Two-dimensional gallium nitride realized via graphene encapsulation

Abstract

The spectrum of two-dimensional (2D) and layered 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 2D devices. 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 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 2D nitrides that are difficult to prepare via traditional synthesis.

Ultrawide‐Bandgap Semiconductors: Research Opportunities and Challenges

“…For thin semiconductors where quantum confinement and bandgap widening occurs, this is extremely important. Indeed, the WBG and UWBG semiconductors have recently sprung a few surprises in the limit of extreme thinness: 2D GaN and quasi-2D Ga 2 O 3 have been fabricated by sublimation or mechanical exfoliation, respectively, [133,179] potentially enabling significant increases in energy gap as fewer monolayers of material are isolated (e.g., 5.28 eV for 2D GaN). These ultrawide bandgaps, comparable even to the 5-6 eV of h-BN, will likely motivate research in advanced techniques for layer-by-layer epitaxial growth of both WBG and UWBG semiconductors.…”

Optical properties of single-layer and bilayer arsenene phases

“…The intriguing structural, electronic, and optical properties of many two-dimensional (2D) materials similar to graphene such as the transition-metal dichalcogenides [1][2][3], group IV elements [4,5], and group III-V based 2D materials [6][7][8] have motivated further research for new discoveries. Owing to its attractive intrinsic properties such as high carrier mobility, direct band gap, and superior optical properties, phosphorene has been widely in focus [9][10][11][12].…”

Brief Review of Epitaxy and Emission Properties of GaSb and Related Semiconductors

“…To date, two-dimensional GaN has been grown by a migration-enhanced encapsulated growth technique that uses epitaxial graphene [104]. Additionally, As-and Sb-based two-dimensional materials, called arsenene and antimonene, respectively, have been synthesized [105].…”