Engineering Vertically Aligned ZnO Nanorods with Amorphous IGZO for High-Performance UV Photodetection

Ultraviolet photodetectors with low dark current and high photoresponse are still difficult to fabricate in a simple device architecture. Here, we report a ZnO nanorod/IGZO/n-Si heterostructure in which the amorphous indium gallium zinc oxide (IGZO) interlayer serves as a wide-bandgap carrier-transport and leakage-suppression layer between the UV-absorbing ZnO nanorods and the Si substrate. It was fabricated through a low-temperature process that combines Radio Frequency (RF) sputtering and hydrothermal growth. The ZnR/IGZO device exhibited substantially lower dark current while maintaining a strong UV photoresponse compared with the reference structures. Structural and optical analyses confirm the phase quality of the ZnO nanorods and the distinct roles of the two oxide layers in the heterostructure. Under UV illumination, the device exhibits a dark current of 6.02 × 10–9 A and a photocurrent of 9.57 × 10–5 A, together with a large photo-to-dark current ratio and stable switching behavior. These results show that introducing IGZO as an interfacial transport layer provides an effective strategy for simultaneously suppressing leakage current and maintaining strong photoresponse in ZnO nanorod-based UV photodetectors. These results provide a straightforward route toward oxide-based UV photodetectors and highlight the importance of controlling morphology and interface properties in simple photodetector architectures.