Structural and Optical Characterization of Bi-doped CuInS_2 Thin Films Grown by Vacuum Evaporation Method

摘要

Structural, electrical and optical properties of Bi-doped CuInS_2 thin films grown by a single source thermal evaporation method were studied. The films were annealed from 100 to 500 °C in air after the evaporation. The X-ray diffraction spectra indicated that polycrystalline CuInS_2 films by Bi doping were successfully obtained by annealing above 200 °C. This temperature was lower than that of the non-doped CuInS_2 films. Furthermore, ir was found that the Bi-doped CuIns_2 films became close to stoichiometry in comparison with the non-doped CuInS_2 films. The non-doped and Bi-doped samples annealed at 400°C had bandgap energy of 1.46～1.49 eV. The resistivities and the carrier concentrations of the films annealed at 400 °C were from 0.1 to 0.5 Ωcm and from 3 x 10~(18) to 3 x 10~(19) cm~(-3), respectively, at room temperature.