Growth of bilayer MoS2 flakes by reverse flow chemical vapor deposition

In this work, we report on the low temperature growth of bilayer MoS2 by reverse flow chemical vapor deposition (CVD) with MoO3 and S powder as precursors, respectively, while reverse flow is facilitated by adding a one-end sealed small quartz tube inside the CVD setup. Most of the as-grown flakes are bilayer MoS2 with a high yield of 85 % in the statistical analysis. Field effect transistors (FET) based on as-grown bilayer MoS2 flakes behave as n -type semiconductors with a switching ratio of-105 as well as carrier mobility of-3.2 cm2 V-1 s-1. This work demonstrates a promising simple approach to grow bilayer flakes of other two-dimensional materials such as MoSe2, WS2, and their heterostructures.