Electroluminescence imaging of laser induced defect formation in Cu(In, Ga)Se₂ solar cell

The combination of lasers and solar cells has potential applications in many areas. Therefore, investigating the laser induced damage and defect formation in such cells is crucial. In this study, a Cu(In, Ga)Se₂ solar cell was irradiated with a 532 nm continuous wave laser beam. The damage threshold power density with irradiation for 10 s was found to be approximately 5000 W/cm² by analyzing the light current density–voltage curves and the variation of the solar cell efficiency after laser exposure. Further, absolute electroluminescence (EL) imaging with distributed circuit modeling was used to determine the laser induced defects. By simulating the measured injection current dependent EL intensities of the defect spots, the defects created by exposure to laser power densities less than 5000 W/cm² could be mainly attributed to increased series resistance or increased transparent conductive oxide layer resistance, whereas those created by exposure to laser power densities greater than 5000 W/cm² could be mainly attributed to decreased shunt resistance.