Effect of Localized Recombination Planes on Minority-Carrier Diffusion Length in Silicon Solar Cells

Abstract

The spatial variation of minority-carrier diffusion length in the vicinity of a stress-relieved boundary surface in monocrystalline and semicrystalline silicon solar cells has been measured for the first time by the scanned monochromatic light beam induced current (MBIC) technique with a very small spot size (2 µmφ) and 750–1050 nm long-wavelength light beam. The technique we developed uses a short-arc xenon lamp source with line spectra. It was found that the effect of a boundary surface extended beyond the distance of minority-carrier diffusion length. Furthermore, it was indicated that the output currents of semicrystalline silicon cells could be described by a monocrystalline device model using the concet of the effective minority-carrier diffusion length.