Diffusion length analysis and measurement in the base region of photodiodes

Abstract

An experimental technique for determining the minority carrier diffusion length in the base region of SI photodiodes described. Optical arrangement has been suggested, in which the device was operated in the photoconductive mode and its photo-response in the wavelength region near the energy gap is measured. The ratio of incident light intensity to photocurrent is a linear function of reciprocal absorption coefficient the slope of which gives L n . In addition, a nonlinear least-squares analysis is also used to determine the diffusion length. Furthermore, it has been found that L n decreases as the absorbed dose of gamma rays increases.