ZnO has been studied extensively for several applications

such as surface-acoustic-wave devices

ultraviolet light-emitting devices

laser diodes and gas sensors. Apart from these

high quality ZnO films are promising for UV photodetector application due to their wide and direct band gap and large photoresponse. Compared with photoconductive detector

Schottky type photodetectors are more attractive due to their high speed and low noise performance. Previously reported Schottky barrier UV sensitive photodiodes exhibited low quantum efficiency due to a large amount of recombination centers in the polycrystalline ZnO layers. In this paper

hexagonal microtube ZnO was firstly grown on single crystal p-Si(111) substrates by hydrothermal method. The Ag film electrodes was deposited on ZnO by planar magnetron sputtering

therefore Ag/n-ZnO UV photodetector was fabricated. The characteristic of dark- and photo-current of Ag/n-ZnO Schottky UV photodetector

the UV photoresponse and the quantum efficiency of the detector were also investigated. The results of testing indicate that there is a good Schottky behavior between Ag and microtube ZnO

and an effective barrier height is 0.35 eV. Dark current was very small

without illumination. Under illumination using monochromatic light with a wavelength of 365 nm

photogenerated current arrived at 25.6 and 57.9 μA

at a bias of 5 V and 9 V

respectively. A evident wide-range spectral responsivity and higher quantum efficiency of (Ag/n-ZnO) detector were observed. The maximum photo-responsibility of 0.161 A/W and the quantum efficiency of (54.7%) were obtained at wavelength of 366 nm. Therefore

the hexagonal microtube ZnO is suitable to apply for UV photodetector.