Electric, thermoelectrical and photoelectric properties of CuGaxIn1−xSe2 thin films

The electrical conductivity σ, Hall effect R_H, and thermoelectric power Q of CuGa_0.25In_0.75Se₂ thin films with different growth conditions have been measured at temperature 300-520 K. These properties were also measured at room temperature for different composition of CuGa_xIn_1−xSe₂ (0.75≥x≥0) deposited at the same evaporation conditions. All investigated films are p-type over the whole temperature range. Electrical conduction was studied in order to establish its mechanism.The room temperature photoelectric response of those films were measured as a function of wavelength (2.5≥λ≥0.3) μm. It is found that the energy gap values follow a second order equation in x giving a downward bowing parameter of about 0.31 eV.