Features of the selective growth of GaN nanorods on patterned $c$-sapphire substrates of various configurations

The growth features of GaN nanorods on patterned c -sapphire substrates with a regular microcone array having a different density and base diameter in the ranges of (1–5) $\cdot$ 10$^{7}$ cm $^{-2}$ and 2.5–3.5 $\mu$m, respectively, are investigated. The kinetics is studied and the selective-growth regimes are determined for single GaN nanorods with a diameter of 30–100 nm at the vertices of microcones under radically lower growth rates on their slopes. The effect of the configuration of microcones, the substrate temperature, the roughness of the initial surface, and the presence of indium as a surfactant on the degree of growth selectivity is investigated.