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Faceting Control in Core/Shell GaN micropillars using Selective Epitaxy



Sergiy Krylyuk, Heayoung Yoon, Baomei Wen, Abhishek Motayed, Albert Davydov, Matt N. King


We report on fabricating large-area, vertically aligned GaN epitaxial core-shell micropillar arrays. The two-step process consisted of inductively coupled plasma (ICP) etch of lithographically patterned n-type GaN substrate followed by selective growth of undoped shells using Halide Vapor Phase Epitaxy (HVPE). The most significant aspect of the study is control of sidewall faceting in the shells, ranging from {1 01} semi-polar to {1 00} non-polar planes, by employing a post-ICP chemical etch and by tuning HVPE growth temperature. X-ray diffraction indicated improvement in the crystal quality after the shell formation. Room-temperature photoluminescence and Raman scattering measurements revealed substantial reduction in parasitic yellow luminescence as well as strain- relaxation in the overgrown core-shell structures. High-resolution cathodoluminescence spectroscopy and imaging further elucidated the radiative/non-radiative recombination centers in individual core- shell structures. This study demonstrates the feasibility of selective epitaxy on micro/nano- engineered templates for
APL Materials


Nitride, Micropillars, Core-shell, non-polar, HVPE, Top-down, Photoluminescence


Krylyuk, S. , Yoon, H. , Wen, B. , Motayed, A. , Davydov, A. and King, M. (2014), Faceting Control in Core/Shell GaN micropillars using Selective Epitaxy, APL Materials (Accessed June 20, 2024)


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Created October 15, 2014, Updated March 15, 2017