PbS-Decorated WS₂ Phototransistors with\nFast Response

Abstract

Tungsten disulfide (WS₂), as a typical metal dichalcogenides\n(TMDs), has aroused keen research interests in photodetection. Here,\nfield effect phototransistors (FE_pTs) based on heterojunction\nbetween monolayer WS₂ and PbS colloidal quantum dots are\ndemonstrated to show high photoresponsivity (up to ∼14 A/W),\nwide electric bandwidth (∼396 Hz), and excellent stability.\nMeanwhile, the devices exhibit fast photoresponse times of ∼153\nμs (rise time) and ∼226 μs (fall time) due to the\nassistance of heterojunction on the transfer of photoexcitons. Therefore,\nexcellent device performances strongly underscore monolayer WS₂–PbS quantum dot as a promising material for future\nphotoelectronic applications.