Extended Data Fig. 2: Structural and functional characterization of hBN synthesized at 250 °C.

(a) AFM image of the hBN surface over a 2 × 2 μm area, revealing an morphology with RMS roughness = 0.56 ± 0.03 nm. (b) Raman spectrum of hBN, showing the characteristic E2g vibrational mode at ~1362 cm−1, confirming hBN formation. (c) Cross-sectional TEM image of hBN, showcasing its atomic-scale layered structure and nanocrystallinity. (d) I–V curves under white LED illumination (red curve) and dark conditions (black curve), demonstrating pronounced hysteresis and nonvolatile memristive switching behavior.