Zn-Doped p-Type Gallium Phosphide Nanowire Photocathodes from a Surfactant-Free Solution Synthesis

Gallium phosphide (GaP) nanowire photocathodes synthesized using a surfactant-free solution-liquid-solid (SLS) method were investigated for their photoelectrochemical evolution of hydrogen. Zinc as a p-type dopant was introduced into the nanowires during synthesis to optimize the photocathode's response. Investigation of the electrical properties of Zn-doped GaP nanowires confirmed their p-type conductivity. After optimization of the nanowire diameter and Zn doping concentration, higher absorbed photon-to-current efficiency (APCE) over the spectrum was achieved. The versatility of the SLS synthesis and the capability to control the electrical properties suggest that our approach could be generalized to other III-V and II-VI semiconductors.