A new method of determination of minority carrier diffusion length in the base region of silicon solar cells

A new method of determination of the minority carrier diffusion length (L) in the base region of an n/sup +/-p-p/sup +/ silicon solar cell using the spectral response of the cell in a middle wavelength (/spl lambda/) range, e.g., 0.752.5, L=L/sub MW/ and is independent of S/sub B/. However, for d/L<2.5, the true value of L which may be somewhat different from L/sub MW/ can be determined if S/sub B/ is known. While most existing long wavelength spectral response (LWSR) methods require d/L to be large (d/L>2.5) is such that tanh(d/L)/spl ap/1, this method has no such restriction on d/L. It is highly suitable for cells for which L is large but x/sub b/ is small. We have applied the MWSR and LWSR methods to a few n/sup +/-p-p/sup +/ silicon solar cells and have found that the former is much superior to the latter if d/L<2.5.<
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