Self-Assembled GaN:Mg Inverted Hexagonal Pyramids Formed Through a Photoelectrochemical Wet-Etching Process

In this research, small self-assembled inverted hexagonal pyramids of GaN:Mg and multi-quantum-well (MQW) structures were formed using photoelectrochemical wet etching. We studied the formation mechanism of the pyramids during the etching process sequentially as lateral etching, bottom-up etching, and anisotropic etching. The (0001) Ga-face and faces were exposed to achieve the lowest possible surface energy. Due to the strain relief in the tips of the inverted nanopyramids with an MQW active region, an emission peak of photoluminescence with a strong blue shift of 252 meV was induced.