Few‐Layered PtS2 Phototransistor on h‐BN with High Gain

The very recently rediscovered group‐10 transition metal dichalcogenides (TMDs) such as PtS 2 and PtSe 2 , have joined the 2D material family as potentially promising candidates for electronic and optoeletronic applications due to their theoretically high carrier mobility, widely tunable bandgap, and ultrastability. Here, the first exploration of optoelectronic application based on few‐layered PtS 2 using h‐BN as substrate is presented. The phototransistor exhibits high responsivity up to 1.56 × 10 3 A W −1 and detectivity of 2.9 × 10 11 Jones. Additionally, an ultrahigh photogain ≈2 × 10 6 is obtained at a gate voltage V g = 30 V, one of the highest gain among 2D photodetectors, which is attributed to the existence of trap states. More interestingly, the few‐layered PtS 2 phototransistor shows a back gate modulated photocurrent generation mechanism, that is, from the photoconductive effect dominant to photogating effect dominant via tuning the gate voltage from the OFF state to the ON state. Such good properties combined with gate‐controlled photoresponse of PtS 2 make it a competitive candidate for future 2D optoelectronic applications.