High-Field Transport and Velocity Saturation in Synthetic Monolayer MoS2.

Two-dimensional semiconductors such as monolayer MoS2 are of interest for future applications including flexible electronics and end-of-roadmap technologies. Most research to date has focused on low-field mobility, but the peak current-driving ability of transistors is limited by the high-field saturation drift velocity, vsat. Here, we measure high-field transport as a function of temperature for the first time in high-quality synthetic monolayer MoS2. We find that in typical device geometries (e.g. on SiO2 substrates) self-heating can significantly reduce current drive during high-field operation. However, with measurements at varying ambient temperature (from 100 to 300 K), we extract electron vsat = (3.4 ± 0.4) × 106 cm/s at room temperature in this three-atom-thick semiconductor, which we benchmark against other bulk and layered materials. With these results, we estimate that the saturation current in monolayer MoS2 could exceed 1 mA/μm at room temperature, in digital circuits with near-ideal thermal management.