Characteristics of Ga-doped ZnO thin-film ultraviolet photodetectors fabricated on patterned Si substrate

Ultraviolet (UV) photodetectors have demonstrated wide applications in both civil and military fields such as pollution monitoring and missile warning. ZnO-based UV photodetectors have attracted tremendous attention due to the advantages of low cost and high chemical and thermal stability. In this work, Ga-doped ZnO (GZO) films were grown with the technique of RF magnetron sputtering and metal-semiconductor-metal (MSM) UV detectors were fabricated with the GZO films as the active detection layers. The as-sputtered films were further treated by the means of thermal annealing such that reduced oxygen vacancy and improved crystallization were achieved for the films. The effect of patterned Si substrates on the GZO UV detectors performance was revealed for the first time. With optimized annealing temperature and delicately designed substrate patterns, the responsibility of GZO MSM photodetectors has been greatly enhanced (e.g. about 2.5-folds higher than ones fabricated on non-patterned Si substrate). Our work on the GZO material and the structural design may pave a new way towards developing low-cost but high-performance UV detectors.