Analyzing the spectral luminescence emission of silicon solar cells and wafers

We present an analytical expression for modelling electroluminescence (EL) as well as photoluminescence (PL) data of samples with any combination of planar and arbitrary rough surfaces. The model also accounts for free carrier absorption in highly doped regions of the sample. It is experimentally confirmed by comparison to measured EL and PL spectra of solar cells and wafers featuring different surface geometries. Significant differences in the absorption coefficient data available from literature, which enters the model as tabulated data, are revealed. Using our model, the absorption data by Daub yields the best agreement to the measured luminescence spectra. Moreover, we present a method to determine the rear surface reflectance of samples from the peak wavelength of luminescence spectra.