Self-organized formation and optical study of GaN micropyramids

In this paper, we report the formation of GaN micropyramids via a self-organized process by ammoniating Ga2O3 powders at high temperature. The obtained GaN micropyramids are typically in wurtzite hexagonal structure, exhibiting six-fold symmetrical morphology and single crystalline characteristic. Cathodoluminescence (CL) studies demonstrated that a weak near-band-edge emission centered at ∼385 nm and a broad yellow-band in the range of 500–800 nm were observed in the GaN micropyramids, and the related light emission mechanism was discussed based on the microstructure analysis.

► GaN micropyramids could be synthesized through a feasible self-organized CVD process.
► HRTEM analysis indicated that the GaN pyramids are of high crystal quality without structural defects.
► Cathodoluminescence measurement shows that the GaN pyramids possess a near band-edge emission at 385 nm and a broad yellow band in visible range.