Enhanced Photosensitivity in Monolayer MoS2 with PbS Quantum Dots

Abstract

Absract Photocurrent enhancement has been investigated in monolayer (1L) MoS 2 with PbS quantum dots (QDs).A metal-semiconductor-metal (Au-1L MoS 2 -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 MoS 2 -Au device.Time dependent photoconductivity and current-voltage characteristics are investigated.For the QDs-coated MoS 2 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 MoS 2 channel under light illumination, improving the photocurrent of the 1L MoS 2 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.