Optimization of Si doping in GaN nanowires for high-performance photoelectrochemical photodetectors

Photoelectrochemical-type photodetectors (PEC PDs) have received extensive attention owing to their low cost, simple fabrication process, and high photoresponse adjustability. Here, we fabricated GaN nanowires with different Si-doping concentrations by changing the temperature of the silicon cell in plasma-assisted molecular beam epitaxy.  The influence of Si-doping concentration on the PEC PD performance of GaN-based nanowire photoelectrodes was studied. The experimental results show that the photoresponse performance of the PEC PD can be significantly improved by adjusting the Si-doping concentration of GaN nanowire. When T_si = 1120°C, the doped GaN nanowires photoelectrode exhibited the maximum photoresponse, which was 20 times greater than that of undoped GaN nanowire photoelectrode.