Cadmium selenide/lead sulfide quantum dot film for high performance and broadband photodetectors

Abstract

Cadmium selenide (CdSe) possesses unique physical and chemical properties, and its high light absorption and high carrier mobility give it significant research prospects in the field of optoelectronic applications. However, the limitations of its energy band structure make it difficult to achieve high performance and broadband photodetection applications. Here, we report a hybrid photodetector prepared by spin-coating PbS quantum dots on CdSe nanocrystalline film that exhibits excellent optoelectronic properties. The prepared CdSe/PbS QD photodetector has a broad photoresponse from visible (450 nm) to near-infrared (1050 nm). Under the light irradiation at 660 nm (incident light power 27.8 μW/cm²) with bias voltage 2.0 V, the responsivity reaches 58.6 A/W, and the specific detectivity reaches up to 1.02 × 10¹² Jones. In addition, the photodetector has a fast response time, with a rise time of 0.44 ms and a fall time of 0.553 ms. The CdSe/PbS QD photodetector offers promising prospects for applications in broadband photodetection and imaging sensor in the future.