been studied using the k.p theory. We explain previous experimental observations of the red shift of the photoluminescence emission with increasing y and its blue shift with increasing excitation power. For y>0.19 type-II dots are formed with holes localized in the GaAsSb close to the dot base; two segments at opposite sides of the dot, forming molecular-like states, result from the piezoelectric field. We also propose an experiment that could be used to identify the hole localization using a vertical electric field.