Controllable growth of bilayer MoS2 crystals by reverse-flow chemical vapor deposition

Abstract

Molybdenum disulfide (MoS2) is a two-dimensional (2D) semiconductor, which shows potential applications in catalysis, optoelectronics and electronics. The stacking order in layered materials induces different performances in interlayer couplings and electronic devices. Therefore, controlling the stacking orientations is necessary but remains a significant challenge. Here uniform and high-quality bilayer MoS2 flakes (AA/AB) have been synthesized by reverse-flow chemical vapor deposition (CVD), through controlling growth temperatures. 770 °C is suitable for the growth of AA stacking and AB stacking prefers higher temperature at 820 °C. The reverse-flow helps to generate bilayer MoS2 with few nucleation points and the general method for the synthesis of bilayer MoS2 in different stacking orientations paves a way for development of 2D semiconductor applications.