类石墨烯单层结构ZnO和GaN的压电特性对比研究

Piezoelectricity of Graphene-like Monolayer ZnO and GaN

本研究采用基于密度泛函理论的第一性原理计算了类石墨烯单层结构ZnO(g-ZnO)和GaN(g-GaN)的力学、电学和压电性质,重点研究了施加应变后原子坐标弛豫与否的Clamped-ion和Relaxed-ion两种模式的弹性刚度系数和压电张量。结果表明单层g-ZnO和g-GaN均具有半导体属性和较好的弹性。单层g-ZnO和g-GaN的压电系数分别约为9.4和2.2 pm·V^(–1),预测这类单层材料在极薄器件中可能具有压电效应,且g-ZnO的压电性能更好。因此,类石墨烯单层ZnO有望用于压力传感器、制动器、换能器及能量收集器等纳米尺度器件。

By employing density functional theory calculations,the mechanical,electronic and piezoelectric properties of graphene-like monolayers ZnO(g-ZnO)and GaN(g-GaN)were investigated.Elastic stiffness constants and piezoelectric tensors of monolayers g-ZnO and g-GaN using their Clamped-ion and Relaxed-ion components were mainly studied.Results indicate that these two graphene-like structures are semiconductors with excellent elasticity.The piezoelectric coefficient of monolayers g-ZnO and g-GaN are about 9.4 and 2.2 pm·V^(–1),respectively,implying their piezoelectric effect in extremely thin film devices,especially the g-ZnO.The remarkable piezoelectricity of monolayer g-ZnO enables it a wide range of applications,such as mechanical stress sensors,actuators,transducer and energy harvesting devices.