2D graphitic-like gallium nitride and structural selectivity in confinement at graphene/SiC interface

TL;DR

This study demonstrates the experimental realization of a monolayer of graphitic-like GaN at a graphene/SiC interface, revealing structural selectivity driven by chemical bonding in confined environments.

Contribution

First experimental observation of buckled GaN monolayer in confinement at graphene/SiC interface, highlighting chemical bond influence on structure.

Findings

GaN monolayer obtained via MOCVD in confinement.

Discontinuity in stacking sequence due to Ga-O bond formation.

Chemical bonds influence structural selectivity at atomic scale.

Abstract

Predictive first-principles calculations suggest graphitic-like GaN to be theoretically possible. Thus far, it has not been experimentally reported. We report on GaN monolayer in a buckled geometry obtained in confinement at graphene/SiC interface by metalorganic chemical vapor deposition (MOCVD). Conductive atomic force microscopy (C-AFM) has been employed to probe vertical current injection through the graphene/SiC interface and to establish the uniformity of the intercalated areas. Scanning transmission electron microscopy (S/TEM) has been employed for atomic resolution imaging and spectroscopy. Discontinuity in the anticipated stacking sequence of graphitic-like GaN monolayers has been exposed and reasoned as a case of simultaneous formation of Ga-N and Ga-O bonds. The formation of Ga-O bonds acquires importance in instigating chemical-species-specific structural selectivity in confinement at atom-size scale.