Graphene stabilization of two-dimensional gallium nitride

TL;DR

This paper reports the successful synthesis and stabilization of two-dimensional gallium nitride (GaN) using a novel graphene-assisted growth technique, revealing structural differences from theoretical models and emphasizing graphene's stabilizing role.

Contribution

It introduces a new migration-enhanced encapsulated growth method for 2D GaN and demonstrates graphene's critical role in stabilizing its structure and electronic properties.

Findings

2D GaN synthesized via MEEG differs from theoretical predictions

Graphene stabilizes the buckled, direct-bandgap structure of 2D GaN

Experimental validation of 2D GaN's electronic properties

Abstract

The spectrum of two-dimensional (2D) materials beyond graphene offers a remarkable platform to study new phenomena in condensed matter physics. Among these materials, layered hexagonal boron nitride (hBN), with its wide bandgap energy (~5.0-6.0 eV), has clearly established that 2D nitrides are key to advancing novel devices1. A gap, however, remains between the theoretical prediction of 2D nitrides beyond hBN and experimental realization of such structures. Here we demonstrate the synthesis of 2D gallium nitride (GaN) via a novel migration-enhanced encapsulated growth (MEEG) technique utilizing epitaxial graphene. We theoretically predict and experimentally validate that the atomic structure of 2D GaN grown via MEEG is notably different from reported theory. Moreover, we establish that graphene plays a critical role in stabilizing the direct-bandgap (nearly 5.0 eV), 2D buckled structure. Our results provide a foundation for discovery and stabilization of novel 2D nitrides that are difficult to prepare via traditional synthesis.