Regensburg 2013 – scientific programme
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O: Fachverband Oberflächenphysik
O 84: Photovoltaics (jointly with CPP, DS and HL)
O 84.1: Talk
Friday, March 15, 2013, 09:15–09:30, H2
Simulation of TRPL on thin film solar cells — •Matthias Maiberg, Maria Gaudig, and Roland Scheer — Institute of Physics, Martin-Luther-University Halle-Wittenberg, Von-Danckelmann-Platz 3, 06406 Halle, Germany
In the recent years time-resolved photoluminescence (short: TRPL) on semiconductor devices has been established as a non-destructive, non-invasive, contactless characterization method. The decay of the signal has not been fully understood yet. Therefore we studied TRPL on semiconductor layers and thin film solar cells by simulation with Synopsys TCAD. At first we investigated the influence of excitation, diffusion, photon recycling, bulk-defects and defects at the contacts, as well as space charge and potential fluctuations on the PL-decay separately by quasi-onedimensional simulations of absorber layers and thin film solar cells. We also studied the influence of grain boundaries, since materials like Cu(In,Ga)Se2 and Cu2ZnSnSe4 are in general polycrystalline. We show, that the samples can be characterized by excitation dependent measurements in the open circuit case. We can explain some effects found in photoluminescence experiments, like a decrease of the lifetime with an increasing excitation, a maximum lifetime due to saturated bulk-defects, and a lifetime of more than 10µ s in case of charge separation due to the electric field in the space charge region.