Electrical and optical characterization of GaN micro-wires

A near atmospheric pressure solution growth process was developed to produce an abundant quantity of GaN micro-wires in the c-direction with a length of tens of microns and a diameter of approximately 1–10 μm. Raman analysis showed that the micro-wires were free of stress which was expected for a free-forming crystal. The lack of stress and extended defects in the GaN micro-wire provided a useful test-bed to directly compare the wet-etch behavior of the polar c-planes and non-polar m-planes in GaN. The etch behavior at the end of the micro-wire (±c) was dramatically different, with the (0 0 0 1) plane found to be stable and the (0 0 0 −1) plane observed to rapidly etch into nanoscale hexagonal pyramids. Additionally a dielectrophoretic method was employed to readily align the wires as part of a larger device processing sequence.