Sub 0.5 Volt Graphene-hBN van der Waals Nanoelectromechanical (NEM) Switches

The Nanoelectromechanical (NEM) switches are a promising candidate to overcome the physical limitations of the complementary metal-oxide-semiconductor (CMOS) switches due to their quasi-zero leakage behavior, sub-thermal switching, and suitability to operate in harsh environments. The main obstacles affecting NEM switches are their irreversible switch-contact stiction, the large switching voltage, and its hysteretic loop. In this study, the irreversible static friction is overcome by employing the weak van der Waals (vdW) bonding of graphene-hexagonal boron nitride (hBN) contact in the Graphene NEM (GNEM) switches. These vdW switches show sub-0.5 V switching voltage with an ON/OFF ratio higher than 105 and nearly zero hysteretic window characteristics with a high endurance of over 50 000 switching cycles. These remarkable performances are achieved by exploiting graphene's monolayer thickness, high Young's modulus, cubic mechanical restoring force, and low vdW binding energy characteristics. As chemical vapor deposition graphene and hBN are used in these GNEM switches, it exhibits the prospect for large-scale graphene NEM system applications. These GNEM switches can be potentially used in ultralow-power CMOS integrated circuits, hybrid NEM-CMOS systems, logic devices, NEM resonator mass sensing, and single-molecule sensors.