Selective lateral photoelectrochemical wet etching of InGaN nanorods

Abstract

Vertically aligned InGaN nanorods (NRs) sandwiched between GaN layers on sapphire substrates were synthesized by photoelectrochemical (PEC) wet etching. The InxGaN/InyGaN superlattice layer was laterally etched into NRs by selectively removing the material between dislocations due to the nonradiative recombination occurring at the dislocations. The mechanism of this PEC etching is examined in detail by characterizing it with different InGaN doping concentrations, KOH concentrations, and etching times. A lateral etch rate of 80 nm/min was achieved for an n-type doping concentration of 1.1 × 1019 cm−3 and a KOH concentration of 2.2M. This demonstration provides a simple but promising method for GaN nanostructure fabrication, which suggests further potential applications for GaN-based optical devices.