UnivMaryland kelvin probe force microscopy dielectric_trench Materials Yeditepe_University SiliconOxide Topography Cancer Fiber Force-distance Wildtype MBE LightEmiting SRAM exfoliate GaN ConductingPolymer Co/Cr/Pt Hexatriacontane silicon_oxide LFM AtomicSteps Ceramics BismuthFerrite NUS InsulatorFilm CHRYSALIS_INC Workfunction CNT Protein AM-KPFM cross section SThM optoelectronics PFM