Scribing of thin films with picosecond laser pulses for cigs solar cells

Abstract

Laser scribing is an important step to preserve high efficiency of thin-film photovoltaic devices over large areas by production of integral interconnects. The results on picosecond laser application in the CuInxGa(1-x)Se2 (CIGS) solar cell scribing with different wavelengths and beam profiles are presented. Both, the wavelength and beam profile are of essential importance for the selectivity of the ablation process and for its efficiency. The complex absorber layer of copper-indium-gallium diselenide is a thermo-sensitive material, and laser processing might provoke undesirable modification photo-electrical properties of the material. Therefore, the scanning electron microscopy, electron-dispersion spectrometry and micro-Raman have been used to evaluate the processing results to show benefits of the used picosecond lasers in selective scribing on this type of photovoltaics structures. Ultra-short pulses ensured high energy input rate into absorbing material permitting peeling of the layers with no influence on the remaining material. Use of high repetition rate lasers with picosecond pulse duration offers new possibilities for high quality and efficiency patterning of advanced materials for photovoltaics.