Au/Ga₂O₃/ZnO heterostructure nanorods arrays for effective photoelectrochemical water splitting

Heterostructure semiconductors are considered as suitable candidates for solar-driven photo-electrochemical (PEC) water splitting due to their viable photoactive nature. Therefore, in this article, we have demonstrated the synthesis of Ga₂O₃/ZnO nanorods arrays (NRAs) by two-step physical vapor deposition (PVD) and wet chemistry method, directly on the glass and indium tin oxide (ITO) support. Morphological features, structural properties and chemical composition were investigated by scanning electron microscopy (FESEM), X-ray diffraction (XRD) spectroscopy and EDX, respectively. The optical properties through photoluminescence (PL) revealed that with increasing concentration of gallium content, reduction of visible peak of the PL spectrum is observed. Additionally, an ultra-thin nanofilm of gold nanoparticles (AuNPs) is also sputtered on the Ga₂O₃/ZnO NRAs to make Au/Ga₂O₃/ZnO heterostructures photoanodes. These photoanodes successfully split water under artificial solar light. Our results indicated the Au/Ga₂O₃/ZnO NRAs heterostructure photoanodes, which assimilates two different semiconductors with tunable band gaps can be realistically applied to photoelectrochemical applications.