title: 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.
authors: Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, USA.|Center for 2-Dimensional and Layered Materials, The Pennsylvania State University, University Park, Pennsylvania 16802, USA.
authors: Zakaria Y
authors: ZY
authors: Al Balushi
authors: Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802, USA.
authors: Ke
authors: K
authors: Wang
authors: Department of Electrical Engineering, University of Norte Dame, Notre Dame, Indiana 46556, USA.|Department of Electrical Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, USA.
authors: Ram Krishna
authors: RK
authors: Ghosh
authors: Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, USA.|Center for 2-Dimensional and Layered Materials, The Pennsylvania State University, University Park, Pennsylvania 16802, USA.
authors: Rafael A
authors: RA
authors: Vilá
authors: Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, USA.|Center for 2-Dimensional and Layered Materials, The Pennsylvania State University, University Park, Pennsylvania 16802, USA.|Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802, USA.
authors: Sarah M
authors: SM
authors: Eichfeld
authors: US Naval Research Laboratory, Washington DC 20375, USA.
authors: Joshua D
authors: 0000-0003-0374-2168
authors: JD
authors: Caldwell
authors: Department of Materials Science and Engineering, The University of Texas at Dallas, Richardson, Texas 75080, USA.
authors: Xiaoye
authors: X
authors: Qin
authors: Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, USA.|Center for 2-Dimensional and Layered Materials, The Pennsylvania State University, University Park, Pennsylvania 16802, USA.
authors: Yu-Chuan
authors: YC
authors: Lin
authors: US Naval Research Laboratory, Washington DC 20375, USA.
authors: Paul A
authors: PA
authors: DeSario
authors: Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, USA.|Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802, USA.
authors: Greg
authors: G
authors: Stone
authors: Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, USA.|Center for 2-Dimensional and Layered Materials, The Pennsylvania State University, University Park, Pennsylvania 16802, USA.
authors: Shruti
authors: S
authors: Subramanian
authors: Physical Electronics USA, 18725 Lake Drive East, Chanhassen, Minnesota 55317, USA.
authors: Dennis F
authors: DF
authors: Paul
authors: Department of Materials Science and Engineering, The University of Texas at Dallas, Richardson, Texas 75080, USA.
authors: Robert M
authors: RM
authors: Wallace
authors: Department of Electrical Engineering, University of Norte Dame, Notre Dame, Indiana 46556, USA.|Department of Electrical Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, USA.
authors: Suman
authors: S
authors: Datta
authors: Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, USA.|Center for 2-Dimensional and Layered Materials, The Pennsylvania State University, University Park, Pennsylvania 16802, USA.|Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802, USA.|Department of Electrical Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, USA.
authors: Joan M
authors: JM
authors: Redwing
authors: Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, USA.|Center for 2-Dimensional and Layered Materials, The Pennsylvania State University, University Park, Pennsylvania 16802, USA.|Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802, USA.
authors: Joshua A
authors: JA
authors: Robinson