Determination of effective masses of electron an evolution of the lattice parameters in no stoichiometric Cu(In_1-x,Ga_x)Se₂ chalcopyrite thin film solar cell

In this paper, a study was carried out on the evolution of the effective mass of the electron and the effective mass of the crystal parameters in solar cells basedon non-stoechiometric absorbers Cu (In_1-xGa_x) Se₂. Usually the stoechiometry is defined for this type of cells in relation to the ratio for x between 0.1 and 0.9 with . For this work we have defined the stoechiometry according to the ratio for x values between 0.1 and 0.9. We have noted that the ratio increases with x and the energy gap Eg of the material, and that mealso increases with this ratio. The lattice parameters increase with the ratio and with the gap energy Eg. In the end, two relations linking the crystal parameters and this ratio were determined