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The use of etched nanorods from a planar template as a growth scaffold for a highly regular GaN/InGaN/GaN core-shell structure is demonstrated. The recovery of m-plane non-polar facets from etched high-aspect-ratio GaN nanorods is studied with and without the introduction of a hydrogen silsesquioxane passivation layer at the bottom of the etched nanorod arrays. This layer successfully prevented c-plane growth between the nanorods, resulting in vertical nanorod sidewalls (∼89.8°) and a more regular height distribution than re-growth on unpassivated nanorods. The height variation on passivated nanorods is solely determined by the uniformity of nanorod diameter, which degrades with increased growth duration. Facet-dependent indium incorporation of GaN/InGaN/GaN core-shell layers regrown onto the etched nanorods is observed by high-resolution cathodoluminescence imaging. Sharp features corresponding to diffracted wave-guide modes in angle-resolved photoluminescence measurements are evidence of the uniformity of the full core-shell structure grown on ordered etched nanorods.
Le Boulbar, E. D., Girgel, I., Lewins, C. J., Edwards, P. R., Martin, R. W., Šatka, A., Allsopp, D. W. E., & Shields, P. A. (2013). Facet recovery and light emission from GaN/InGaN/GaN core-shell structures grown by metal organic vapour phase epitaxy on etched GaN nanorod arrays. Journal of Applied Physics, 114(9), . https://doi.org/10.1063/1.4819440