2008 NSTI Nanotechnology Conference and Trade Show - Nanotech 2008 - 11th Annual

Partnering Events:

TechConnect Summit
Clean Technology 2008

Advances in Understanding III-V Nanowire Growth

S.A. Dayeh, E.T. Yu, D. Wang
University of California, San Diego, US

Keywords:
nanowire, InAs, growth

Abstract:
We present systematic studies on temperature, V/III ratio, and time dependence of Au-assisted III-V NW growth using MOCVD. The temperature windows for InAs NWs grow are dependent on the effective V/III ratio at the growth interface that increases with increasing temperature. Higher V/III ratios favor vapor-solid or thin-film growth over the VLS growth and hinder group-III diffusion to the growth seed causing cessation of the VLS NW growth. New fundamental insights into the NW nucleation and evolution were obtained from time-dependent growth performed at two input group-III flow rates. At low group-III flow, no substrate-to-NW diffusion occurs and the NW growth proceeds at an exponential rate for NW lengths (LNW) less than the group-III diffusion length on the NW surface ( NW) followed by an asymptotic-linear growth rate when LNW > NW. On the other hand, large group-III flow allows longer surface diffusion lengths on the substrate and substrate-to-NW diffusion prevails allowing earlier NW nucleation and an increased growth rate that proceeds logarithmic for LNW > NW and asymptotic for LNW < NW These studies not only enhance our understanding of the governing mechanism but also provide clear guidance and necessary parameters for optimal control over NW morphology and properties.


Nanotech 2008 Conference Program Abstract