High responsivity GaN nanowire UVA photodetector synthesized by hydride vapor phase epitaxy

Abstract

A gallium nitride (GaN) nanowire (NW) UVA photodetector with high responsivity was reported. The GaN NW was grown by horizontal hydride vapor phase epitaxy. The NW morphology is proved tunable via different growth conditions. The axial and radial growths of GaN NWs were investigated through vapor-liquid-solid and vapor-solid mixed growth models. Besides, NWs with different morphologies exhibit different growth crystal orientations, which depend on the flow rate of HCl. NWs with smaller diameters show better optical properties and crystalline quality. More importantly, the UVA detector fabricated by a single NW exhibits excellent responsivity of 4.35 × 104-1.06 × 105 A/W and external quantum efficiency of 1.48 × 107%-3.6 × 107% under different light power densities. The high responsivity and low production cost make the GaN NW UVA detector extremely attractive for several applications, such as fire sensing and missile and rocket warning.