Novel Exfoliation of High-Quality 2H-MoS₂ Nanoflakes for Solution-Processed Photodetector

Highly dispersive molybdenum disulfide nanoflakes (MoS₂ NFs), without any phase transition during the exfoliation process, are desirable for full utilization of their semiconductor properties in practical applications. Here, we demonstrate an innovate approach for fabricating MoS₂ NFs by using hydrazine-assisted ball milling via the synergetic effect of chemical intercalation and mechanical exfoliation. The NFs obtained have a lateral size of 600-800 nm, a thickness less than 3 nm, and high crystallinity in the 2H semiconducting phase. They form a stable dispersion in various solvents, which will be helpful for many applications, due to the oxygen functional group. To investigate production of a two-dimensional (2D) photodetector, 2D semiconducting MoS₂, MoS₂-p-Si vertical devices were fabricated, and their optical properties were characterized. The photodiode exhibited consistent responses with excellent photo-switching characteristics with wavelengths of 850, 530, and 400 nm.