Solid State Physics Laboratory, Lucknow Road, Timarpur, Delhi 110 054, India.
Nanotechnology. 2012 Jan 20;23(2):025601. doi: 10.1088/0957-4484/23/2/025601. Epub 2011 Dec 14.
We report the self-catalyzed growth of GaAs nanowire arrays by metalorganic vapor phase epitaxy (MOVPE) on GaAs vicinal substrates. The effect of substrate misorientation on the nanowire growth and the influence of growth parameters such as temperature and input V/III ratio have been studied in detail. Variation in the nanowire growth mechanism and consequential changes in the nanowire growth morphology were observed. A VLS growth mechanism with negligible effect of the vicinal surface gave rise to randomly distributed droplet-terminated GaAs nanowires at 400 °C and multiprong root-grown GaAs nanowire clusters at 500 °C with low V/III ratio. The substrate misorientation effect was dominant at 500 °C with higher V/III ratio, in which case the combined effect of the vicinal surface and the self-catalyzed Ga droplets assisted the realization of self-assembled and crystallographically oriented epitaxial nanowire arrays through the vapor-solid mechanism.
我们通过金属有机气相外延（MOVPE）在砷化镓晶面外延衬底上报告了 GaAs 纳米线阵列的自催化生长。详细研究了衬底偏离度对纳米线生长的影响以及温度和输入 V/III 比等生长参数的影响。观察到纳米线生长机制的变化以及由此引起的纳米线生长形态的变化。在 400°C 时，采用 VLS 生长机制且晶面偏离度的影响可忽略不计，导致随机分布的液滴终止 GaAs 纳米线；在 500°C 时，采用低 V/III 比的多叉根生长 GaAs 纳米线簇，采用 VLS 生长机制，晶面偏离度的影响占主导地位。在 500°C 时，V/III 比较高，晶面偏离度的影响占主导地位，在这种情况下，晶面和自催化 Ga 液滴的共同作用通过汽-固机制辅助实现了自组装和晶向外延纳米线阵列。
