Photoluminescence pressure coefficients of InAs/GaAs quantum dots

TL;DR

This study investigates how the band-gap pressure coefficients of InAs/GaAs quantum dots vary with shape, size, and alloying, revealing nonlinear effects and universal relationships that align with experimental data.

Contribution

It provides a detailed atomistic analysis of pressure coefficients in quantum dots, highlighting nonlinear effects and establishing universal relationships.

Findings

Reductions in band gap pressure coefficients compared to bulk materials.

Nonlinear pressure coefficients due to bulk InAs and GaAs properties.

Universal pressure coefficient versus band gap relationship.

Abstract

We have investigated the band-gap pressure coefficients of self-assembled InAs/GaAs quantum dots by calculating 17 systems with different quantum dot shape, size, and alloying profile using atomistic empirical pseudopotential method within the ``strained linear combination of bulk bands'' approach. Our results confirm the experimentally observed significant reductions of the band gap pressure coefficients from the bulk values. We show that the nonlinear pressure coefficients of the bulk InAs and GaAs are responsible for these reductions. We also find a rough universal pressure coefficient versus band gap relationship which agrees quantitatively with the experimental results. We find linear relationships between the percentage of electron wavefunction on the GaAs and the quantum dot band gaps and pressure coefficients. These linear relationships can be used to get the information of the electron wavefunctions.