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.