Surface recombination effects in soft x-ray efficiencies

Abstract

We have measured the soft x-ray efficiencies of a silicon p-i-n photodiode and a La2O2S:Tm phosphor over a broad energy range. We have also measured the inelastic electron scattering spectra of the constituent materials and obtained values of optical absorption coefficients versus energy. The energy dependence of the efficiencies is well explained by a model based on surface recombination of electron hole pairs, and the quality of data which can now be obtained from synchrotrons makes possible quantitative fits from which we obtain diffusion length, surface recombination velocity, and bulk quantum efficiency.