Electrical spectroscopy methods for the characterization of defects in thin-film compound solar cells

The electronic activity of defects and their impact on the efficiency of Cu(In,Ga)Se-2 and CdTe solar cells is a subject of continuing interest and dispute in the photovoltaic community. However, after many years of research, the conclusions are far from satisfying yet. Here, the electrical defect spectroscopy results for Cu(In,Ga)Se-2 and CdTe absorbers and devices are discussed with focus on findings that have been confirmed on many samples but still do not have a well-grounded interpretation. Charged grain boundaries are proposed as a possible source of some signatures observed in deep level spectra in both materials. Electrical nano-characterization methods combined with standard defect spectroscopy are suggested as a promising solution for unraveling the role and origin of dominating defects for solar cells efficiency. Published under an exclusive license by AIP Publishing.

Automated summary

The electronic activity of defects and their impact on solar cell efficiency in Cu(In,Ga)Se-2 and CdTe materials is still a topic of interest and debate. This study discusses the results of electrical defect spectroscopy in these materials and proposes charged grain boundaries as a possible source for observed signatures in deep level spectra. It suggests using electrical nano-characterization methods combined with standard defect spectroscopy to unravel the role and origin of dominating defects.