电场调控范德华异质薄膜能隙的第一性原理研究:单层SiC沉积在表面氢化的BN薄膜上  

First-principles of Tunable Band Gaps of van der Waals Heterostructures Under Electric Field:Monolayer SiC on Hydrogenated BN Nanosheets

作　　者：肖美霞[1] 冷浩 姚婷珍[1] 王磊[1] 何成[2] XIAO Meixia;LENG Hao;YAO Tingzhen;WANG Lei;HE Cheng(School of Materials Science and Engineering,Xi’an Shiyou University,Xi’an 710065,China;State Key Laboratory for Mechanical Behavior of Materials,Xi’an Jiaotong University,Xi’an 710049,China)

机构地区：[1]西安石油大学材料科学与工程学院,西安710065 [2]西安交通大学金属材料强度国家重点实验室,西安710049

出　　处：《材料导报》2022年第8期60-65,共6页Materials Reports

基　　金：国家自然科学基金青年基金(51801155);西安石油大学《材料科学与工程》省级优势学科(ys37020203)。

摘　　要：碳化硅(SiC)作为第三代半导体材料的典型代表,是目前应用最理想的宽禁带半导体材料之一,在半导体照明、电子设备等领域具有广阔的应用前景。本工作通过基于密度泛函理论并考虑原子间范德华力相互作用的第一性原理,系统地研究了SiC沉积在表面完全氢化的BN衬底上形成的SiC/HBNH异质薄膜的原子结构和电学性质,并探索电场对其能隙的调控效果。研究结果表明,Si和C原子相对HBNH薄膜的位置将决定其结构稳定性及异质薄膜间相互作用的强弱程度,因此堆垛类型可有效调节SiC/HBNH异质薄膜的能隙,并且异质薄膜的导带底和价带顶分别由SiC、HBNH纳米薄膜来决定,可实现电子和空穴输运轨道的分离。当施加外电场时,SiC/HBNH异质薄膜能隙伴随电场强度的增加呈现出近似线性下降分布,会由直接能隙转变为间接能隙,甚至转变为导体,这主要是由电场增强异质薄膜间的相互作用引起的。该研究结果证实了堆垛类型和电场可有效调节SiC/HBNH异质薄膜的电学性质,降低电子和空穴的结合概率,为其应用于新型电子纳米器件提供重要的理论指导。As a typical representative of the third generation semiconductor materials,silicon carbide(SiC)is one of the most ideally wide band gap semiconductor materials,which has a wide application prospect in semiconductor lighting device and electronic equipment.In this work,we have systematically investigated structural and electronic properties of monolayer SiC on fully-hydrogenated BN nanosheets(SiC/HBNH)and studied the effects of electric field on the band gaps of SiC/HBNH heterobilayers using first-principles calculations based on the density functional theory with van der Waals corrections.The results show that the position of Si and C atoms relative to HBNH nanosheet can determine the structural stability and the interaction strength between SiC and HBNH nanosheets.Therefore,the stacking types can effectively regulate the energy gaps of SiC/HBNH heterobilayers.Moreover,the conduction band minimum and valence band maximum of the heterobilayers are determined by SiC and HBNH nanosheets,respectively,leading to the separation of electrons and holes.Applying an electric field,a linear distribution of band gaps is a function of the strength of electric field,accompanied with a transition from direct semiconductors to indirect semiconductors even to conductors,which are primarily induced the stronger interaction between SiC and HBNH nanosheets.The results demonstrate that the stacking arrangements and electric field can effectively tune the electronic properties of SiC/HBNH heterobilayers,and reduce the recombination probability of electrons and holes,which open a way for the diverse and tunable electronic properties of semiconductor heterostructures in novel electronic nanodevices.

关 键 词：碳化硅异质薄膜 第一性原理 范德华力相互作用 电场 电学性质 

分 类 号：O472[理学—半导体物理] O738[理学—物理]