Hole Tin disulfide GalliumPhosphide WS2 Alloy Pipette Scanning_Thermal_Microscopy ForceVolume PinPointMode C60H122 Polyethylene Tungsten_disulfide TappingMode ChemicalCompound TipBiasMode Fiber PetruPoni_Institute DIWafer Bismuth Metal PS_LDPE HBN GranadaUniv SiliconOxide Nickel kelvin probe force microscopy Copper molecular_beam AdhesionForce atomic_steps AM_KPFM MESA structure phase_change DeflectionOptics dichalcogenide