Heating effect on C60 films during microfabrication: structure and electrical properties Original Research Article

Thin films of C60 fullerene were prepared by vacuum evaporation on cold substrates of thermally oxidized and bare silicon wafers. The effect of thermal annealing on C60 films was investigated by means of Raman, atomic force microscopy and X-ray diffraction. It was found that the densification of C60 films occurred at low temperature range whereas the change of C60 structure to microcrystalline graphite occurred when high temperature annealing. The C60 films annealed at 100 °C have the highest packing density, low surface roughness, high degree of crystallinity and stable ohmic contacts. These results clearly indicated that the electronic properties of C60 can be improved by heating in low temperature range without affecting the heat treatments in the microfabrication.