Fig. 4

Comparative SFM study for hexagonal silicon carbide (6H-SiC) sample by using silicon or PEGDA tip attached quartz tuning forks with similar tip radii. SEM images of a a commercial silicon tip and b a PEGDA tip attached quartz tuning forks. Left and right images are taken at low and high magnification, respectively. QTF’s resonance frequency and amplitude shift for the approach and retract cycle over a 6H-SiC sample with c the silicon tip attached and d PEGDA tip attached QTFs. e Dynamic mode topography, f linescans along the black dotted lines, and g histograms of the transition slope for the 3rd step (between the 3rd and 4th atomic layers) of the 6H-SiC. The first and second rows are for the silicon tip attached and PEGDA tip attached QTFs, respectively