The field-effect in vanadium dioxide and the metal-insulator transition*

VO$_2$ and its metal-insulator transition are currently of interest to enhance understanding of metal-insulator transitions and for investigating possible applications in nanoelectronic devices. Inducing the metal-insulator transition by means of an electric field, instead of by changing the temperature, could entail a major enhancement of present-day nano-electronics. Both the field induced metal-insulator transition and the regular semiconductor field-effect are investigated in this work using monocrystalline VO$_2$ field-effect structures. The field dependent VO$_2$ conduction characteristics across the metal-insulator transition are elucidated. The relation of these VO$_2$ characteristics with the VO$_2$-insulator interface is clarified by means of admittance analysis.