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

Abstract

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 × 109 Jones to 4.38 × 1010 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.