Effects of iodine doping on electrical and optical properties of ternary Si:C:H films prepared by evaporation of organopolysilane

Abstract

The effects of iodine doping on the electrical and optical properties of ternary Si:C:H films prepared by the evaporation of organopolysilane have been examined. The evaporated films contain a large number of one-dimensional silicon backbones, and their optical absorption spectra show a sharp peak at 300 nm. The 300 nm absorption peak shows a red shift due to the iodine doping, which clearly indicates the change in the electronic structure of the material. The vibrational frequencies for the Si(CH3)2 groups are also changed by the doping, and some new peaks are observed in the infrared absorption spectra. By changing the doping time, the conductivity can be controlled over the range from 10-14 to 10-9 S cm-1. The doping mechanism is finally discussed on the basis of the obtained experimental data.