Low-Cost ZnO-Based Ultraviolet–Infrared Dual-Band Detector Sensitized With PbS Quantum Dots

A low-cost photoconductive dual-band detector based on a ZnO film sensitized with lead sulfide quantum dots (PbS-QDs) is reported. The UV response arises from the interband absorption of UV radiation by ZnO, and the IR response is due to the absorption in the PbS-QDs. The detector exhibits UV response from 200 to 400 nm with a peak responsivity of 4.0 × 10⁵ V/W and detectivity D* of 5.5 × 10¹¹ Jones at 370 nm at room temperature. The observed visible-near IR response is from 500 to 1400 nm with a responsivity of 5.4 × 10⁵ V/W and D* of 7.3 × 10¹¹ Jones at 700 nm operating at room temperature. By increasing the PbS-QD size, the IR response can extend up to 2.9 μm.