Realization of vertically-aligned GaN n-p core-shell nanoscale structures using top-down fabrication

In this contribution, we report on development of a hybrid approach to produce arrays of vertically aligned GaN n-p core-shell structures. First, we fabricated nanoscale n-type GaN pillars by inductively coupled plasma (ICP) etching which were subsequently overgrown by p-type GaN shell using halide vapor phase epitaxy (HVPE) process. We will present results on the optimization of the ICP etching procedure, in particular ICP and radio frequency (RF) powers, to obtain GaN pillars with vertical and smooth sidewalls. Preliminary results on HVPE overgrowth and characterization of core-shell GaN pillars will be discussed as well.