MoirePattern kelvin probe force microscopy IIT-chennai BiFeO3 2-vinylpyridine Potential Terrace CVD flakes Celebration NanoLithography self_assembly DataStorage Change C60H122 Dopped CNT Multiferroic_materials Hexylthiophene Adhesion Etch Fet StainlessSteel STO Lattice heterojunctions non_contact SurfaceChange Vanadate UnivCollegeLondon SKPM domain_switching ContactModeDots Composition OpticalModulator