ZnSe/Si 核壳纳米线异质结构的可调带隙和导电类型

Tunable Band Gap and Conductivity Type of ZnSe/Si Core-Shell Nanowire Heterostructures.

作者信息

Zeng Yijie, Xing Huaizhong, Fang Yanbian, Huang Yan, Lu Aijiang, Chen Xiaoshuang

机构信息

Department of Applied Physics and State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, Donghua University, Ren Min Road 2999, Songjiang District, Shanghai 201620, China.

National Lab of Infrared Physics, Shanghai Institute for Technical Physics, Chinese Academy of Science, 500 Yu Tian Road, Shanghai 200083, China.

出版信息

Materials (Basel). 2014 Oct 31;7(11):7276-7288. doi: 10.3390/ma7117276.

DOI:10.3390/ma7117276

PMID:28788245

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC5512634/

Abstract

The electronic properties of zincblende ZnSe/Si core-shell nanowires (NWs) with a diameter of 1.1-2.8 nm are calculated by means of the first principle calculation. Band gaps of both ZnSe-core/Si-shell and Si-core/ZnSe-shell NWs are much smaller than those of pure ZnSe or Si NWs. Band alignment analysis reveals that the small band gaps of ZnSe/Si core-shell NWs are caused by the interface state. Fixing the ZnSe core size and enlarging the Si shell would turn the NWs from intrinsic to -type, then to metallic. However, Fixing the Si core and enlarging the ZnSe shell would not change the band gap significantly. The partial charge distribution diagram shows that the conduction band maximum (CBM) is confined in Si, while the valence band maximum (VBM) is mainly distributed around the interface. Our findings also show that the band gap and conductivity type of ZnSe/Si core-shell NWs can be tuned by the concentration and diameter of the core-shell material, respectively.

摘要

通过第一性原理计算方法，计算了直径为1.1 - 2.8纳米的闪锌矿结构ZnSe/Si核壳纳米线（NWs）的电子性质。ZnSe核/Si壳和Si核/ZnSe壳纳米线的带隙均远小于纯ZnSe或Si纳米线的带隙。能带对齐分析表明，ZnSe/Si核壳纳米线的小带隙是由界面态引起的。固定ZnSe核尺寸并增大Si壳会使纳米线从本征型转变为n型，进而转变为金属型。然而，固定Si核并增大ZnSe壳不会显著改变带隙。部分电荷分布图表明，导带最大值（CBM）局限于Si中，而价带最大值（VBM）主要分布在界面周围。我们的研究结果还表明，ZnSe/Si核壳纳米线的带隙和导电类型可分别通过核壳材料的浓度和直径进行调节。