Ultrasensitive Hybrid MoS-ZnCdSe Quantum Dot Photodetectors with High Gain.

Recently, two-dimensional (2D) materials, especially transition-metal dichalcogenides (TMDCs), have attracted extensive interest owing to their potential applications in optoelectronics. Here, we demonstrate a hybrid 2D-zero-dimensional (0D) photodetector, which consists of a single-layer or few-layer molybdenum disulfide (MoS) thin film and a thin layer of core/shell zinc cadmium selenide/zinc sulfide (ZnCdSe/ZnS) colloidal quantum dots (QDs). It is worth mentioning that the photoresponsivity of the hybrid 2D-0D photodetector is 3 orders of magnitude larger than the TMDC photodetector (from 10 to 10 A W). The detectivity of the hybrid structure detector is up to 10 Jones, and the gain is up to 10. Due to an effective energy transfer from the photoexcited QD sensitizing layer to MoS films, light absorption is enhanced and more excitons are generated. Thus, this hybrid 2D-0D photodetector takes advantage of high charge mobility in the MoS layer and efficient photon absorption/exciton generation in the QDs, which suggests their promising applications in the development of TMDC-based optoelectronic devices.