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Nucleation and propagation mechanisms for catalyst-free growth of GaN nanowires

Published

Author(s)

Kristine A. Bertness, Devin M. Rourke, Alexana Roshko, Lorelle Mansfield, Aric W. Sanders, Todd E. Harvey, Norman A. Sanford

Abstract

Nucleation of GaN nanowires without catalysts in molecular beam epitaxy is shown to be a distinct process from nanowire propagation. Nanowire growth is relatively insensitive to starting conditions once the nanowire morphology is established, and is driven by variations in Ga sticking coefficient with crystallographic plane under high nitrogen flux and substrates temperatures near 820 ?C. Nanowires are therefore consistently c-axis orientation with {1 -1 0 0} sidewalls. In contrast, nucleation depends strongly on the buffer layer, substrate orientation, and atomic nitrogen flux. AlN buffer layers in the range of 10 nm to 120 nm have been examined, and the density of nanowire nucleation increases with buffer layer thickness. Elimination of the AlN buffer layer produces widely varying morphologies, depending on the initial exposure conditions of the bare silicon surface to nitrogen. These differences have been exploited to pattern substrates for position control of nucleation sites.
Proceedings Title
Extended Abstracts for the 7th International Conference on Nitride Semiconductors
Conference Dates
September 16-21, 2007
Conference Location
Las Vegas, NV
Conference Title
7th International Conference on Nitride Semiconductors

Keywords

gallium nitride, molecular beam epitaxy, nanowires

Citation

Bertness, K. , Rourke, D. , Roshko, A. , Mansfield, L. , Sanders, A. , Harvey, T. and Sanford, N. (2007), Nucleation and propagation mechanisms for catalyst-free growth of GaN nanowires, Extended Abstracts for the 7th International Conference on Nitride Semiconductors, Las Vegas, NV (Accessed May 17, 2022)
Created September 16, 2007, Updated February 19, 2017