Electret Modulation Strategy to Enhance the Photosensitivity Performance of Two-Dimensional Molybdenum Sulfide

Due to the limited light absorption efficiency of atomic thickness layers and the existence of quenching effects, photodetectors solely made of transition metal dichalcogenides (TMDs) have exhibited an unsatisfactory detection performance. In this article, electret/TMD hybridized devices were proposed by vertically coupling a MoS₂ channel and the PTFE film, which reveals an optimized photodetection behavior. Negative charges were generated in the PTFE layer through the corona charging method, akin to applying a negative bias on the MoS₂ channel in lieu of a traditional voltage-driven back gate. Under a charging voltage of -6 kV, PTFE/MoS₂ devices reveal improved photodetection performance (R_hybrid = 67.95A/W versus R_only = 3.37 A/W, at 470 nm, 1.20 mW cm^-2) and faster recovery speed (τ_d(hybrid) = 2000 ms versus τ_d(only) = 2900 ms) compared to those bare MoS₂ counterparts. The optimal detection performance (2 orders of magnitude) was obtained when the charging voltage was -2 kV, limited by the minimum of the carrier density in MoS₂ channels. This study provides an alternative strategy to optimize optoelectronic devices based on the 2D components through non-voltage-driven gating.