CdS/ZnO nanocomposite film and its enhanced photoelectric response to UV and visible lights at low bias

In this paper, the CdS/ZnO nanocomposite film with enhanced photoelectric response to UV or white lights at low bias was demonstrated. The pure ZnO film was firstly fabricated by the technology of screen printing, and the CdS/ZnO film was prepared by the subsequent successive ionic layer adsorption and reaction process. XRD, UV–vis DRS, FE-SEM and EDX analysis confirmed the successful growth of CdS on the surface of ZnO nanoparticles. The photoelectric responses of ZnO and CdS/ZnO were tested under different illumination and by application of a series low bias in the gas phase. The CdS/ZnO nanocomposite film exhibited a tremendous enhancement on the photocurrent amplitude by application of a 0.01 V bias, which gave 13.3 and 153 times higher than that of the pure ZnO film under UV and white light irradiation, respectively. The mechanism for the enhanced response is attributed to the special interface between CdS and ZnO, which can efficiently suppress the recombination of photogenerated electron–hole pairs and in turn resulting in a large increase of the photocurrent in the external circuit.