Researchers from the University of California, Riverside (UCR) and the University of Georgia have made use of three 2D materials graphene, tantalum sulphide and boron nitrate to create a simple, compact and fast voltage controlled oscillator (VCO). According to the team, this is the first useful device that exploits the potential of charge density waves to modulate an electrical current through a 2D material.
Apart from having the potential of being an ultralow power alternative to silicon based devices, the device is thin and flexible, making it suitable for use in wearable technologies. But graphene’s potential has been limited by its inability to function as a semiconductor, and the researchers attempted to overcome this by adding tantalum sulphide (TaS2), which has been shown to act as an electrical switch at room temperature. The researchers then coated TaS2 with hexagonal boron nitrate to prevent oxidation. In the design, graphene functions as an integrated tunable load resistor, which enables precise voltage control of the current and VCO frequency.