UV Photodetecting Performance Analysis of Zno Nanorod Arrays Grown on Rotating Substrate: Evaluation of the Initial Rest Time

Abstract

ZnO nanorods (NRs) were successfully synthesized on seed layered substrate by a novel rotational hydrothermal method. The effect of rotational substrate initial rest time on the growth of ZnO NRs were systematically characterized by X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM). The X-ray diffraction studies showed that the (002) peak height of ZnO NRs was shifted towards higher values with increasing initial rest time while the grain size decreased. The NRs diameter and length displayed increasing trend. The optical studies indicated that with increase of the initial rest time, the band gap of the ZnO NRs decreased from ~ 3.24 eV in ZnO NRs grown on initially rotated substrate to ~ 3.18 eV in sample with initially 10 min rest time then increased to ~ 3.28 eV in sample with initially 20 min rest time. The changes of samples electrical resistances was described according to morphological specification of NRs and initial sub-layer thickness where increasing initial rest time up to 20 min improves the electrons transition in samples. Finally, photosensing properties of ZnO based ultraviolet (UV) detectors were investigated. It was observed the photdetector based on ZnO NRs grown by 20 min initial rest time shows an optimum performance with sensitivity ~1270 and responsivity ~1.18 A/W