| 초록 |
Soft building blocks such as block copolymers, colloids, liquid crystals, and supramolecules have been widely studied for bottom-up lithography. Nanostructures can be formed spontaneously based on molecular shapes and molecular interactions, so self-assembly of soft building blocks have been used for the nanopattern fabrication. To improve nanopatternings, formation of high ordered structures over large area is needed. Among soft materials, we selected supramolecules and tried to create well-ordered structures. Supramolecules have small feature size (~5 nm) and fast stabilization time (~ 30 min) to self-assembly. These merits have been useful for creating nanostructures over large area without defects. Here we used tapered shape dendrimers, which was self-assembled to the cylindrical structure by thermotropic liquid crystal properties. To obtain well-aligned structures, we used high aspect ratio (10:1) metal nano line patterns which were fabricated by secondary sputtering phenomenon. Metal line patterns with small width (~ 20 nm) acted as micro channels and cylindrical supramolecules had planar alignment within patterned regions by channel confinement effect. Small diameters (4.75 nm) of the cylindrical structure and the alignment direction were observed by AFM. Fully covered structures within few millimeters patterned regions were confirmed by POM. Our results provide unidirectional oriented thin organic films over large area directly by simple coating method and temperature control and give a potential to develop bottom-up approaches based on supramolecular structure. |
