Near-surface depletion of antimony during the growth of GaAsSb and GaAs/GaAsSb nanowires
Near-surface depletion of antimony during the growth of GaAsSb and GaAs/GaAsSb nanowires
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DOI：
10.1063/1.4896904
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发表时间：
2014-10
影响因子：
3.2
通讯作者：
H. Kauko;B. Fimland;T. Grieb;A. M. Munshi;K. Müller;A. Rosenauer;A. V. Helvoort
中科院分区：
文献类型：
--
作者：
H. Kauko;B. Fimland;T. Grieb;A. M. Munshi;K. Müller;A. Rosenauer;A. V. Helvoort
用定量大角度环形暗场扫描电子显微镜(STEM)研究了GaAsSb纳米线(NWS)和插入GaAsSb的GaAsSb纳米线生长过程中Sb摩尔分数的近表面还原。建立了Sb在六角形原子核中的扩散模型，并与STEM定量分析相结合。研究了用Ga辅助分子束外延(MBE)方法生长的GaAsSb纳米晶和用Ga和Au辅助分子束外延生长的GaAsSb纳米晶。在NW生长所采用的高温下，As-Sb交换发生，Sb向表面向外扩散，导致GaAsSb NW和GaAsSb插件中Sb在表面及其附近的浓度降低。在GaAsSb NWS中，由于较长时间暴露在As束流中，在NW底部观察到Sb的近表面耗尽增加。在GaAsSb衬底中，随着插入后轴向生长的GaAsSb衬底厚度的增加，Sb浓度分布的变化越来越大.
The near-surface reduction of the Sb mole fraction during the growth of GaAsSb nanowires (NWs) and GaAs NWs with GaAsSb inserts has been studied using quantitative high-angle annular dark field scanning transmission electron microscopy (STEM). A model for diffusion of Sb in the hexagonal NWs was developed and employed in combination with the quantitative STEM analysis. GaAsSb NWs grown by Ga-assisted molecular beam epitaxy (MBE) and GaAs/GaAsSb NWs grown by Ga- and Au-assisted MBE were investigated. At the high temperatures employed in the NW growth, As-Sb exchange at and outward diffusion of Sb towards the surface take place, resulting in reduction of the Sb concentration at and near the surface in the GaAsSb NWs and the GaAsSb inserts. In GaAsSb NWs, an increasing near-surface depletion of Sb was observed towards the bottom of the NW due to longer exposure to the As beam flux. In GaAsSb inserts, an increasing change in the Sb concentration profile was observed with increasing post-insert axial GaAs grow...