Evaluation of femtosecond laser-scribed Cu(In,Ga)Se2 solar cells using scanning spreading resistance microscopy

The effect of laser-induced heat on Cu(In,Ga)Se2 solar cells was evaluated by scanning spreading resistance microscopy (SSRM) to improve the laser scribing (LS) quality. Two types of LS were examined for electrical isolation; that using transparent conductive oxide (TCO) lift-off resulted in a higher conversion efficiency of 17.4% and shunt resistance of 5 × 103 Ω·cm2. SSRM images confirmed the absence of shunt paths between the laser-induced low-resistance layer at the trench bottom and the top TCO layer, which resulted in the high shunt resistance. Ultrashort-pulse LS would be a promising tool for reducing the dead area and increasing the throughput by high-speed scribing.