Alloying strategy for two-dimensional GaN optical emitters

TL;DR

This paper investigates alloying strategies for 2D GaN to tune its optical properties, revealing that phosphorous alloying can effectively reduce the band gap and enhance light-emitting capabilities.

Contribution

It introduces a first-principles approach to alloy 2D GaN with group V elements, demonstrating tunable band gaps and potential for optoelectronic applications.

Findings

Dilute P alloying reduces band gap efficiently

Alloying introduces disorder facilitating optical transitions

Lower energy penalty for P incorporation compared to bulk GaN

Abstract

The recent progress in formation of two-dimensional (2D) GaN by a migration-enhanced encapsulated technique opens up new possibilities for group III-V 2D semiconductors with a band gap within the visible energy spectrum. Using first-principles calculations we explored alloying of 2D-GaN to achieve an optically active material with a tuneable band gap. The effect of isoelectronic III-V substitutional elements on the band gaps, band offsets, and spatial electron localization is studied. In addition to optoelectronic properties, the formability of alloys is evaluated using impurity formation energies. A dilute highly-mismatched solid solution 2D-GaN$_{1-x}$P$_x$ features an efficient band gap reduction in combination with a moderate energy penalty associated with incorporation of phosphorous in 2D-GaN, which is substantially lower than in the case of the bulk GaN. The group-V alloying elements also introduce significant disorder and localization at the valence band edge that facilitates direct band gap optical transitions thus implying the feasibility of using III-V alloys of 2D-GaN in light-emitting devices.