ZnO/GaN核/壳异质结纳米线能带结构和电荷分离的理论研究  

Theoretical Study on Energy Band Structure and Charge Separation of GaN-ZnO Core/Shell Heterojunction Nanowires Structure

作　　者：陈星源[1] 罗文杰[1] 赖国霞[1] 古迪[1] 朱伟玲[1] 徐祥福[1] 

机构地区：[1]广东石油化工学院应用物理系,茂名525000

出　　处：《人工晶体学报》2018年第2期308-314,共7页Journal of Synthetic Crystals

基　　金：国家自然科学基金(11547201;61475195);广东省自然科学基金(2015A030313873);广东省教育厅基金(2015KQNCX098;2015KQNCX100;2016KTSCX087)

摘　　要：采用密度泛函第一性原理的方法计算了GaN纳米线、ZnO纳米线及其核/壳纳米线结构的能带结构,价带顶(VBM)和导带底(CBM)的电荷分布。计算表明本征GaN和ZnO纳米线材料VBM和CBM所对应电荷分布较为分散,且与直径关系不大,形成不了Ⅱ型半导体电荷分离效应。GaN和ZnO组成的核/壳纳米线均保持本征GaN和ZnO纳米线的直接带隙性质。在ZnO包裹GaN的核壳纳米线结构中,不同比例的ZnO和GaN之间电荷转移均不明显,VBM和CBM电荷分布基本都是由壳层的ZnO的O原子占据,难于实现VBM和CBM电荷空间分离。在GaN包裹ZnO的核壳纳米线结构中,VBM电荷和CBM电荷分布分别主要由壳层的N原子占据和核层的O原子占据,同时ZnO和GaN之间的电荷转移量相对较大,容易形成较大的核壳内置电场,有利于促进空间电荷分离,并且随着ZnO的比例增加电荷转移量也相应增加,能有效的促进电荷分离有利于制备成Ⅱ型半导体。The energy band structure, charge distribution of the Valence Band Maximum （VBM） and Conduction Band Minimum （CBM） of GaN nanowires, ZnO nanowires and its core/shell nanowire structures were calculated by density functional theory. The calculated results indicate that the VBM and CBM charge distribution in GaN and ZnO nanowire with different diameter are relatively dispersed, which could not form the charge separation effect of type II semiconductor. The properties of direct band gap are maintained in the GaN-ZnO core/shell nanowires. The charge transfer between different proportions of ZnO and GaN are not obvious in the GaN/ZnO core/shell nanowires structure. The charge space separation of the VBM and CBM charge distribution are difficult to be achieved since they are mainly occupied by the O atom of ZnO outer shell. The VBM and CBM charge distribution are occupied by the N atoms outer shell and O atoms inner core respectively in the ZnO/GaN core/shell nanowires structure. The charge transfer between ZnO and GaN are obvious and become larger with the increased proportion of ZnO in the ZnO/GaN core/shell nanowires structure, which could lead to a larger core/shell electric field and promote the charge separation to aehieve type II semiconductor.

关 键 词：第一性原理 GaN/ZnO核/壳结构纳米线 能带结构 电荷分离 

分 类 号：O562.1[理学—原子与分子物理]