Electrical switching and Mott transition in VO₂

In this paper the problem of the Mott metal-insulator transition in vanadium dioxide driven by an external electric field is considered. Delay time (td) measurements have shown that the experimental value of td is almost three orders of magnitude lower than the theoretical value, calculated in a simple electrothermal model. This suggests that under non-equilibrium conditions (in high electric fields) electron correlation effects contribute to the development of the insulator to metal transition. The extra-carrier injection from Si into VO2 was carried out in the structures Si-SiO2-VO2 on p-type silicon with ρ = 0.1 Ω cm and a SiO2 thickness 70 nm. It has been shown that the 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 was found to be of the order of the electron density in VO2 in the semiconducting phase, approximately 1018-1019 cm-3. This confirms that the metal-insulator transition in VO2 is the purely electronic Mott-Hubbard transition.