High performance photodetector based on few-layer MoTe_(2)/CdS_(0.42)Se_(0.58) flake heterojunction

Two-dimensional(2D)transition metal dichalcogenides have been extensively studied due to their fascinating physical properties for constructing high-performance photodetectors.However,their relatively low responsivities,current on/off ratios and response speeds have hindered their widespread application.Herein,we fabricated a high-performance photodetector based on few-layer MoTe_(2) and CdS_(0.42)Se_(0.58) flake heterojunctions.The photodetector exhibited a high responsivity of 7221 A/W,a large current on/off ratio of 1.73×10^(4),a fast response speed of 90/120μs,external quantum efficiency(EQE)reaching up to 1.52×10^(6)%and detectivity(D*)reaching up to 1.67×10^(15) Jones.The excellent performance of the heterojunction photodetector was analyzed by a photocurrent mapping test and first-principle calculations.Notably,the visible light imaging function was successfully attained on the MoTe_(2)/CdS_(0.42)Se_(0.58) photodetectors,indicating that the device had practical imaging application prospects.Our findings provide a reference for the design of ultrahighperformance MoTe_(2)-based photodetectors.

Enhanced optoelectronic characteristics of MoS_(2)-based photodetectors through hybridization with CdS_(0.42)Se_(0.58)nanobelt

Monolayer molybdenum disulfide(MoS_(2))has weak light absorption due to its atomically-thin thickness,thus hindering the development of MoS_(2)-based optoelectronic devices.CdS_(x)Se_(1-x)has excellent photoelectric performance in the visible light range,and its nanostructure shows great potential in new nanoscale electronic and optoelectronic devices.In this work,a composite photodetector device with the combination of monolayer MoS_(2)nanosheets and CdS_(0.42)Se_(0.58)nanobelts has been successfully prepared,which can not only maintain the inherent excellent properties of the two blocks,but also play a synergistic role between them,thus improving the photoelectric performance of the device.The monolayer MoS_(2)nanosheet/CdS_(0.42)Se_(0.58)nanobelt photodetector has a wide spectral response range(400–800 nm),high responsivity(527.22 A/W)and large external quantum efficiency(EQE)(1.06×10^(5)%).Compared with the isolated monolayer MoS_(2)nanosheet,both the responsivity and EQE of the hybrid photodetector are increased by 117.4 times under 620 nm illumination.This study provides a way to prepare hybrid photodetectors with wide spectral response and high responsivity.