Quality control and characterization of Cu(In,Ga)Se2-based thin-film solar cells by surface photovoltage spectroscopy

Surface photovoltage phenomena: theory, experiment, and applications

“…The upper curve in Fig. 46 [404] features the usual SPV response obtained from pCu(In,Ga)Se 2 polycrystalline ®lms. It shows a positive CPD change near the Cu(In,Ga)Se 2 bandgap energy, as expected.…”

“…46. SPV spectra of Cu(In,Ga)Se 2 polycrystalline ®lms: a typical response and an irregular response (after Kronik et al [404]). …”

“…Recently, Kronik et al have used SPS measurements for quality control of ZnO/CdS/CIGS-based solar cells [404]. In this study, the contactless nature of the measurement made it possible to eliminate defective structures after the deposition of each of the three semiconducting layers.…”

“…85(a) shows that the SPV spectrum of the Na-poor sample is qualitatively different then the other SPV spectra: it features a distinct decrease of the SPV signal immediately after its initial onset, whereas the other spectra continue to increase with increasing photon energy, until $1.7 eV (where the SPV reduction is attributed to a surface state lying at the external CdS surface). The Quantum ef®ciency spectra of a ZnO/CdS/ CIGS solar cell, based on a Na-poor and a Na-rich CIGS layer (after Kronik et al [404]. Quantum ef®ciency data taken from Rau et al [765]).…”

Effects of Sodium on Polycrystalline Cu(In,Ga)Se2 and Its Solar Cell Performance

“…[43] ii) For ZnO/CIGS structures (with no CdS buffer) Na incorporation actually decreasesÐrather than increasesÐV oc . [46] A full explanation of this observation requires further study. However, it serves as a reminder that the beneficial, Na-related, effects on the CIGS absorber detailed above may at times be eclipsed by adverse Na effects on the window layer and/or the CIGS/window interface.…”