Title: Electronic and Optical Properties of Two-Dimensional GaN from First-Principles

Abstract

Gallium nitride (GaN) is a vital commercial semiconductor for solid-state lighting applications. Atomically thin GaN, a recently synthesized two-dimensional material, is of particular interest because the extreme quantum confinement enables additional control of its light-emitting properties. We performed first-principles calculations based on density functional and many-body perturbation theory to investigate the electronic, optical, and excitonic properties of monolayer and bilayer two-dimensional (2D) GaN as a function of strain. These findings demonstrate that light emission from monolayer 2D GaN is blueshifted into the deep ultraviolet range, which is promising for sterilization and water-purification applications. Light emission from bilayer 2D GaN occurs at a similar wavelength to its bulk counterpart due to the cancellation of the effect of quantum confinement on the optical gap by the quantum-confined Stark shift. Polarized light emission at room temperature is possible via uniaxial in-plane strain, which is desirable for energy-efficient display applications. We compare the electronic and optical properties of freestanding two-dimensional GaN to atomically thin GaN wells embedded within AlN barriers in order to understand how the functional properties are influenced by the presence of barriers. Our results offer microscopic understanding of the electronic and optical characteristics of GaN at the few-layer regime.

Authors:

Sanders, Nocona  ^[1];

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Bayerl, Dylan ^[1]; Shi, Guangsha ^[1]; Mengle, Kelsey A. ^[1]; Kioupakis, Emmanouil ^[1]

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1. Univ. of Michigan, Ann Arbor, MI (United States)

Publication Date:

Wed Oct 25 00:00:00 EDT 2017

Research Org.:

Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). National Energy Research Scientific Computing Center (NERSC)

Sponsoring Org.:

USDOE; National Science Foundation (NSF)

OSTI Identifier:

1484740

Grant/Contract Number:  

AC02-05CH11231

Resource Type:

Accepted Manuscript

Journal Name:

Nano Letters

Additional Journal Information:

Journal Volume: 17; Journal Issue: 12; Journal ID: ISSN 1530-6984

Publisher:

American Chemical Society

Country of Publication:

United States

Language:

English

Subject:

36 MATERIALS SCIENCE; GaN; electronic structure; optical properties; first-principles calculations; two-dimensional materials