Fig. 2: Characteristics of epitaxial VO₂ memristor.

a Schematic diagram of the memristive device, which is a planar structure. b Scanning electron microscopy (SEM) image of the epitaxial VO₂ memristor. c Zoom-in views of the channel locations in SEM. d Cross-sectional transmission electron microscopy (TEM) image of the epitaxial VO₂ memristor. e A closer view of the device in TEM. f Zoom-in views of the epitaxial VO₂ region. g The diffraction pattern extracted by fast Fourier transformation of (f). h Current-voltage characteristics of the device repeated for 1000 cycles. i Distributions of high and low resistance states of the epitaxial VO₂ device in 1000 repeated cycles. j Cumulative plots of positive threshold voltage (V_{th_pos}), positive holding voltage (V_{hold_pos}), negative threshold voltage (V_{th_neg}), and negative holding voltage (V_{hold_neg}).