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(a) SEM image of VO2 two terminal device used in switching experiment. (b) Equivalent circuit model of pulsed IV experimental setup.
(a) Triangular VSupply pulse and corresponding potential drop VLoad across a 3.3 kΩ load resistor. (b) Rise and fall times for various load resistor extrapolated to extract VO2 switching times. Equivalent circuit model in Figure 1(b) was used for H-spice switching simulation of the (d) voltage drop across the DUT (VDUT), (e) current flowing through the circuit (IDUT), and (f) voltage drop across the 3.3 K load resistor (VLoad) compared with the experimental data from (a).
(a) Cole-Cole plot from impedance spectroscopy obtained from a 10 nm thin and 1 μm long VO2 channel by applying a 500 mV AC small signal (100 Hz–10 MHz). Experimental plot, which was modelled as an equivalent R-CCPE network , shows depressed nature of the plot. (b) The impedance data from (a) represented using Z″( = Imag(Z)) v/s frequency and M″ ( ) v/s frequency plots.
(a) Cole-Cole plots from impedance spectroscopy obtained from devices with VO2 channel lengths varying from 0.5 μm to 10μm (width kept constant at 2 μm). (b) Extracted R and C values from the IS data in (a). (c) HRTEM cross-sectional image of epitaxially grown crystalline VO2 film (10 nm) on TiO2 substrate. (d) tRC plotted for various channel lengths.
(a) Temperature dependent impedance spectroscopy where the insulating VO2 is modelled as an equivalent R-CCPE network. (b) Post IMT impedance spectroscopy at 44 °C of metallic VO2 represented as a R-L model. (c) Extracted Req and normalized Ceq values from IS as a function of temperature. (d) Schematic showing evolution of R-C networks and phase coexistence in VO2 bulk to R-L networks across the IMT.
(a) Total conductivity as a function of frequency (75 KHz–3.5 MHz) for various temperatures (3 °C–40 °C) with VO2 in the insulating state. (b) Relaxation times extracted from the AC conductivity plot in (a) as a as a function of temperature.
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