Iodine-assisted ultrafast growth of high-quality monolayer MoS<sub>2</sub> with sulfur-terminated edges

Abstract

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 MoS2 as an example, current methods yield 2D MoS2 with 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 intermediate product of iodine as a transport agent to carry metal precursors efficiently for ultrafast growth of high-quality MoS2. The grown MoS2 has the lowest density of sulfur vacancies (~ 1.41 × 1012 cm-2) reported so far and excellent electrical properties with high on/off current ratios of 108 and carrier mobility of 175 cm2V-1s-1. Theoretical calculations show that by incorporating iodine, the nucleation barrier of MoS2 growth with sulfur-terminated edges reduces dramatically. The sufficient supply of precursor and low nucleation energy together boost the ultrafast growth of sub-millimeter MoS2 domains within seconds. This work provides an effective method for ultrafast growth of 2D semiconductors with high quality, which will promote their applications.