Enhanced photoelectrochemical performance of InGaN-based nanowire photoanodes by optimizing the ionized dopant concentration

InGaN-based nanowires (NWs) have been extensively studied for photoelectrochemical (PEC) water splitting devices owing to their tunable bandgap and good chemical stability. Here, we further investigated the influence of Si doping on the PEC performance of InGaN-based NW photo anodes. The Si dopant concentration was controlled by tuning the Si effusion cell temperature (T-Si) during plasma-assisted molecular beam epitaxy growth and further estimated by Mott-Schottky electrochemical. measurements. The highest Si dopant concentration of 2.1 x 10(18) cm(-3) was achieved at T-Si = 1120 degrees C. and the concentration decreased with further increases in T-Si. The flat band potential was calculated and used to estimate the conduction and valence hand edge potentials of the Si-doped InGaN-based NWs, The band edge potentials were found to seamlessly straddle the redox potentials of water splitting. The linear scan voltammetry results were consistent with the estimated carrier concentration. The InGaN-based NWs doped with Si at T-Si = 1120 degrees C exhibited almost 9 times higher current density than that of the undoped sample and a stoichiometric evolution of hydrogen and oxygen gases. Our systematic findings suggest that the PEC performance can be significantly improved by optimizing the Si doping level of InGaN-based NW photoanodes. (C) 2018 Author(s).