Photochemical fabrication of three-dimensional micro- and nano-structured surfaces from a C60 monoadduct

Abstract

Exposure of Langmuir–Blodgett (LB) films of a C₆₀ adduct supported on silicon wafers to UV light leads to cross-linking of the C₆₀ moieties, which are resistant to removal by solvent exposure, whereas unexposed moieties are readily removed. This process provides a convenient and simple route for the fabrication of highly conjugated surface-attached structures, with dimensions ranging from micrometres (using masks) to a few tens of nanometres using light emitted from a scanning near-field optical microscope (SNOM). The SNOM writing velocity was found to significantly affect the lateral resolution and the height of the three-dimensional nanostructures. Increasing the writing velocity from 0.3 to 2 μm s⁻¹ resulted in a decrease in the width of the structures from 240 nm to 70 nm (corresponding to the SNOM aperture diameter), respectively, and a reduction in the height from 8 nm (the thickness of the original film) to 3 nm, respectively. This approach provides a simple, direct route to surface-bound nanometre scale assemblies of C₆₀.