Energy transfer in hybrid 0D-CdSe quantum dot/2D-WSe2 near-infrared photodetectors

Due to the energy transfer at the interface, the quantum dots (QDs) modification of two-dimensional (2D) materials is an effective and convenient way to improve their optoelectronic properties. In this work, we have studied the influence of the CdSe QDs on the physical properties of the 2D WSe2. After the modification of CdSe QDs, the energy transfer is observed in heterostructures which confirmed by the photoluminescence and Raman results. The WSe2/CdSe QDs heterostructure based phototransistors exhibit an ambipolar characteristic, owing to the typical type-II band alignment. Under the illumination of 638 nm light, the performance of the device significantly improved compared with the WSe2 based device: the responsivity increased from 3.6 A W-1 to 9.27 A W-1; the detectivity increased from 7.73 x 10(9) Jones to 4.38 x 10(10) Jones. Meanwhile, the devices exhibit good photoresponse in a wide spectral range from visible light to near-infrared light. Our work suggests that hybridizing 0D QDs and 2D material is a suitable and effective way to enhance the photodetection ability of the device and realize the ambipolar photodetection. It is a potential way to build multifunctional optoelectronic devices with broadband and high photoresponse performances.

Automated summary

The influence of CdSe quantum dots (QDs) modification on the physical properties of 2D WSe2 was studied in this work. The energy transfer in heterostructures was observed after the modification, confirmed by photoluminescence and Raman results. The phototransistors based on the WSe2/CdSe QDs heterostructure exhibited an ambipolar characteristic and showed significant improvement in performance compared to the WSe2 based device. The hybridization of 0D QDs and 2D material is a suitable and effective approach to enhance the photodetection ability and achieve ambipolar photodetection in multifunctional optoelectronic devices.