We report the fabrication of a double Schottky barrier (DSB) device by self-assembly of nanowires (NWs). The operating principle of the device is governed by the surface depletion effects of the NWs. High DSBs were formed at the contact interface of ZnO NWs self-assembled into bascule nanobridge (NB) structures. The bascule NB structures exhibited high sensitivity and fast response to UV illumination, having a photocurrent to dark current ratio > 10(4) and a recovery time as short as approximately 3 s. The enhanced UV photoresponse of the bascule NB structure is ascribed to the DSB, whose height is tunable with UV light, being high (approximately 0.77 eV) in dark and low under UV. The bascule NB structure provides a new type of optical switch for spectrally selective light sensing applications ranging from environmental monitoring to optical communication.