The role of different initial rest times on synthesized buffer layer and UV sensing of ZnO nanorods grown on rotational substrate

چکیده مقاله

ZnO nanorods (NRs) were successfully synthesized on seed layered substrate by a rotational hydrothermal method. The critical role of initial rest time of rotating substrate on the growth and UV photodetecting properties of ZnO NRs was systematically investigated. Moreover, the crystal structure and morphology of as-grown ZnO NRs were characterized by X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM), respectively. The XRD studies showed that the c-oriented (002) peak of ZnO NRs was shifted towards higher values with increasing initial rest time while the grain size decreased. Interestingly, the diameter and length of NRs displayed increasing trend with increasing the initial rest time which makes them tunable nanostructures through facile hydrothermal-based fabrication process. The change in the electrical resistance of the samples was described according to morphological specification of NRs and buffer layer thickness which was ascribed to the transport mechanism of electrons in the synthesized buffer layer. Finally, photosensing properties of ZnO based ultraviolet (UV) detectors were evaluated. Accordingly, it was observed the photodetector with optimal performance (20 min initial time) shows an optimum sensitivity of ~1270 and responsivity of ~1.18 A/W.