Dispersive capacitance and conductance across the phase transition boundary in metal-vanadium oxide-silicon devices

Utilizing metal-vanadium oxide (VO2)-semiconductor capacitor device structures, we have investigated the temperature- and frequency-dependent dielectric and ac conductance responses of vanadium oxide thin films that undergo metal-insulator transition (MIT). In both metallic and insulating regimes, VO2-based devices showed large tunabilities as high as similar to 95% and similar to 42%-54%, respectively. The frequency dependence of capacitance and ac conductance displays power-law behavior with respect to temperature and applied voltage over a broad range. Low-frequency dispersion in dielectric properties was also observed and their onset frequency varies across the MIT from similar to 0.5 MHz in insulating state to similar to 50 kHz in metallic state. The results are of potential relevance to utilizing functional oxides in electronic devices.