Berlin 2015 – wissenschaftliches Programm
HL 5.2: Vortrag
Montag, 16. März 2015, 09:45–10:00, EW 202
Influence of metastable defect characteristics on the carrier collection in Cu(In,Ga)Se2 thin film solar cells — •Stephan J. Heise1, Maria S. Hammer1, Viktor Gerliz1, Jörg Ohland1, Janet Neerken1, Jan Keller2, and Ingo Riedel1 — 1Energy and Semiconductor Research Laboratory, Chair: Jürgen Parisi, Department of Physics, University of Oldenburg — 2Currently: Department of Engineering Sciences, Solid State Electronics, Uppsala Universitet
Despite the current progress of Cu(In,Ga)Se2 thin film photovoltaics, the relation between the metastable defect characteristics and key parameters of the solar cells has not yet been fully explained. In this work we discuss the correlation between metastable defect densities and short-circuit current JSC of solar cells conditioned via white-light soaking (LS) and dark air-annealing (DA), respectively. The JSC of DA-treated devices was found to decrease by 0.8 mAcm−2 upon LS treatment, which suggests a conditioning-induced change of the carrier collection. Partly, this phenomenon can be attributed to a change of the metastable net doping density. However, device simulations and cross-section EBIC measurements suggest that this explanation is not sufficient to describe the observed JSC difference. Moreover, time-resolved photoluminescence revealed a significant decrease of the decay lifetime upon LS along with an increase of the N1 defect concentration by 9.5·1014 cm−3, as evaluated from temperature dependent admittance spectra. In conclusion, we propose, that the observed JSC metastability originates from both, treatment-induced changes of the net doping concentration and defect-related transport properties.