Etching of CuInSe2 thin films—comparison of femtosecond and picosecond laser ablation

In this paper, the processing of the new absorber material for thin film solar cells, CuInSe2 (CIS), and the generation of trenches by femtosecond and picosecond laser etching is investigated. Threshold fluences and processing parameters for selective thin film ablation were ascertained. TEM, EDXS and Raman investigations were used to study the generation of defects in the CuInSe2 crystal lattice near to the surface due to laser processing. Femtosecond as well as picosecond laser ablation cause only little material modification of this compound semiconductor and allow high quality laser scribing for photovoltaic applications.