Enhanced Photosensitivity in Monolayer MoS2 with PbS Quantum Dots

Abstract

Photocurrent Photocurrent enhancement has been investigated in monolayer (1L) MoS2 with PbS quantum dots (QDs). A metal-semiconductor-metal (Au-1L MoS2-Au) junction device is fabricated using a standard photolithography method. Considerably improved photo-electrical properties are obtained by coating PbS QDs on the Au-1L MoS2-Au device. Time dependent photoconductivity and current-voltage characteristics are investigated. For the QDs-coated MoS2 device, it is observed that the photocurrent is considerably enhanced and the decay life time becomes longer. We propose that carriers in QDs are excited and transferred to the MoS2 channel under light illumination, improving the photocurrent of the 1L MoS2 channel. Our experimental findings suggest that two-dimensional layered semiconductor materials combined with QDs could be used as building blocks for highly-sensitive optoelectronic detectors including radiation sensors.