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Extracting Metal and Edge Recombination Parameters which are Compatible with Multi-Dimensional Cell Simulations
P. Saint-Cast, D. Herrmann, P. Baliozian, H. Stolzenburg, H. Höffler, A. Fell
Photoluminescence, Recombination, Metal, Edge Recombination, Analytical Model
Silicon Materials and Cells
Subtopic: Characterisation & Simulation of Si Cells
Event: 36th European Photovoltaic Solar Energy Conference and Exhibition
Session: 2DO.6.2
275 - 279
ISBN: 3-936338-60-4
Paper DOI: 10.4229/EUPVSEC20192019-2DO.6.2
0,00 EUR
Document(s): paper, presentation


In this work, an analytical model is presented that reproduces lateral changes in pn-junction voltage as a result of recombination at linear shaped defect. The model takes into account the majority charge carrier transport in the emitter and in the base as induced by a metal finger, an edge or any linear region with a high local recombination rate. It predicts the pn-junction voltage as a function of distance to the perturbation in one dimension. A comparison of the model with numerical device simulations using Quokka3 shows low deviation for the local voltage under the finger (< 2 mV) and at the edge (< 5 mV). The presented method to interpret the photoluminescence image of a wafer with a metal front grid is based on Fourier analysis. For each saturation current density at the metal, we can associate a predicted Fourier peak set obtained from the model. The saturation current density at the metal finger is obtained when the peaks of the photoluminescence image and the model correspond best. The model is also applied to the interpretation of photoluminescence images in the aim of evaluating the local saturation current density at the edge. In this case, photoluminescence images of the wafer edges are carried out at different illumination intensities. The pn-junction voltage profile towards the edge is calculated from the photoluminescence image of the wafer. For each illumination intensity, the saturation current density at the edge is obtained by adjusting the parameter of the model to the photoluminescence image. Finally, we obtain the saturation current density at the edge as a function of the carrier injection.