Structure and orientation of vacuum-evaporated poly(di-methyl silane) film

Abstract

We have succeeded in obtaining the primitive translation vectors of the sub-cell of poly(di-methyl silane) [Si(CH 3) 2] n crystal. The crystal structure of poly(di-methyl silane) has been clarified by comparing the experimental X-ray diffraction pattern with that of theoretical pattern. The crystal has a monoclinic unit cell (sub-cell) with a =0.745 nm, b=0.724 nm, c=0.389 nm and γ=67.1°. Although poly(di-methyl silane) is the most fundamental polysilane, it is not solved in organic solvents at room temperature. Therefore, the poly(di-methyl silane) thin film has been prepared by a vacuum evaporation technique. In this paper, poly(di-methyl silane) thin films are prepared using new vacuum evaporation system, and the orientation of poly(di-methyl silane) chain has been examined as a function of vacuum pressure as well as substrate temperature during the evaporation. As a result, it is found that the orientation of poly(di-methyl silane) chain is strongly affected not only by the pressure but also by the substrate temperature during the deposition.