Self assembled Gallium droplets are used as catalyst for epitaxial growth of III-V semiconductor nanowires. Understanding the effect of droplets’ nanostructure on in situ catalysed growth of nanowires is essential. Evolution of MOCVD grown Ga droplets’ self-assembled structure under different growth conditions, therefore, has been studied. The droplet nanomorphology has been explained on the basis of Ostwald-ripening based coalescence growth model. Two major morphologies of Ga droplets have been observed, namely, Valved and Spherical. Where a partial coalescence leads to the formation of valved nanostructures, complete coalescence of droplets give rise to spherical nanomorphology. Droplet morphology has been observed to have significant effect on in situ catalysed growth of GaAs nanowires by MOCVD. Twin and singular nanowires have been grown using valved and spherical Ga droplets, respectively, as catalyst. In addition, Gallium droplets having spherical nanomorphology with average diameter of around 80 nm and surface density of about 4×10⁹ /cm² have been subjected to ex situ chemical oxidation to examine their chemical and morphological stability. The scanning electron microscopy of the oxidised sample has confirmed the retention of spherical morphology. The detailed theoretical depth analysis of the photoemission spectrum of the oxidised droplets has revealed the formation of interesting Ga-Ga₂O₃ core-shell nanostructure within a spherical droplet with a shell thickness of more than 3 nm.

中文翻译：

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通过金属有机化学气相沉积生长的自组装镓液滴的原位和非原位结合纳米形态

自组装的镓液滴用作III-V半导体纳米线的外延生长的催化剂。了解液滴的纳米结构对原位催化纳米线生长的影响至关重要。因此，研究了在不同生长条件下MOCVD生长的Ga液滴自组装结构的演化。液滴的纳米形态已经在基于Ostwald-ripning的聚结生长模型的基础上进行了解释。已经观察到Ga液滴的两种主要形态，即阀形和球形。当部分聚结导致形成带阀的纳米结构时，液滴的完全聚结会产生球形的纳米形态。观察到液滴形态对原位有显着影响MOCVD催化GaAs纳米线的生长。分别使用带阀的和球形的Ga液滴作为催化剂来生长双纳米线和奇异纳米线。另外，镓液滴具有波长约80的平均直径以及大约4×10表面密度球形nanomorphology ⁹ /厘米²已经经受至E X原位化学氧化来检查它们的化学和形态稳定性。氧化样品的扫描电子显微镜已证实保留了球形形态。对氧化液滴的光发射光谱进行详细的理论深度分析，揭示了有趣的Ga-Ga ₂ O _3的形成 球形液滴内的核-壳纳米结构，壳厚度大于3 nm。