Growth of gallium nitride nanowires on sapphire and silicon by chemical vapor deposition for water splitting applications

Gallium nitride (GaN) nanowires (NWs) are one of the most promising candidates for photoelectrode materials due to their tunable band edge potentials and high stability in electrolytes. In this study, GaN NWs were grown on sapphire (Al2O3) (002) and silicon (Si) (111) substrate by chemical vapor deposition (CVD) method. High quality of GaN NWs on sapphire and silicon were confirmed by powder X-ray diffraction (XRD). Structural characterization of the synthesized NWs were performed using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The images revel the pristine and smooth surface of GaN NWs. Further, optical properties of GaN NWs were investigated at room temperature photoluminescence emission. The photocurrent density of GaN/Si NWs is found to be higher than that of GaN/Al2O3 NWs. The GaN/Si NWs having large surface area, are grown in a much simpler method. GaN/Si NWs are potential candidate for hydrogen energy generation, due to their enhanced water splitting efficiency by utilizing solar energy.