Determination of diffusion length and grain boundary recombination velocity by laser excitation

A new technique is developed here for accurately evaluating the diffusion length and the grain-boundary recombination velocity in a semiconductor bicrystal from photovoltage measurements taken by scanning of a laser "infinite line" parallel to the grain boundary. The present method can also be applied in semiconductor bicrystals of small diffusion length, in contrast to a previous scanning laser spot technique, which is limited by the spot size. Experimental application shows that the values of diffusion length and grain boundary recombination velocity measured with the present method are in very good agreement with the values measured in previous work in similar materials.