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Thermal stability of crystallographic planes of GaN nanocolumns and their overgrowth by metal organic vapor phase epitaxy
Zubialevich, Vitaly Z.; Pampili, Pietro; Parbrook, Peter J.
Thermal annealing of top−down fabricated GaN nanocolumns (NCs) was investigated over a wide range of temperatures for ammonia-rich atmospheres of both nitrogen and hydrogen. It was found that in contrast to the annealing of planar GaN layers, where surface morphology change is governed purely by material decomposition, reshaping of GaN NCs is strongly affected by competition between different crystallographic facets, which in turn depends on ambient atmosphere and temperature. A qualitative mechanism explaining the observed behavior has been proposed. On the basis of the analysis of these annealing results, growth conditions suitable for either predominantly lateral expansion of the NCs turning their sidewalls into six well-defined vertical m-plane facets, or, vice versa, their infilling from the base regions between the NCs were determined. GaN NC arrays of increased filling factors as compared to the as top−down fabricated ones have been demonstrated using these optimized growth conditions.
Keyword(s): Metallorganic vapor phase epitaxy; Ambient atmosphere; Crystallographic facets; Crystallographic plane; Growth conditions; Lateral expansion; Material decomposition; Metal-organic vapor phase epitaxy; Thermal-annealing
Publication Date:
Type: Journal article
Peer-Reviewed: Yes
Language(s): English
Institution: University College Cork
Funder(s): Higher Education Authority; Science Foundation Ireland
Citation(s): Zubialevich, V. Z., Pampili, P. and Parbrook, P. J. (2020) 'Thermal Stability of Crystallographic Planes of GaN Nanocolumns and Their Overgrowth by Metal Organic Vapor Phase Epitaxy', Crystal Growth & Design, 20(6), pp. 3686-3700. doi: 10.1021/acs.cgd.9b01656
Publisher(s): American Chemical Society
File Format(s): application/pdf
First Indexed: 2021-03-10 07:13:18 Last Updated: 2021-03-10 07:13:18