PvdfBead DomainSwitching Vanadate Fendb Non-ContactMode Defect GaN temperature_control 2-vinylpyridine self_healing Switching EFM ScanningKelvinProbeMicroscopy Reduction LightEmission kelvin probe force microscopy ConductingPolymer Chungnam_National_University CastIron AnodizedAluminumOxide Polyvinylidene Pzt contact Modulus organic_polymer FM_SKPM Fujian LateralForce NCM\ Array HanyangUniv BaTiO3 Roughness CHRYSALIS_INC TransitionMetal