Dresden 2009 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 5: Photovoltaic
HL 5.4: Talk
Monday, March 23, 2009, 11:00–11:15, POT 151
Spectral Response of CuIn1−xGaxSe2 Heterodiodes Operated at Constant VOC and Constant ISC Compared with Traditionally Recorded Spectral Quantum Yield — •Sven Burdorf, Rudolf Brüggemann, and Gottfried Heinrich Bauer — Institute of Physics, Carl von Ossietzky University Oldenburg D-26111 Oldenburg, F.R. Germany
Traditional spectral response experiments in solar cells, such as quantum yields show the dependence of the excess carrier contribution and respective recombination on the depth of the device in terms of the profile of the optical generation. However, this depth information is masked by the condition of current continuity that is met by contributions of minority as well as majority carriers across the entire depth of the device and commonly the information on local properties is not reflected straightforwardly. In our approach - analogously to the concept of the constant photocurrent method (CPM) - we have adjusted either constant VOC (c-Voc) or ISC (c-Isc) by recording the spectral photon fluxes necessary for these conditions. In particular in Voc operation excess carriers recombine exclusively within the device and thus the signal is more sensitive against recombination. Our results of the c-Voc and c-Isc experiments for CIGSe-heterodiodes show significant differences particularly in the short-wavelength regimes. The comparison of experimental results with numerical modeling shows that this difference is growing larger with increasing interface recombination.