Iodine-assisted ultrafast growth of high-quality monolayer MoS₂ 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 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 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 cm2 V−1 s−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 the ultrafast growth of 2D semiconductors with high quality, which will promote their applications.

Keywords

• 2D semiconductors
• molybdenum disulfides
• ultrafast growth
• defect density
• sulfur vacancy
• iodine-assisted
• sulfur-terminated edge