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

Li, Xuefei; Shi, Xinhang; Marian, Damiano; Soriano, David; Cusati, Teresa; Iannaccone, Giuseppe; Fiori, Gianluca; Guo, Qi et al. · Sci Adv · 2023

basic_science · Level V

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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 WS<sub>2</sub> (WSe<sub>2</sub>) is 65% (50%) higher than that of 2H WS<sub>2</sub> (WSe<sub>2</sub>). The 3R bilayer WS<sub>2</sub> n-type FET exhibits a high on-state current of 480 μA/μm at <i>V</i><sub>ds</sub> = 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.