Evaluating the electrical properties of silicon wafer solar cells using hyperspectral imaging of luminescence

A line-imaging spectrometer is used to collect the spectrum of electroluminescence at each point of a multicrystalline silicon wafer solar cell. Characterization of the diffusion lengths of minority charge carriers is developed using a specific feature of the luminescence spectral signature. It is shown that various material and device parameters affecting the luminescence spectral signature may be determined independently. Diffusion length images derived from the proposed hyperspectral method are assessed against diffusion lengths obtained by light beam induced current measurements. Using hyperspectral imaging, diffusion lengths of minority charge carriers in a silicon wafer solar cell can be determined.