Sub-nano cluster decoration for the manipulation of the photogenerated carrier behavior of MoS₂

Abstract

For most applications based on the photoelectric effect, uncontrollable photogenerated carrier behavior, such as trapping and recombination, is a common issue that reduces the carrier utilization efficiency. Herein, a sub-nano cluster (Pd, Ru, and PdRu alloy) decoration strategy is proposed to manipulate the photogenerated carrier behavior in MoS₂ to optimize the optoelectronic properties. After decoration, electrons can flow into sub-nano cluster through Pd—S bonds and then return to MoS₂ through Ru—S bonds at the sub-nano cluster/MoS₂ interface when holes are left in the channel for collection to achieve efficient carrier separation. In addition, the formation of metal—S bonds also leads to the generation of mid-gap states, which enables light absorption over a wide wavelength range. Therefore, the photodetector based on PdRu/MoS₂ shows broadband photodetection ability from 532 to 1550 nm with high responsivity/external quantum efficiency of 310.8 A W^–1/7 × 10⁴% (532 nm), 4.2 A W^–1/527% (980 nm), and 7.14 mA W^–1/0.5% (1550 nm), as well as a fast response speed (rise/decay time of 11.5/12.0 ms). Our work offers new insight into manipulating the photogenerated carrier behavior to optimize the performance of semiconducting 2D materials for practical optoelectronic applications.

Keywords

2D materials / carriers / clusters / optoelectronic materials