Figure 6. Pixel-wise comparison of the current and lateral force images. Current, lateral force, and topography images obtained using ( a ) Probe A and ( b ) Probe B during trace scans. F n is the normal force applied to the ZnO nanorods by the AFM tip. Magnified images of the small areas marked by boxes are provided, with corresponding scatter plots on the right. ( c ) Line profiles of the magnified current and lateral force images in ( a ) and ( b ). ( d ) Schematics of three distinct current generation mechanisms: contact potential, triboelectric effect, and simultaneous piezoelectric and triboelectric effects 34