Structure and optical properties of ternary Si:C:H films prepared by evaporation of organo-polysilane

Ternary Si:C:H films are prepared by evaporating per-methyl-polysilane powder. The structure and optical properties of the films obtained are examined by various techniques. From infrared absorption and X-ray diffraction measurements, it is found that the film prepared at 27 degrees C contains a large number of Si backbones with an alternating trans-gauche conformation. The ultraviolet absorption spectrum shows a large peak at 300-350 nm and also supports the existence of one-dimensional Si chains. On the other hand, the film prepared at 300 degrees C contains a large number of helical backbones and shows a narrow absorption band at 300 nm. The strength of this absorption band strongly depends on measurement temperature, suggesting excitonic absorption.