Effect of [Ga]/[In+Ga] Atomic Ratio on Electric Parameters of Cu(In, Ga)Se2 Thin Film Solar Cells

In this paper we study the influence of [Ga]/[In + Ga] atomic ratio on electric parameters of the CIGS solar cell. We conduct the simulation of a solar cell constituted of window layer (ZnO)/buffer layer (CdS)/absorber Cu(In, Ga)Se2 using the SCAPS-1D program. We vary the [Ga]/[In + Ga] atomic ratio according to the values 0.3; 0.5 and 0.7. This variation intended to study the behavior of macroscopic electrical parameters (Voc, Jsc, FF, η), characteristic J/V, conductance G/V, capacitance C/V and external quantum efficiency EQE of the cell. The results obtained show that the performance of CIGS solar cells decrease with increasing in [Ga]/[In+Ga] ratio. A conversion efficiency of about 21.54% is obtained with the cell having a ratio of 0.3. This makes it the most promising approach of our cells studied.