BAlGaN alloys nearly lattice-matched to AlN for efficient UV LEDs

TL;DR

This study uses hybrid density functional theory to explore BAlGaN alloys, which can nearly match AlN's lattice and offer suitable band gaps, potentially improving UV LED efficiency.

Contribution

It demonstrates that BAlGaN alloys can be lattice-matched to AlN and have desirable electronic properties for UV LEDs, a novel approach for material design.

Findings

BAlGaN can lattice match AlN with appropriate composition.

BAlGaN alloys have band gaps suitable for UV emission.

BAlGaN emits transverse-electric polarized at higher gallium content.

Abstract

The lattice mismatch between AlGaN and AlN substrates limits the design and efficiency of UV LEDs, but it can be mitigated by the co-incorporation of boron. We employ hybrid density functional theory to investigate the thermodynamic, structural, and electronic properties of BAlGaN alloys. We show that BAlGaN can lattice match AlN with band gaps that match AlGaN of the same gallium content. We predict that BAlGaN emits transverse-electric polarized for gallium content of ~45% or more. Our results indicate that BAlGaN alloys are promising materials for higher efficiency UV optoelectronic devices on bulk AlN substrates.