We present a study of the degradation of thin-film CIGS material in the vicinity of P2 phase-transformation type of laser scribes. They comprised optical microscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy, photoluminescence and Raman spectroscopy. While the optical and electron microscopy measurements have shown a clear change of the morphological properties of CIGS including removal, melting and dislocation of material from the area scribed by the laser, the X-ray analysis revealed an accumulation of O, Zn, Ga, and Cu elements in the melted phase and an evaporation of more volatile In atoms from the region of visually changed CIGS. At the same time Raman and photoluminescence measurements have shown substantial alteration of semiconductor material properties, i.e. of the crystallinity and the bandgap energy even far beyond of this region. More precisely, the amplitudes of the A_1 and B_2, E Raman peaks were found to increase continuously with increasing distance from the P2 scribes, reaching the distances of approximately three times the 3o~ diameter of the beam. A similar tendency was also observed for photoluminescence signals, that additionally revealed a systematic shift of the bandgap energy in CIGS as estimated from the maximum of the emission spectrum. Our results indicate that the phase-transformation scribing generates changes in thin-film CIGS material far beyond the heat affected zone. As such they can help to decide on optimal spacing between P1-P3 scribes and thus reduce a "dead area" of thin-film CIGS solar cells.
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