Construction of two-dimensional lateral heterostructures by graphenelike ZnO and GaN monolayers for potential optoelectronic applications

Abstract

Constructing lateral heterostructures (LHSs) is a promising strategy to provide a new pathway to broaden the applications in nanoelectronic and nanospintronic devices. Herein, the influence of the width and strain engineering as well as vacancy defects on the electronic structures and magnetic properties of ZnO/GaN LHSs is systematically investigated by the first-principles calculations. The results show that zigzag- or armchair-(ZnO)m/(GaN)m LHSs undergo the type-I to quasi type-II band transition when the width m increases from 4 to 12. However, once m is greater than 12, zigzag LHSs exhibits metallic character. Zigzag LHSs experience a direct-to-indirect semiconducting-to-metallic transition with increasing of width m (4 ≤ m ≤ 20). The armchair-(ZnO)12/(GaN)12 LHSs with the bandgap of 1.794 eV present thermally and dynamically stable, exhibiting type-II band alignment. Moreover, armchair-(ZnO)12/(GaN)12 LHSs behaves excellent optical absorption performance in visible light range. Furthermore, a transition from type-I to quasi type-II band alignment appears in armchair-(ZnO)12/(GaN)12 LHSs when the strains are applied. Additionally, the magnetic properties of armchair-(ZnO)12/(GaN)12 LHSs can be effectively modulated by introducing vacancy defects. Armchair-(ZnO)12/(GaN)12 LHSs with VO maintains the semiconducting character, and (ZnO)12/(GaN)12 LHSs with VZn, VN and VGa exhibit semi-metallic feature with the total magnetic moments within 1∼3 μB. The current results provide vital guidance for the investigation and modulation of electronic properties of ZnO/GaN LHSs, thereby broadening the possibility of facilitating the potential applications for potential nano-optoelectronics devices.