AVS 53rd International Symposium
    Nanometer-scale Science and Technology Friday Sessions
       Session NS-FrM

Paper NS-FrM6
Synthesis and Characterization of Aligned III-Nitride Nanowire and Heterostructure Nanowire Arrays

Friday, November 17, 2006, 9:40 am, Room 2016

Session: Nanowires
Presenter: G.T. Wang, Sandia National Laboratories
Authors: G.T. Wang, Sandia National Laboratories
A.A. Talin, Sandia National Laboratories
J.R. Creighton, Sandia National Laboratories
D. Werder, Los Alamos National Laboratory
E. Lai, Sandia National Laboratories
P.P. Provencio, Sandia National Laboratories
Correspondent: Click to Email
Nanowires based on the direct bandgap semiconductor Group III nitride (AlGaInN) materials system have attracted attention as potential building blocks in nanophotonics, nanoelectronics, and sensing. We have employed a metal-organic chemical vapor deposition process to synthesize highly aligned arrays of single-crystalline GaN nanowires in a standard cold-wall rotating disk reactor on 2-inch diameter sapphire and GaN substrates without the use of a template. SEM and TEM analysis indicate that the nanowires share a common growth direction and have aligned facets. Interestingly, the majority of the nanowires do not have a catalyst droplet at the tip, suggesting the growth may differ from the standard vapor-liquid-solid process. Building on this technique, we have also been able to synthesize radial heterostructure nanowire arrays consisting of a GaN cores and various III-nitride shell materials, including AlN, InN, and AlGaN, and InGaN. The GaN and heterostructure nanowires were probed using a Sandia-developed platform which allows us to correlate the morphological, optical, and electrical properties of a statistically relevant number of nanowires. Results from 3D STEM tomography and spatially resolved photoluminescence and cathodoluminescence studies will also be presented. We have found that the growth conditions, particularly temperature, have a strong effect on the structural, optoelectronic, and electrical properties of the nanowires. Additionally, the choice of substrate and the catalyst preparation play critical roles in the density, uniformity, and alignment of the nanowire arrays. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy under contract DE-AC04-94AL85000.