Bias Light Wavelength Dependence of Minority Carrier Diffusion Length of EFG Silicon Ribbon Solar Cells

Abstract

Local spectral photoresponse of EFG ribbon solar cells was measured as a function of bias light wavelength and intensity. The bias light wavelength was found to have small influence on the spectral response in local positions with longer (≃89 µm) and shorter (≃7 µm) diffusion length, but large influence on that in positions with medium diffusion length (≃20 µm). The effective minority carrier diffusion length estimated from the spectral response measurement was found to increase semilogarithmically with the intensity at various bias light wavelengths. The effect of bias light wavelength on diffusion length is explained by the penetration depth of bias light into solar cells.