Department of Electrical Engineering and Computer Sciences, University of California at Berkeley , Berkeley, California 94720, United States.
Nano Lett. 2014 Jan 8;14(1):183-90. doi: 10.1021/nl403712f. Epub 2013 Dec 16.
Nanoscale self-assembly offers a pathway to realize heterogeneous integration of III-V materials on silicon. However, for III-V nanowires directly grown on silicon, dislocation-free single-crystal quality could only be attained below certain critical dimensions. We recently reported a new approach that overcomes this size constraint, demonstrating the growth of single-crystal InGaAs/GaAs and InP nanoneedles with the base diameters exceeding 1 μm. Here, we report distinct optical characteristics of InP nanoneedles which are varied from mostly zincblende, zincblende/wurtzite-mixed, to pure wurtzite crystalline phase. We achieved, for the first time, pure single-crystal wurtzite-phase InP nanoneedles grown on silicon with bandgaps of 80 meV larger than that of zincblende-phase InP. Being able to attain excellent material quality while scaling up in size promises outstanding device performance of these nanoneedles. At room temperature, a high internal quantum efficiency of 25% and optically pumped lasing are demonstrated for single nanoneedle as-grown on silicon substrate. Recombination dynamics proves the excellent surface quality of the InP nanoneedles, which paves the way toward achieving multijunction photovoltaic cells, long-wavelength heterostructure lasers, and advanced photonic integrated circuits.
纳米自组装为在硅上实现 III-V 材料的异质集成提供了一条途径。然而，对于直接在硅上生长的 III-V 纳米线，只有在一定的临界尺寸以下才能获得无位错单晶质量。我们最近报道了一种克服这一尺寸限制的新方法，成功生长了基底直径超过 1 微米的单晶 InGaAs/GaAs 和 InP 纳米针。在这里，我们报告了 InP 纳米针的独特光学特性，其晶体相从主要闪锌矿、闪锌矿/纤锌矿混合相到纯纤锌矿相变化。我们首次实现了在硅上生长具有 80meV 带隙的纯单晶纤锌矿相 InP 纳米针，其带隙大于闪锌矿相 InP。在尺寸上能够实现优异的材料质量，有望实现这些纳米针的出色器件性能。在室温下，我们演示了在硅衬底上生长的单个纳米针的 25%的高内量子效率和光泵浦激光。复合动力学证明了 InP 纳米针具有优异的表面质量，为实现多结光伏电池、长波长异质结构激光器和先进的光子集成电路铺平了道路。
