Iodine-assisted ultrafast growth of high-quality monolayer MoS2with sulfur-terminated edges

Two-dimensional (2D) semiconductors have attracted great attention to extend Moore’s law, which motivates the quest for fast growth of high-quality materials. However, taking MoS2as an example, current methods yield 2D MoS2with a low growth rate and poor quality with vacancy concentrations three to five orders of magnitude higher than silicon and other commercial semiconductors. Here, we develop a strategy of using an intermediate product of iodine as a transport agent to carry metal precursors efficiently for ultrafast growth of high-quality MoS2. The grown MoS2has the lowest density of sulfur vacancies (~1.41×1012cm−2) reported so far and excellent electrical properties with high on/off current ratios of 108and carrier mobility of 175 cm2V−1s−1. Theoretical calculations show that by incorporating iodine, the nucleation barrier of MoS2growth with sulfur-terminated edges reduces dramatically. The sufficient supply of precursor and low nucleation energy together boost the ultrafast growth of sub-millimeter MoS2domains within seconds. This work provides an effective method for the ultrafast growth of 2D semiconductors with high quality, which will promote their applications.