Effects of 40 keV electron irradiation on dark I-V characteristics of single-junction a-Si:H solar cells

The effects of 40 keV electron irradiations and anneals on dark I-V characteristics of a single-junction a-Si:H solar cell have been investigated. A parametric fitting model was used to identify the current mechanisms by comparing the measured and calculated I-V. A single current injection term fits the dark I-V characteristics before irradiation. Two additional terms had to be introduced following 40 keV electron irradiations with fluences of about 1E17 cm^-2: one is a shunt term and the other is a term of the form CV^m. The current mechanism characterized by the CV^m term was removed by annealing for two hours at 140°C. Subsequent irradiation restores the current mechanism and it is readily removed by another annealing cycle. Initial work is reported on the use of a device simulator to determine the effect of irradiation on the material properties