A new strategy to improve the performance of MoS2-based 2D photodetector by synergism of colloidal CuInS2 quantum dots and surface plasma resonance of noble metal nanoparticles

Abstract

Owing to their extraordinary optoelectronic properties, 2D transition metal dichalcogenides (TMDs) are proved to be promising materials for photodetectors. However, they suffered from poor absorptivity due to their atomically thin profile. Herein, CuInS2 quantum dots (QDs) and plasmonic Au nanoparticles (AuNPs) were adopted to achieve a MoS2-CuInS2-AuNPs 2D–0D hybrid by simultaneous deposition of CuInS2 QDs and AuNPs on the MoS2 nanosheet. In this configuration, MoS2 is used as a high mobility carrier transport channel, while CuInS2 QDs act as an efficient light absorber, and the AuNPs serve as a light sensitizer to enhance the local electric field around MoS2 and CuInS2 QDs via surface plasmon resonance (SPR). With such synergism of CuInS2 QDs and Au NPs, the highest responsivity of 16.65AW−1 and D* as high as 2.27×1012Jones are achieved for the MoS2-CuInS2-AuNPs hybrid devices under 635 nm laser, which is two orders of magnitude higher than the pristine MoS2 devices and outperformed most of the other MoS2-based photodetectors. Finally, the synergistic effect of the CuInS2 QDs and Au nanoparticles is illustrated by Finite-Difference Time-domain(FDTD) simulation. The underlying synergism strategy for such a 2D–0D configuration may also be applied to other photo-electric devices.