The industry is now tooling up for wide band gap-semiconductors such as Zinc-Oxide (ZnO). Besides a wide band gap they also possess properties in optical and electrical characteristics. Only their direct band gap allows easier integration with other optical devices. As a conductivity control has been established, so the p-n junction devices are commercially available.But the global research interest in wide band gap semiconductors has been attracted towards zinc oxide (ZnO) due to its properties as a semiconductor material. The high electron mobility, high thermal conductivity, good transparency, wide direct band gap, and easiness of growing it in the nano structure form make ZnO suitable for optoelectronics, sensing, light-emitting diodes, lasers diodes, photodetectors. Also ZnO is transparent and electrically conductive, making it an ideal material for solar cell windows In photodetectors applications ZnO had intensive studies to improve the responsivity and stability of UV photodetector, due to its strong UV photoresponse and is very promising material because it is a direct wide band gap semiconductor material which can be used for UV photon detection .