Zinc Oxide Nanowire As an Electron-Extraction Layer for Broadband Polymer Photodetectors with an Inverted Device Structure

We report the fabrication of high-performance broadband polymer photodetectors based on narrow bandgap conjugated polymers with an inverted device structure, where electrons and holes are collected on indium tin oxide and metal contact with high work function. High-quality wide bandgap vertically aligned ZnO nanowire array offers an enhanced surface area and is used as the cathode buffer layer in this device for effectively extracting electrons and blocking holes from the active polymer layer. The room-temperature detectivity of polymer photodetectors with such an inverted device structure is greater than 10(10) Jones with the spectral response from 400 to 1450 nm. Our results define a promising pathway for fabrication of high-sensitivity polymer photodetectors with an inverted device structure using ZnO nanowire array cathode buffer layer for a wide range of applications.