High-performance ZnO/Ag Nanowire/ZnO composite film UV photodetectors with large area and low operating voltage

Abstract

A simple and low-cost solution-processed method is used to fabricate ZnO/Ag nanowire/ZnO composite UV photodetectors with a large area of 4 × 5 mm², low operating voltage of 1 V and high visible transmittance of 75%. Due to the low-dimensionality confinement ability and small persistent photoconductivity effect in polycrystalline ZnO nanoparticle thin films and excellent conductivity of Ag nanowire networks, composite UV photodetectors exhibit a high on/off ratio and short response time under high light illumination, while exhibiting large detectivity and responsivity under low light illumination. Compared with traditional polycrystalline ZnO thin films, the formation of a large number of Ohmic contacts between ZnO nanoparticles and Ag nanowires in a composite structure greatly improves the extraction number and shortens the extraction time of photoelectrons. Additionally, both Schottky contact and Ohmic contact at the electrode interface can obtain a high on/off ratio and short response time. Our composite structure device is regarded as a compromise between high-performance with large-area, low-voltage and low-cost. It has many advantages compared with its counterparts include ZnO nanowires, and other ZnO composites, which is very promising in UV photodetective applications.