Manipulating the Light-Matter Interaction of PtS/MoS_2 p-n Junctions for High Performance Broadband Photodetection

摘要

Due to the limited carrier concentration, 2D transition metal dichalcogenides have lower intrinsic dark current, and thus, are widely studied for high performance room photodetection. However, the light-matter interaction is still unclear, thus tuning the photoexcitation and further manipulating the photodetection is a challenge. Herein, large-area PtS films are synthesized, and the growth mechanism is investigated. It is demonstrated that PtS has an orthorhombic structure and exhibits the p-type semiconducting behavior. Then, MoS2/PtS p-n heterojunction is fabricated, and its energy diagram is discussed based on the Kelvin probe force microscopy. The contact potential difference is about 160 mV, which is much larger than previous 2D junctions facilitating the charge separation. Furthermore, the phototransistor based on MoS2/PtS p-n heterojunction is prepared, showing broadband photoresponse from visible to near-infrared. The manipulation of an external field on photoresponse, detectivity, and rise/fall time are explored and discussed. The responsivity can reach up to 25.43 A W-1, and the detectivity is 8.54 x 10(12) Jones. These results indicate that PtS film is a prospective candidate for high-performance optoelectronic devices and broaden the scope of infrared detection materials.