fluorocarbon PinPointMode Vanadate Annealed Polarization SKPM chemical_compound ForceDistanceSpectroscopy phase_change AAO HydroGel SurfaceOxidation STO Tapping Pinpoint YszSubstrate molecular_beam BCZT CP-AFM Sperm BaTiO3 Ceramics Copper AIN optoelectronics Mosfet kelvin probe force microscopy high_resolution hydrocarbon KPFM BTO HACrystal BiasMode Vacuum EFM