title: Positive-bias gate-controlled metal-insulator transition in ultrathin VO2 channels with TiO2 gate dielectrics.
abstract: The next generation of electronics is likely to incorporate various functional materials, including those exhibiting ferroelectricity, ferromagnetism and metal-insulator transitions. Metal-insulator transitions can be controlled by electron doping, and so incorporating such a material in transistor channels will enable us to significantly modulate transistor current. However, such gate-controlled metal-insulator transitions have been challenging because of the limited number of electrons accumulated by gate dielectrics, or possible electrochemical reaction in ionic liquid gate. Here we achieve a positive-bias gate-controlled metal-insulator transition near the transition temperature. A significant number of electrons were accumulated via a high-permittivity TiO2 gate dielectric with subnanometre equivalent oxide thickness in the inverse-Schottky-gate geometry. An abrupt transition in the VO2 channel is further exploited, leading to a significant current modulation far beyond the capacitive coupling. This solid-state operation enables us to discuss the electrostatic mechanism as well as the collective nature of gate-controlled metal-insulator transitions, paving the pathway for developing functional field effect transistors.
authors.affiliation: Department of Materials Engineering, The University of Tokyo, Tokyo 113-8656, Japan.|JST-CREST, Tokyo 113-8656, Japan.
authors.forename: Takeaki
authors.initials: T
authors.lastname: Yajima
authors.affiliation: Department of Materials Engineering, The University of Tokyo, Tokyo 113-8656, Japan.|JST-CREST, Tokyo 113-8656, Japan.
authors.forename: Tomonori
authors.initials: T
authors.lastname: Nishimura
authors.affiliation: Department of Materials Engineering, The University of Tokyo, Tokyo 113-8656, Japan.|JST-CREST, Tokyo 113-8656, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Toriumi