Dependence of photocurrent on UV wavelength in ZnO/Pt bottom-contact Schottky diode

Abstract We fabricated the bottom-contacted ZnO/Pt Schottky diode and investigated the dependence of its photocurrent on the wavelength of illuminated ultraviolet (UV) light source. The bottom-contacted Schottky diode was devised by growing (000 l ) ZnO on (111) Pt, and the fabricated device showed a strong dependence on the UV wavelength for its photo-response characteristics. When longer-wavelength-UV ( e.g. , UV-A) was illuminated on the device, the photo-current was increased by a factor of 200, compared to that under illumination of shorter-wavelength-UV ( e.g. , UV-C). The behavior is attributed to the wavelength-dependent UV penetration depth for ZnO.