Electrical switching and Mott transition in VO2

Abstract

In this paper the problem of the Mott metal-insulator transition in vanadiumdioxide driven by an external electric field is considered. Delay time (td)measurements have shown that the experimental value of td is almost threeorders of magnitude lower than the theoretical value, calculated in a simpleelectrothermal model. This suggests that under non-equilibrium conditions (inhigh electric fields) electron correlation effects contribute to the developmentof the insulator to metal transition. The extra-carrier injection from Si intoVO2 was carried out in the structures Si-SiO2-VO2 on p-type siliconwith ρ = 0.1 Ω cm and a SiO2 thickness 70 nm. It has been shown thatthe metal-insulator transition in VO2 can be initiated by injection, i.e. by the increase of the electron density. The value of the critical density wasfound to be of the order of the electron density in VO2 in the semiconductingphase, approximately 1018-1019 cm-3. This confirms thatthe metal-insulator transition in VO2 is the purely electronic Mott-Hubbardtransition.