Tin sulphide films deposited by plasma-enhanced chemical vapour deposition

Tin sulphide thin films have been prepared by the plasma enhanced chemical vapour deposition technique, using H2S and SnCl4 as source materials. For given values of the deposition pressure, relative gas flow rates and deposition time, the plasma power density and the substrate temperature were varied in the ranges from 0.023 to 0.080 W cm(-2) and from 100 to 300 degrees C respectively. The deposited films show an orthorhombic crystalline structure for the entire plasma power range and for substrates temperatures higher than 150 degrees C. From the studied optical properties, considering that this is an indirect energy bandgap material, the energy bandgap is calculated to have a value of 1.16 eV; the phonon involved in the electronic transition has an energy of 0.18 eV. From the measurements of electrical conductivity as a function of temperature an activation energy of 0.3 eV was determined with a p-type electrical conductivity.