Transient and steady-state measurement and simulations of deep trap effects in crystalline and amorphous silicon solar cells

Two different nondestructive measurement techniques have been used to characterize deep level impurities in crystalline and amorphous Si solar cells. It is shown that, depending on the solar cell material, differential spectral responsivity (DSR) measurements at various irradiance levels below 10³ Wm^-2 can give a general insight into the behavior of traps. Short-circuit current response (SCCR) measurements have been carried out. These are based on the analysis of the charge deficiency of a solar cell at the onset of an irradiation pulse as a function of the preceding dark interval. These measurements at different temperatures between 90 K and 350 K are supplemented by computer simulations using SRH theory. Both the DSR and SCCR results are explained by these simulations