Low-Cost UV-IR Dual Band Detector Using Nonporous ZnO Film Sensitized by PbS Quantum Dots

A low-cost photoconductive dual-band detector was prepared using a nanoporous ZnO film sensitized by PbS quantum dots (QDs). At room temperature the device shows a UV response in the wavelength range of 200-400 nm with a 370 nm peak responsivity of 4.0×10⁵ V/W and a vis-NIR response from 500 to 1400 nm with a 700 nm peak responsivity of 5.4×10⁵ V/W. By increasing the size of the PbS QD, the response can be extended up to 2.9 μm. It is suggested that the UV response is a result of interband absorption of UV radiation by ZnO and the IR response comes from the absorption of PbS QDs.