Phonon-Assisted Photoluminescence and Exciton Recombination in Monolayer Aluminum Nitride

TL;DR

This paper demonstrates that monolayer hexagonal aluminum nitride exhibits strong UV photoluminescence facilitated by phonon-assisted indirect bandgap recombination, offering promising potential for UV optoelectronic devices.

Contribution

The study reveals phonon-assisted photoluminescence in monolayer AlN, highlighting its potential as an efficient UV light emitter in optoelectronic applications.

Findings

Strong UV photoluminescence in AlN monolayers

Phonon modes facilitate indirect bandgap recombination

Potential for UV optoelectronic device development

Abstract

Efficient solid-state photon emitters with longer operating lifetimes in the ultraviolet (UV) wavelength range are crucial for optoelectronic devices. However, finding suitable material candidates has been a significant challenge. Here, we demonstrate that hexagonal aluminum nitride (AlN) monolayers exhibit strong photoluminescence emission within the UV range of 3.94 - 4.05 eV. We show that these emissions in indirect bandgap AlN are facilitated by phonon modes with finite lattice momentum. These phonon modes promote efficient recombination of electrons and holes from the $\Gamma$ to K point of the Brillouin zone. Our findings provide a foundation for developing advanced optoelectronic devices and efficient UV light sources based on hexagonal AlN monolayers.