Numerical simulation of CIGS solar cell for defect modeling

Defect models are investigated for graded bandgap structured copper indium gallium selenide (CIGS) cells, which are fabricated using a solution based process. We have numerically simulated the cell performances for Gaussian and tail defects in mid gap and forbidden bands of each layer of the CIGS solar cell by using a computer-aided design program. By comparing the simulation results with the measurements, it is found that the donor-type defects in the valence band of CIGS absorber need to be reduced to further improve the CIGS cells. Based on this result, high performance CIGS cells can be developed in the future.