Enhancement of photodetection by PbSe quantum dots on atomic-layered GeS devices

Abstract

Hybrid structures of quantum dots (QDs) on two-dimensional materials have aroused great interest because of their high absorbance properties and tunable wavelength detection ranges. In this work, 1.44 times the photoresponse bandwidth of PbSe QDs on atomic-layered GeS hybrid structure devices is achieved compared with pure GeS devices due to the transfer of photogenerated carriers between the PbSe QDs and the GeS film. A doubling of the peak photoresponsivity is obtained at a wavelength of 635 nm, and the detectivity of the hybrid devices increases by 39.5 and 27.4 times under 808 and 980 nm illumination, respectively. Additionally, tripling of the carrier mobility is measured in the hybrid devices (165.2 cm2 V−1 s−1) compared with that of pure atomic-layered GeS devices (54.2 cm2 V−1 s−1). The concentration of PbSe QDs on the GeS films is optimized for the highest photoresponsivity and carrier mobility of the hybrid devices. The results indicate that a hybrid structure of QDs on atomic-layered materials is a promising way to enhance photodetection.