Effect of [Ga]/[In+Ga] Atomic Ratio on Electric Parameters of Cu(In,Ga)Se 2 Thin Film Solar Cells (original) (raw)

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. Keywords— CIGS solar cells, [Ga]/[In+Ga], electric parameters, external quantum efficiency, SCAPS-1D. I. I ntro d uct io n Nowadays, the Photovoltaic technology based on CIGS has considerable growth potential in improving performance and lower production costs. The best way to understand the working mechanisms of these devices such as currents transport, electron-hole generation and recombination phenomena is the construction of numerical models for simulation. For this we used a numerical simulation software called SCAPS-1D (Solar Cell Capacitance Simulator one dimension), developed in the laboratory ELIS (Electronics and Information Systems) from the University of Gent, Belgium [1]. This allows elucidating the processes which limit the cell performance and give an optimal design of the structures at the base of these devices. In this article, we study the influence of [Ga]/[In + Ga] atomic ratio on electrical parameters of CIGS solar cell. Different cells with varying atomic ratios are used. The parameters studied are the current-voltage characteristic (J/V), the open circuit voltage (Voc), the short-circuitcurrent density (Jsc), the fill factor (FF), the conversion efficiencies (η), the capacitance-voltage characteristic, the conductance-voltage characteristic and the quantum efficiency (QE). This work allows us to take note of the atomic ratio which would lead to an optimal CIGS cell.