Ultraviolet-Infrared dual band detector using ZnO/PbS composite nanostructure*

Sensors for detecting ultraviolet (UV) and near-infrared (NIR) photons, fabricated by complex epitaxial methods are costly. A low cost UV-NIR detector is fabricated using ZnO nonporous powder and PbS quantum size particles is demonstrated. A nonporous film of ZnO was fabricated on Fluorine doped Tin Oxide (FTO) glass with a scribe, separating the FTO layer in to two electrodes. PbS quantum particles were composites on the ZnO film by wetting the film using a solution of lead acetate in ethanol and passing a stream of H$_{2}$S gas on top of the film. When a bias voltage is applied across the electrodes the device shows two response peaks, around 380nm (UV) and 800nm (NIR). These two responses are resulted due to bandgap excitation of ZnO ($\sim $3.2 eV) and PbS ($\sim $0.9 eV) quantum particles.