P414
Control of Molecular Orientations and Optical Properties of Oligosilane Thin Films
on Uniaxially Oriented Polysilane Films
Yuji Yoshida, Yoshirou Ichino, Tetsuo Yatabe, Nobutaka Tanigaki,
Masaki Shimomura, Kiyoshi Yase, Nobutsugu Minami, Akira Kaito,
Yoshikazu Tanabe
NIMC
Polysilanes and oligosilanes, silicon-based one-dimensional semiconductors with extended sigma-conjugated
chains, are attracting much attention because of their unique optical and electrical properties. In addition,
their UV-lithographic processability can be used for the fine patterning of electrical circuit etc.
In this study, uniaxially oriented polysilane films prepared by the friction transfer method were used
as substrates for the vacuum deposition of oligosilane films. By the measurements of X-ray diffraction,
grazing incidence X-ray diffraction, and AFM, we found that oligosilanes grew epitaxially with their
molecular axis aligning with that of underlying polysilane films. On the other hand, when polysilane
substrates were irradiated by UV light prior to the deposition, oligosilanes aligned normal to the substrates
with a small tilt angle. It is shown that the photochemical decomposition of polysilanes leading
to the disappearance of the epitaxy is involved in this effect. These results have demonstrated
a possibility of lithographic control of the orientation of molecular thin films.
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