InxGa1-xAs Nanowires on Silicon: One-Dimensional Heterogeneous Epitaxy, Bandgap Engineering, and Photovoltaics
InxGa1-xAs Nanowires on Silicon: One-Dimensional Heterogeneous Epitaxy, Bandgap Engineering, and Photovoltaics
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DOI：
10.1021/nl202676b
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发表时间：
2011-11-01
期刊：
影响因子：
10.8
通讯作者：
Li, Xiuling
中科院分区：
文献类型：
--
作者：
Shin, Jae Cheol;Kim, Kyou Hyun;Li, Xiuling
报道了在无催化剂和掩模的条件下，用金属有机化学气相沉积（MOCVD）方法在硅（Si）衬底上生长了几乎整个组成范围的InxGa 1-xAs（x = 0.2-1）纳米线。外延生长自发地产生均匀的、非锥形的、高纵横比的NW阵列，其密度超过1 × 10（8）/cm（2）。NW直径（类似于30-250 nm）与InxGa 1-xAs和Si之间的晶格失配（类似于4-11%）成反比，并且可以通过MOCVD生长条件进一步调节。值得注意的是，没有位错已被发现在所有组成的InxGa 1-xAs纳米线，即使大量的堆垛层错和孪晶面存在。通过扫描透射电子显微镜（STEM）和光致发光光谱证实，富铟纳米线表现出更多的锌掺杂，富镓纳米线表现出主要的纤锌矿多型体。使用具有类似于2.2%面积覆盖率的p型Si（111）衬底上的n型In0.3Ga0.7As NW阵列制造的太阳能电池分别在0.37 V和12.9 mA/cm（2）的开路电压V-oc和短路电流密度J（sc）下操作。这项工作是第一个系统的报告，直接一维异质外延的三元InxGa 1-xAs纳米线在硅衬底上的组成/带隙范围宽，可用于晶圆级单片异质集成的高性能photopolics。
We report on the one-dimensional (1D) heteroepitaxial growth of InxGa1-xAs (x = 0.2-1) nanowires (NWs) on silicon (Si) substrates over almost the entire composition range using metalorganic chemical vapor deposition (MOCVD) without catalysts or masks. The epitaxial growth takes place spontaneously producing uniform, nontapered, high aspect ratio NW arrays with a density exceeding 1 x 10(8)/cm(2). NW diameter (similar to 30-250 nm) is inversely proportional to the lattice mismatch between InxGa1-xAs and Si (similar to 4-11%), and can be further tuned by MOCVD growth condition. Remarkably, no dislocations have been found in all composition InxGa1-xAs NWs, even though massive stacking faults and twin planes are present. Indium rich NWs show more zinc-blende and Ga-rich NWs exhibit dominantly wurtzite polytype, as confirmed by scanning transmission electron microscopy (STEM) and photoluminescence spectra. Solar cells fabricated using an n-type In0.3Ga0.7As NW array on a p-type Si(111) substrate with a similar to 2.2% area coverage, operates at an open circuit voltage, V-oc, and a short circuit current density, J(sc), of 0.37 V and 12.9 mA/cm(2), respectively. This work represents the first systematic report on direct 1D heteroepitaxy of ternary InxGa1-xAs NWs on silicon substrate in a wide composition/bandgap range that can be used for wafer-scale monolithic heterogeneous integration for high performance photovoltaics.