First-principles Predictions of Electronic Properties of GaAs1-x-yPyBix and GaAs1-x-yPyBix-based Heterojunctions

TL;DR

This study uses first-principles calculations to explore the electronic properties of a novel GaAs-based alloy with Bi and P, aiming to improve the efficiency of high-energy infrared LEDs and lasers by reducing Auger recombination.

Contribution

It provides a detailed theoretical analysis of GaAs1-x-yPyBix alloy's electronic properties and heterojunctions, highlighting their potential for high-efficiency optoelectronic devices.

Findings

GaAs1-x-yPyBix band gap is mainly affected by local structural changes.

Constraints on P and Bi compositions can lower Auger recombination.

GaAs/GaAs1-x-yPyBix heterojunctions show promising lattice matching and band offsets.

Abstract

Significant efficiency droop is a major concern for light-emitting diodes and laser diodes operating at high current density. Recent study has suggested that heavily Bi-alloyed GaAs can decrease the non-radiative Auger recombination and therefore alleviate the efficiency droop. Using density functional theory, we studied a newly fabricated quaternary alloy, GaAs1-x-yPyBix, which can host significant amounts of Bi, through calculations of its band gap, spin-orbit splitting, and band offsets with GaAs. We found that the band gap changes of GaAs1-x-yPyBix relative to GaAs are determined mainly by the local structural changes around P and Bi atoms rather than their electronic structure differences. To obtain alloy with lower Auger recombination than GaAs bulk, we identified the necessary constraints on the compositions of P and Bi. Finally, we demonstrated that GaAs/GaAs1-x-yPyBix heterojunctions with potentially low Auger recombination can exhibit small lattice mismatch and large enough band offsets for strong carrier confinement. This work shows that the electronic properties of GaAs1-x-yPyBix are potentially suitable for high-energy infrared light-emitting diodes and laser diodes with improved efficiency.