Growth of Gallium Nitride Nanowires on Sapphire and Silicon by Chemical Vapor Deposition for Water Splitting Applications

•GaN nanowires were grown on sapphire and Silicon by CVD method.•Grown GaN nanowires is high crystalline, smooth and without any impurity.•GaN nanowires are suitable material for photoanode used in water splitting.•The saturated photocurrent density increased in GaN/Si NWs than GaN/Al2O3 NWs.