Ucl ConductiveAFM amplitude_modulation SiWafer FM-KPFM biocompatible Global_Comm PtfeMembrane BismuthVanadate OpticalWaveguides Electrode PolyvinylAcetate CaMnO3 solar_cell TappingMode CopperFoil University_of_Regensburg molecule aluminum_nitride Temperature Epoxy HiVacuum NTU PDMS ScanningKelvinProbeMicroscopy Korea Ito SiliconCrystal Anneal PvdfFilm Co/Cr/Pt Foil Film vertical_PFM IRDetector