Two-step fabrication of self-catalyzed Ga-based semiconductor nanowires on Si by molecular-beam epitaxy
Two-step fabrication of self-catalyzed Ga-based semiconductor nanowires on Si by molecular-beam epitaxy
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分子束外延两步法制备硅基自催化镓基半导体纳米线
DOI：
10.1039/c5nr07830j
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发表时间：
2016
期刊：
影响因子：
6.7
通讯作者：
Zhao Jianhua
中科院分区：
文献类型：
--
作者：
Yu Xuezhe;Li Lixia;Wang Hailong;Xiao Jiaxing;Shen Chao;Pan Dong;Zhao Jianhua
对于在Si上外延生长Ga基III-V半导体纳米线(NWS)，与普通的Au催化剂相比，Ga液滴可以提供一种清洁和兼容的解决方案。然而，除了在Ga催化的GaAsNW研究中使用相对较窄的生长温度(Ts)窗口外，Ga液滴在Si上的应用是相当有限的。本文研究了用分子束外延技术在Si(111)衬底上两步生长Ga催化的III-V纳米线。首先，通过优化表面氧化物，在ts=620°C时获得了高成品率的垂直排列的GaAsNW，然后采用两温工艺在较低的Tc值下保存Ga液滴，从而使GaAsNW的Ts延长到500℃。基于这一过程，可以在最大的ts范围内对Ga催化的GaAsNW进行系统的形态和结构研究。然后，在相同的生长方案下，我们首次实现了Ga催化的GaAsGaSb异质结纳米晶。这些GaSb NW是在GaAsNW截面上轴向生长的，是纯闪锌矿单晶。组成测量证实，催化剂颗粒确实主要由Ga组成，GaSb段纯度高，但含有少量As。最后，我们提出了具有可调Sb组分的GaAsSb NW生长。我们的结果为在Si上可控地合成多组分Ga催化的III-V半导体NWS提供了有用的信息。
For the epitaxial growth of Ga-based III–V semiconductor nanowires (NWs) on Si, Ga droplets could provide a clean and compatible solution in contrast to the common Au catalyst. However, the use of Ga droplets is rather limited except for that in Ga-catalyzed GaAs NW studies in a relatively narrow growth temperature (Ts) window around 620 °C on Si. In this paper, we have investigated the two-step growth of Ga-catalyzed III–V NWs on Si (111) substrates by molecular-beam epitaxy. First, by optimizing the surface oxide, vertically aligned GaAs NWs with a high yield are obtained at Ts = 620 °C. Then a two-temperature procedure is adopted to preserve Ga droplets at lower Ts, which leads to an extension of Ts down to 500 °C for GaAs NWs. Based on this procedure, systematic morphological and structural studies for Ga-catalyzed GaAs NWs in the largest Ts range could be presented. Then within the same growth scheme, for the first time, we demonstrate Ga-catalyzed GaAs/GaSb heterostructure NWs. These GaSb NWs are axially grown on the GaAs NW sections and are pure zinc-blende single crystals. Compositional measurements confirm that the catalyst particles indeed mainly consist of Ga and GaSb sections are of high purity but with a minor composition of As. In the end, we present GaAsSb NW growth with a tunable Sb composition. Our results provide useful information for the controllable synthesis of multi-compositional Ga-catalyzed III–V semiconductor NWs on Si for heterogeneous integration.