2D Nitride Ordered Alloys: A Novel Class of Ultra-Wide Bandgap Semiconductors

TL;DR

This paper explores the stability and electronic properties of novel 2D ultra-wide bandgap nitride alloys, revealing stable structures with unique polar and antiferroelectric properties through ab initio calculations.

Contribution

It introduces a new class of 2D BxM1-xN alloys with stable structures and novel out-of-plane displacements, expanding the understanding of UWBG materials.

Findings

Identified stable 2D BxM1-xN structures via ab initio calculations.

Discovered out-of-plane puckering induces polar and antiferroelectric states.

Lowered energy barriers enable switching between ferroelectric states.

Abstract

Ultra-wide bandgap (UWBG) semiconductors are poised to transform power electronics by surpassing the capabilities of established wide bandgap materials, such as GaN and SiC, owing to their capability to operate at higher voltage, frequency, and temperature ranges. While bulk group-III nitrides and their alloys have been extensively studied in the UWBG realm, their two-dimensional counterparts remain unexplored. Here, we examine the stability and electronic properties of monolayers of ordered boron-based group-III nitride alloys with general formula BxM1-xN, where M = Al, Ga. On the basis of ab initio calculations we identify a number of energetically and dynamically stable structures. Instrumental to their stability is a previously overlooked out-of-plane displacement (puckering) of atoms, which induces a polar ordering and antiferroelectric ground state. Our findings reveal the energy barrier between metastable ferroelectric states is lowered by successive switching of out-of-plane displacements through an antiferroelectric state.