Irradiation-induced degradation in solar cell: characterization of recombination centres

Abstract

Although the defects introduced by irradiation in Si and GaAs have been extensively studied, the centres giving rise to non-radiative recombination have been neither characterized nor identified. We propose here a method allowing one to fully characterize recombination centres, i.e. to obtain their electron and hole capture cross sections as well as their concentration. It is based on a correlation between data extracted from the current–voltage characteristics of a junction in dark, deep level transient spectroscopy and the variations of the short-circuit current and open voltage of solar cells versus the logarithm of the irradiation fluence. The method is applied to characterize and tentatively identify the recombination centres introduced by electron irradiation in Si, GaAs and InGaP.