Identification of an Intrinsic Source of Doping Inhomogeneity in Vapor鈥揕iquid鈥揝olid-Grown Nanowires

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• 作者：Justin G. Connell ; KunHo Yoon ; Daniel E. Perea ; Edwin J. Schwalbach ; Peter W. Voorhees ; Lincoln J. Lauhon
• 刊名：Nano Letters
• 出版年：2013
• 出版时间：January 9, 2013
• 年：2013
• 卷：13
• 期：1
• 页码：199-206
• 全文大小：487K
• 年卷期：v.13,no.1(January 9, 2013)
• ISSN：1530-6992

文摘

The vapor鈥搇iquid鈥搒olid (VLS) process of semiconductor nanowire growth is an attractive approach to low-dimensional materials and heterostructures because it provides a mechanism to modulate, in situ, nanowire composition and doping, but the ultimate limits on doping control are ultimately dictated by the growth process itself. Under widely used conditions for the chemical vapor deposition growth of Si and Ge nanowires from a Au catalyst droplet, we find that dopants incorporated from the liquid are not uniformly distributed. Specifically, atom probe tomographic analysis revealed up to 100-fold enhancements in dopant concentration near the VLS trijunction in both B-doped Si and P-doped Ge nanowires. We hypothesize that radial and azimuthal inhomogeneities arise from a faceted liquid鈥搒olid interface present during nanowire growth, and we present a simple model to account for the distribution. As the same segregation behavior was observed in two distinct semiconductors with different dopants, the observed inhomogeneity is likely to be present in other VLS grown nanowires.

Keywords:

Nanowire; semiconductor; doping; atom probe tomography; synthesis