Axial p–n Junctions in GaN Microrods

Abstract

GaN microrods with an axial p–n junction are grown by metal‐organic vapor phase epitaxy (MOVPE). Scanning electron microscopy in combination with cathodoluminescence measurements have been performed to visualize the microrod sections consisting of n‐ and p‐type GaN and the p–n junction. Current–voltage measurements are carried out between different microrod sections to prove the successful formation of a p–n junction. Photovoltaic and photodetecting properties have been determined by illumination of the p–n junction with a UV laser. The shorter p‐type sections in axial microrods and the presence of large diameter rods suggest a growth mode change from vertical to lateral growth during p‐type deposition.