Picosecond Laser Induced Selective Removal of Functional Layers on CIGS Thin Film Solar Cells

AbstractPicosecond laser pulses provide a controlled laser based removal used for micro structuring of functional layers, such as copper-indium-gallium-diselenide (CIGS), due to a reduced thermal penetration depth, compared to nanosecond pulses. It is shown that with 7 ps pulse width at a wavelength of 532nm the P2 and P3 processing of thin film solar cells on glass substrates and flexible polyimide substrates is possible. A Gaussian as well as a top-hat energy distribution were utilized for the experiments. With adjusted laser and processing parameters they allow for the fabrication of precise isolation trenches (width << 100μm), without damaging the adjacent layers due to mechanical stress or thermal stress