Optoelectronic Characteristics of UV Photodetector Based on GaN/ZnO Nanorods p-i-n Heterostructures

We demonstrate an efficient ultraviolet (UV) photodetector operating at room temperature based on n-ZnO nanorods/i-ZnO/p-GaN heterojunctions. We employ x-ray diffraction and field-emission scanning electron microscopy to confirm the high quality of the ZnO nanorods using an undoped ZnO film as the interlayer. Then, we investigate the photoelectric properties of the fabricated photodetector with UV light illumination under a different reverse bias. Based on the current-voltage curve, the photocurrent to dark current ratio is approximately 73.3 at -4 V. At zero-bias voltage, the peak responsivity was 138.9 mA/W at 362 nm under front-illumination conditions. Time-varying measurements indicate the reproducibility and stability of the heterojunction photodetector.