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Understanding the role of facets and twin defects in the optical performance of GaAs nanowires for laser applications
Nanoscale Horizons ( IF 9.7 ) Pub Date : 2021-5-6 , DOI: 10.1039/d1nh00079a
Zahra Azimi 1 , Nikita Gagrani , Jiangtao Qu , Olivier L C Lem , Sudha Mokkapati , Julie M Cairney , Rongkun Zheng , Hark Hoe Tan , Chennupati Jagadish , Jennifer Wong-Leung
Affiliation  

GaAs nanowires are regarded as promising building blocks of future optoelectronic devices. Despite progress, the growth of high optical quality GaAs nanowires is a standing challenge. Understanding the role of twin defects and nanowire facets on the optical emission and minority carrier lifetime of GaAs nanowires is key for the engineering of their optoelectronic properties. Here, we present new insights into the microstructural parameters controlling the optical properties of GaAs nanowires, grown via selective-area metal–organic vapor-phase epitaxy. We observe that these GaAs nanowires have a twinned zinc blende crystal structure with taper-free {110} side facets that result in an ultra-low surface recombination velocity of 3.5 × 104 cm s−1. This is an order of magnitude lower than that reported for defect-free GaAs nanowires grown by the vapor–liquid–solid technique. Using time-resolved photoluminescence and cathodoluminescence measurements, we untangle the local correlation between structural and optical properties demonstrating the superior role of the side facets in determining recombination rates over that played by twin defects. The low surface recombination velocity of these taper-free {110} side facets enable us to demonstrate, for the first time, low-temperature lasing from bare (unpassivated) GaAs nanowires, and also efficient room-temperature lasing after passivation with an AlGaAs shell.

中文翻译:

了解刻面和孪晶缺陷在激光应用GaAs纳米线的光学性能中的作用

GaAs纳米线被认为是未来光电器件的有前途的构建基块。尽管取得了进步,但高光学质量的GaAs纳米线的增长仍然是一个挑战。理解孪晶缺陷和纳米线刻面对GaAs纳米线的光发射和少数载流子寿命的作用是设计其光电性能的关键。在这里,我们提出了新的见解的微观结构参数控制的GaAs纳米线,生长的光学性质通过选择性面积的金属-有机汽相外延。我们观察到,这些GaAs纳米线具有孪晶锌共混物晶体结构,具有无锥度的{110}侧面,导致3.5×10 4 cm s -1的超低表面复合速度。这比通过气-液-固技术生长的无缺陷GaAs纳米线所报告的数量级要低一个数量级。使用时间分辨的光致发光和阴极发光测量,我们解开了结构和光学性质之间的局部相关性,证明了侧面在确定重组率方面比双缺陷所具有的优越性。这些无锥度的{110}侧面的低表面重组速度使我们首次展示了从裸露的(未钝化的)GaAs纳米线发出的低温激光,以及在用AlGaAs壳进行钝化后的有效室温激光发射。 。
更新日期:2021-05-18
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