Low Noise and Fast Photoresponse of Few-Layered MoS2 Passivated by MA3Bi2Br9

Two-dimensional (2D) transition metal dichalcogenides (TMDs) have been widely used in electronic and optoelectronic devices. However, 2D TMDs suffer from surface defects and ambient gas absorption, which significantly degrade their electronic and optoelectronic properties. Here we revealed the passivation effect of methylamine (MA) halide on molybdenum disulfide (MoS2) in the outstanding lead-based/MoS2 hybrid structure. Lead-free MA3Bi2Br9 with a high-crystalline quasi-layered structure was used to prolong the MABr passivation effect on MoS2. As a result, MA3Bi2Br9-coated MoS2 photodetector achieved the fastest response time of 0.3 ms and the highest detectivity of 3.8 × 1012 Jones among the reported MoS2-based photodetectors so far. This photodetector also showed high photoresponse stability.