Dresden 2006 – scientific programme

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HL: Halbleiterphysik

HL 32: Photovoltaic

HL 32.17: Talk

Wednesday, March 29, 2006, 18:45–19:00, BEY 118

Analysis of Charge Carrier Dynamics in Cu(In,Ga)Se₂ from Sub-Micron Resolved Luminesence and Photocurrent Studies — •Levent Gütay and Gottfried H. Bauer — Institute of Physics, Carl von Ossietzky University, D-26111 Oldenburg, Germany

We have analysed thin film Cu(In,Ga)Se₂ solar cells by sub-micron resolved photoluminescence (PL) and light induced photocurrents. Respective scans show significant lateral variations of PL-yield (Y_PL) in the few micron scale, which correspond to locally varying quality of the photoexcited state of the absorber. PL-scans performed, both, under open and short circuit conditions (oc and sc) show differences of lateral signal profiles reflecting local variations of excess charges and consequently signalizing the influence of differences in carrier dynamics between these two modes of operation. Additionally simultaneously recorded local photocurrents (I_sc) exhibit a substantial local anti-correlation with PL. Since locally resolved PL quantitatively reflects local excess carrier densities and I_sc their respective product with their speed of extraction (perpendicular to the surface of the junction) we get experimental access to this magnitude and observe e.g. fast extraction of photoexcited carriers at the edges of the regimes with high Y_PL and comparatively low one in their respective centers.