Fujian tip_bias_mode #Materials Memory TiO2 GaN University_of_Regensburg Solution self-assembly DNAProtein Growth FFM Wang CalciumHydroxyapatite thermal_property Calcium PvdfFilm SurfaceChange Oxide MechanicalProperties layers UnivMaryland dichalcogenide Gold PVAP3HT chemical_compound Holes Typhimurium MetalCompound kelvin probe force microscopy MagneticForceMicroscopy HfO2 fluoroaalkane Semiconductor Beads