SKKU Vacuum Lattice TappingMode Nanopattern piezoelectric force microscopy Boundary Transparent FFM FM_KPFM NTU Techcomp ReflexLens PFM Sio2 VerticalPFM Hexacontane Non-ContactMode TPU Al2O3 Ucl phase_change ContactModeDot Iron NUSNNI Platinum single_layer DNA Beads IMT_Bucharest AEAPDES SiliconCrystal Granada Wafer LateralForceMicroscopy