title: A charge-density-wave oscillator based on an integrated tantalum disulfide-boron nitride-graphene device operating at room temperature.
abstract: The charge-density-wave (CDW) phase is a macroscopic quantum state consisting of a periodic modulation of the electronic charge density accompanied by a periodic distortion of the atomic lattice in quasi-1D or layered 2D metallic crystals. Several layered transition metal dichalcogenides, including 1T-TaSe2, 1T-TaS2and 1T-TiSe2exhibit unusually high transition temperatures to different CDW symmetry-reducing phases. These transitions can be affected by the environmental conditions, film thickness and applied electric bias. However, device applications of these intriguing systems at room temperature or their integration with other 2D materials have not been explored. Here, we demonstrate room-temperature current switching driven by a voltage-controlled phase transition between CDW states in films of 1T-TaS2less than 10 nm thick. We exploit the transition between the nearly commensurate and the incommensurate CDW phases, which has a transition temperature of 350 K and gives an abrupt change in current accompanied by hysteresis. An integrated graphene transistor provides a voltage-tunable, matched, low-resistance load enabling precise voltage control of the circuit. The 1T-TaS2film is capped with hexagonal boron nitride to provide protection from oxidation. The integration of these three disparate 2D materials in a way that exploits the unique properties of each yields a simple, miniaturized, voltage-controlled oscillator suitable for a variety of practical applications.
authors.affiliation: Department of Electrical and Computer Engineering, Nano-Device Laboratory (NDL) and Phonon Optimized Engineered Materials (POEM) Center, University of California - Riverside, Riverside, California 92521, USA.
authors.forename: Guanxiong
authors.initials: G
authors.lastname: Liu
authors.affiliation: Department of Electrical and Computer Engineering, Laboratory for Terascale and Terahertz Electronics (LATTE), University of California - Riverside, Riverside, California 92521, USA.
authors.forename: Bishwajit
authors.initials: B
authors.lastname: Debnath
authors.affiliation: Department of Chemistry, University of Georgia, Athens, Georgia 30602, USA.
authors.forename: Timothy R
authors.initials: TR
authors.lastname: Pope
authors.affiliation: Department of Chemistry, University of Georgia, Athens, Georgia 30602, USA.
authors.forename: Tina T
authors.initials: TT
authors.lastname: Salguero
authors.affiliation: Department of Electrical and Computer Engineering, Laboratory for Terascale and Terahertz Electronics (LATTE), University of California - Riverside, Riverside, California 92521, USA.
authors.forename: Roger K
authors.initials: RK
authors.lastname: Lake
authors.affiliation: Department of Electrical and Computer Engineering, Nano-Device Laboratory (NDL) and Phonon Optimized Engineered Materials (POEM) Center, University of California - Riverside, Riverside, California 92521, USA.
authors.forename: Alexander A
authors.initials: AA
authors.lastname: Balandin