Native defects in monolayer GaS and GaSe: electrical properties and thermodynamic stability

TL;DR

This study uses ab-initio calculations to analyze native defects in monolayer GaS and GaSe, revealing their impact on electrical properties and stability, and suggesting growth conditions to minimize defect concentrations.

Contribution

It provides a detailed theoretical analysis of native defects in GaS and GaSe monolayers, highlighting their electrical behavior and stability, which was not previously well understood.

Findings

Native defects do not act as shallow dopants.

Native defects are efficient recombination centers.

Growth conditions can be optimized to reduce defect concentrations.

Abstract

Structural, electronic and thermodynamic properties of native defects in GaS and GaSe monolayers are investigated by means of accurate ab-initio calculations. Based on their charge transition levels we assess the influence of the studied defects on the electrical properties of the monolayers. Specifically, we show that native defects do not behave as shallow dopants and their presence cannot account for the experimentally observed intrinsic doping. In addition, we predict that native defects are efficient compensation and recombination centers. Besides pointing out their detrimental nature, we also calculate the corresponding finite temperature formation energies and provide a window of growth conditions able to reduce the concentration of all relevant native defects.