Direct Growth of Lateral ZnO Nanorod UV Photodetectors with Schottky Contact by a Single-Step Hydrothermal Reaction

Lateral zinc oxide (ZnO) nanorod metal-semiconductor-metal ultraviolet detectors with different metal contact were fabricated on glass substrate by a single-step hydrothermal reaction. With the combined effect from a ZnO seed layer and an inactive layer for nanorod growth, ZnO nanorods could grow laterally and aligned between the interdigitated electrodes. When the growth process is terminated, the integration of ZnO nanorods into a function device can be achieved in the meantime. The structure can be modeled as being composed of two same Schottky barriers connected back to back, in series with a resistance of R. The devices are visible-blind and have great response even in mid ultraviolet region. The photodetectors with Ni electrode show better performance both in the aspect of photocurrent and response time, owing to the larger Schottky barrier at the Ni/ZnO interface. By surface coating with polymethyl methacrylate, the response has been further improved. Our approach provides a simple and effective way to fabricate high performance ultraviolet detectors.