Figure 4. Simulated transport properties determined by the diffusion of intercalated ions.

(a) Schematic of the ion intercalation at the interface between air and VO₂, resulting from chemical kinetics and the diffusion area (gray region), found using Fick’s diffusion model under an electric field (E(x)) derived by Poisson’s equation. The simulated channel resistance was calculated using the parallel resistor model for the intercalated (ρ_IH) and non-intercalated (ρ₀) resistivities and by taking each width into consideration, as shown on the right side in (a). (b) Time dependence of the simulated R/R₀ with a variety of V_G values for 500 nm wide VO₂ channels. (c,d) Spatial- and time-evolution maps of the hydrogen ion concentration at (d) V_G = 27 V and (e) 38 V. x = 0 indicates the interface.