SAM non_contact MechanicalProperties Graphite Flake Wafer sputter VerticalPFM InsulatorFilm contact FailureAnlaysis Chloroform Hysteresys FrictionalForce TPU Korea gallium_nitride Polymer STO Pyroelectric Gallium fifber hetero_structure SICM Piezo LithiumNiobate SetpointMode lithography PatternedSapphireSubstrat ScanningTunnelingMicroscopy Plug Gallium_Arsenide Pvdf Hair Polarization