Composition Homogeneity in InGaAs/GaAs Core鈥揝hell Nanopillars Monolithically Grown on Silicon

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• 作者：Kar Wei Ng ; Wai Son Ko ; Roger Chen ; Fanglu Lu ; Thai-Truong D. Tran ; Kun Li ; Connie J. Chang-Hasnain
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2014
• 出版时间：October 8, 2014
• 年：2014
• 卷：6
• 期：19
• 页码：16706-16711
• 全文大小：332K
• ISSN：1944-8252

文摘

Alloy composition homogeneity plays an important role in the device performance of III鈥揤 heterostructures. In this work, we study the spatial composition uniformity of n-In_0.12Ga_0.88As/i-In_0.2Ga_0.8As/p-GaAs core鈥搒hell nanopillars monolithically grown on silicon. Cross sections extracted along the axial and radial directions are examined with transmission electron microscopy and energy-dispersive X-ray spectroscopy. Interestingly, indium-deficient segments with width 鈭? nm are observed to develop along the radial 鉄?12虆0鉄?directions in the InGaAs layers. We attribute this spontaneous ordering to capillarity effect and difference in group-III adatom diffusion lengths. The slight fluctuation in indium content (鈭?%), however, does not induce any noticeable misfit defects in the pure wurtzite-phased crystal. In contrast, the heterostructure exhibits excellent alloy composition uniformity along the axial [0001] direction. Furthermore, abrupt transitions of gallium and indium are seen at the heterointerfaces. These remarkable properties give rise to extraordinary optical performances. Lasing is achieved in the core鈥搒hell nanopillars upon optical pump despite the observed alloy composition fluctuation in the radial directions. The results here reveal the potential of the InGaAs-based core鈥搒hell heterostructures as efficient optoelectronic devices and high-speed heterojunction transistors directly integrated on silicon.

Keywords:

III鈭扸 nanopillar; laser; nanowire; core鈭抯hell; alloy ordering