Defects in GaN Nanowires

High resolution and cross-sectional transmission electron microscopy (HRTEM, XTEM) were used to characterize common defects in wurtzite GaN nanowires grown via the vapor-liquid-solid (VLS) mechanism. High resolution transmission electron microscopy showed that these nanowires contained numerous (001) stacking defects interspersed with cubic intergrowths. Using cross-sectional transmission electron microscopy, bicrystalline nanowires were discovered with two-fold rotational twin axes along their growth directions, and were concluded to grow along high index directions or vicinal to low index planes. A defect-mediated VLS growth model was used to account for the prevalence of these extended defects. Implications for nanowire growth kinetics and device behavior are discussed. Comments Postprint version. Published in Advanced Functional Materials, Volume 16, Issue 9, June 2006, pages 1197-1202. Publisher URL: http://www3.interscience.wiley.com/cgi-bin/jhome/77003362 This journal article is available at ScholarlyCommons: http://repository.upenn.edu/mse_papers/114 1 Defects in GaN Nanowires** By Douglas Tham, Chang-Yong Nam and John E. Fischer [*] D. Tham, C. Y. Nam, Prof. J. E. Fischer Department of Materials Science and Engineering, University of Pennsylvania, 3231 Walnut Street, Philadelphia, Pennsylvania 19104-6272 E-mail address: [email protected] [**] This research was supported by the US Department of Energy Grant DE-FG0298ER45701. The use of shared facilities supported by Penn’s NSF/MRSEC under Grant DMR02-03378 is gratefully acknowledged.