单轴应变对Sb_(2)Se_(3)空穴迁移率的影响  

Effect of uniaxial strain on Hole mobility of Sb2Se3

作　　者：张冷 沈宇皓 汤朝阳 吴孔平 张鹏展 刘飞 侯纪伟 Zhang Leng;Shen Yu-Hao;Tang Chao-Yang;Wu Kong-Ping;Zhang Peng-Zhan;Liu Fei;Hou Ji-Wei(School of Electronics and Information Engineering,Jinling Institute of Technology,Nanjing 211169,China;National Laboratory of Solid State Microstructures,School of Physics,Nanjing University,Nanjing 210093,China;Department of Physics,School of Physical and Mathematical Sciences,Nanjing Tech University,Nanjing 211816,China)

机构地区：[1]金陵科技学院电子信息工程学院,南京211169 [2]南京大学物理学院,固体微结构国家实验室,南京210093 [3]南京工业大学数理科学学院,南京211816

出　　处：《物理学报》2024年第11期280-287,共8页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:61904071,52002170);江苏省研究生科技与实践创新计划(批准号:KYCX23_1429);江苏省高校青蓝工程资助的课题。

摘　　要：硒化锑(Sb_(2)Se_(3))是一种物相简单、元素丰富、经济友好的太阳电池吸收层材料,具有广阔的应用前景.然而,Sb_(2)Se_(3)较弱的导电性成为了限制电池器件性能的重要因素.迁移率是材料与器件的重要电学参数,应变可以改变载流子迁移率,因此,研究应变对Sb_(2)Se_(3)的载流子迁移率特性影响具有实际意义.本文通过密度泛函理论和形变势理论,系统研究了单轴应变对Sb_(2)Se_(3)能带结构、禁带宽度、等能面、有效质量的影响,分析了沿着x,y,z方向的三种单轴应变对载流子沿着x,y,z方向的迁移率μx,μy,μz的影响.研究发现,对于无应变的Sb_(2)Se_(3),μx远大于μy和μz,实验上应该将x方向作为Sb_(2)Se_(3)的特定生长方向(即内建电场方向).综合应变对带隙、等能面、分态密度及迁移率的影响,本研究认为当应变沿着y轴方向,且压应变为3%的时候,能获得最佳性能的Sb_(2)Se_(3)太阳电池吸收层材料.Antimony selenide(Sb2Se3)is a simple-phase,element-rich,and economically friendly material for solar cell absorption layers,with broad application prospects.However,the weak conductivity of Sb2Se3 has become a significant factor limiting the performance of solar cell devices.Carrier mobility is an important electrical parameter for both materials and devices,and strain can change carrier mobility.Therefore,studying the effect of strain on the carrier mobility of Sb2Se3 is of practical significance.In this work,using density functional theory and deformation potential theory,we systematically investigate the influence of uniaxial strain on the band structure,bandgap width,iso-surface,and effective mass of Sb2Se3.We analyze the effects of three types of uniaxial strains along the x-,y-,and z-direction on the carrier mobilities along the x-,y-,and z-direction,which are denoted byμx,μy,andμz,respectively.It is found that under these strains,the valence band maximum(VBM)position of Sb2Se3 remains unchanged,and the bandgap decreases with the increase of strain along the y-and z-direction,while it increases along the x-direction.The variation in bandgap may be related to the coupling strength between the Sb-5p orbital and Se-4p orbital of the conduction band minimum(CBM).For fully relaxed Sb2Se3,its iso-surface exhibits a distorted cylindrical shape,with low dispersion along the z-axis and high dispersion along the x-and y-axis,whereμx is greater thanμy andμz,suggesting that the x-direction should be considered as the specific growth direction for Sb2Se3 experimentally.When the strain is applied along the x-and z-direction,μx gradually increases with strain increasing,while it decreases when the strain is applied along the y-direction.Taking into account the combined effects of strain on bandgap,iso-surface,density of states,and mobility,this study suggests that the optimal performance of Sb2Se3 solar cell absorber layer material can be realized when the strain is applied along the y-axis,with a compressive strai

关 键 词：Sb_(2)Se_(3) 迁移率 形变势 应变工程 

分 类 号：TM9[电气工程—电力电子与电力传动]