Device gallium_nitride PatternedSapphireSubstrat Pattern EPFL Yeditepe_University HydroGel Transparent temp_control Vinylpyridine NTU Gallium_Arsenide dichalcogenide ScanningIon-ConductanceMicroscopy Piranha OpticalElement LMF Conducting ScratchMode Sic NusEce Electical&Electronics polyvinyl acetate Strontium electrospinning PiezoelectricForceMicroscopy GaP Multiferroic_materials PVA Metal sputter KPFM LeakageCurrent pinpoint mode Ito