Rhombohedral-stacked bilayer transition metal dichalcogenides for high-performance atomically thin CMOS devices

Abstract

Van der Waals coupling with different stacking configurations is emerging as a powerful method to tune the optical and electronic properties of atomically thin two-dimensional materials. Here, we investigate 3R-stacked transition-metal dichalcogenides as a possible option for high-performance atomically thin field-effect transistors (FETs). We report that the effective mobility of 3R bilayer WS2 (WSe2) is 65% (50%) higher than that of 2H WS2 (WSe2). The 3R bilayer WS2 n-type FET exhibits a high on-state current of 480 μA/μm at Vds = 1 V and an ultralow on-state resistance of 1 kilohm·μm. Our observations, together with multiscale simulations, reveal that these improvements originate from the strong interlayer coupling in the 3R stacking, which is reflected in a higher conductance compared to the 2H stacking. Our method provides a general and scalable route toward advanced channel materials in future electronic devices for ultimate scaling, especially for complementary metal oxide semiconductor applications.