SurfaceOxidation IVSpectroscopy Sulfur Formamidinium_lead_iodide India Worcester_Polytechnic_Institute Deposition Optic temp STM self-assembly Graphene Heat Mechanical LiftHeight Jason AtomicLayer Spain Conductivity Vanadate amplitude_modulation LiquidCell Christmas Nanostructure Au111 PolycrystallineFerroelectricBCZT Fet Metal-organicComplex PDMS HighResolution Cobalt TappingMode FM_KPFM HexagonalBoronNitride temperature controller AFM