SKM 2023 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 45: Functional semiconductors for renewable energy solutions II

HL 45.5: Vortrag

Donnerstag, 30. März 2023, 16:30–16:45, POT 6

beneficial impact of KF post-deposition treatment on optical diode factor and non-radiative recombination of CIGSe absorbers — •Sevan Gharabeiki, Mohit Sood, Valentina Serrano Escalante, Taowen Wang, and Susanne Siebentritt — Department of Physics and Materials Science, University of Luxembourg, 4422 Belvaux, Luxembourg

The efficiency of the solar cells depends on the open circuit voltage (VOC), short circuit current (JSC), and fill factor (FF) which in turn depends on the diode factor. The quasi-Fermi level splitting (QFLS) is the upper limit for VOC and the optical diode factor (ODF) is the lower limit of the diode factor. It has been long known that post-deposition treatment (PDT) with heavy alkalis has a beneficial impact on CIGSe solar cells. An increase in the hole concentration, decrease in non-radiative recombination, and surface passivation have been reported by many studies. We present the effect of the KF PDT on the CIGSe absorbers with different deposition temperature. Our study shows that the KF PDT increases the (QFLS) and decreases non-radiative recombination for the samples deposited on soda lime glass with high deposition temperature. For the samples with low deposition temperature, the improvement in QFLS is mainly due to an increase in doping level. A combination of QFLS, lifetime and capacitive-voltage measurements were conducted to separate the doping effect from the non-radiative recombination effect. We propose that high concentration of Na is required to get the full effect of KF PDT, i.e. increase in the doping and decrease in the non-radiative recombination.