Observation of photocurrent generation in electrodeposited zinc oxide layers

Wurtzite zinc oxide (ZnO) films with band gap energy of about 3.3 eV were d eposited onto conductive substrates by electrodeposition from a simple aque ous zinc nitrate solution at 335 K. The films showed optical transmission a round 70% in the visible light region. The electrical resistance showed a s trong dependence on cathodic potential. The decrease in electrical resistan ce could be observed with light irradiation irrespective of the cathodic po tential and was attributed to the excitation of electrons from valence band to conduction band by light with wavelength below 375 nm. A photocurrent o f about 0.10 mu A was generated for a cell composed of Ag electrode/Au/ZnO/ NESA glass substrate under conditions of irradiation by sunlight.