High-performance deep ultraviolet photodetectors based on ZnO quantum dot assemblies

A high-performance ZnO quantum dots (QDs)-based ultraviolet (UV) photodetector has been successfully fabricated via the self-assembly of QDs on the Au interdigital electrode. The broadened band gap in ZnO QDs makes the device has the highly selective response for the deep UV detection. The unique QD-QD junction barriers similar to back-to-back Schottky barriers dominate the conductance of the QD network and the UV light-induced barrier-height modulation plays a crucial role in enhancing the photoresponsivity and the response speed. Typically, the as-fabricated device exhibits the fast response and recovery times of within 1 s, the deep UV selectivity of less than 340 nm, and the stable repeatability with on/off current ratio over 103, photoresponsivity of 5.04 × 102 A/W, and photocurrent gain of 1.93 × 103, demonstrating that the ZnO QD network is a superior building block for deep UV photodetectors.