Optimizing ZnO Nanorod Sensors: the Influence Etching Time on Morphology and UV Sensitivity

Abstract

Zinc oxide (ZnO) nanorods, synthesized using a hydrothermal method, were etched in a solution containing ZnO nanopowder for varying durations. The morphological and structural features of the etched ZnO nanorods were characterized using field-emission scanning electron microscopy (FESEM) and X-ray diffraction (XRD). FESEM images showed a reduction in both the diameter and length of the nanorods with increasing etching time. Additionally, XRD results revealed a significant decrease in the intensity of the (002) peak as etching time increased. Furthermore, the electrical resistance of the sensors exhibited a substantial increase with prolonged etching time. The sensing properties were enhanced by the etching process; notably, the ZnO nanorods etched for 3 h showed excellent UV photoresponsivity and sensitivity, with values of 6.52 A/W and 2.4×105, respectively. This represents a significant improvement over the unetched nanorods, which exhibited values of 0.67 A/W and 420.