Annealing Effect on Dark Electrical Conductivity and Photoconductivity of Ga-In-Se Thin Films

Dark-conductivity and photoconductivity properties of thermally evaporated Ga-In-Se (GIS) thin films were investigated in the temperature range of 80-430 K. All measurements were performed on as-grown and annealed GIS thin films at 300 and 400° to get information about the effect of the annealing temperature on the conductivity properties. Room temperature conductivity was obtained as 1.8 × 10^{-8} Ω^{-1} cm^{-1} for as-grown films and increased to 3.6 × 10^{-4} Ω^{-1} cm^{-1} for annealed films at 400°. Analysis of the dark-conductivity data of as-grown films revealed nearly intrinsic type of conductivity with 1.70 eV band gap energy. Temperature dependent dark conductivity curves exhibited two regions in the 260-360 and 370-430 K for both of annealed GIS films. Conductivity activation energies were found as 0.05, 0.16 and 0.05, 0.56 eV for films annealed at temperatures of 300 and 400°, respectively. The dependence of photoconductivity on illumination intensity was also studied in the range from 17 to 113 mW/cm^{2}.