Enhancement of p-NiO/i-ZnO nanorods/n-ZnO ultraviolet detectors through the incorporation of ZnO nanorods

An optically transparent p-NiO/i-ZnO nanorods/n-ZnO heterojunction device was been successfully constructed to be ultraviolet (UV) photodiodes by r.f. magnetron sputtering system. The ZnO nanorods, which are distinguished by their clearly defined hexagonal facets aligned with the (002) crystallographic direction, demonstrated a growth pattern that is nearly vertical when deposited on the ZnO films. The current-voltage (I–V) demonstrate a rectifying behavior that is characteristic of diode operation. The turn-on voltage and reverse leakage current density of the p-NiO/n-ZnO heterojunction are approximately 0.53 V and 3.03 × 10⁻⁸ A/cm² at a reverse bias of −1 V, respectively. When employing ZnO nanorods as the intrinsic layer, the measured turn-on voltage is 1.79 V, while the reverse leakage current density is recorded as 1.01 × 10⁻⁹ A/cm².The diminished dark current and improved photosensitivity noted in the p-NiO/i-ZnO nanorods/n-ZnO heterojunction device can be ascribed to the elevated surface-to-volume ratio of the ZnO nanorods. The results indicate that this particular structure is appropriate for applications involving ultraviolet detection.