Investigation of CIS/CIGS and CdTe solar cells scribing with high-power fibre short pulse lasers

Abstract

We present here some of the last results of the EUROPEAN project ALPINE. We present both the development of an adjustable fibre laser pulse source and scribing results on CdTe and CIGS solar cells. The scribing tests were performed at three different pulse durations: 400 fs, 8 ps and 250 ps. The results obtained with 250 ps are already very promising for P3 steps in both CdTe and CIGS solar cells. In both cases the results were validated electrically.In the case of P3 scribing for CIGS solar cells, shunt resistances as high as 125 kΩ.cm were obtained. Isolation resistances were higher than 1 MΩ.cm. The processing speed was 2 m/s.

Optimization of pulsed fiber laser scribing for CdTe and CIGS solar cells

“…The main reason of the better scribing quality may be due to the value of the M2 parameter, the laser beam quality factor, that is about 1.1 for the fiber laser, and 1.6 for the solid state laser. Further improvements can be achieved by employing a fiber laser working with very short pulses [5]. Additional tests of various P1 grooves though a SEM analysis have shown that the Heat Affected Zone (HAZ) at the edges of the scribing is very narrow and with no material re-deposition in the groove during the ablation process, as shown in Fig.…”

“…The Alpine project aims to achieve excellent scribing patterning on CdTe and CIGS modules by means of high performance fiber lasers. Several works on lasers scribing solutions for solar cells exist [4,5] but generally face some limitations [6] that are related to long pulses duration. This is a general concern today in solar cells industry to have a high speed and precision process without important induced damages.…”