Investigation of light and dark I-V characteristics of a-Si:H alloy solar cells, irradiated with 1.0 MeV protons

Light and dark I-V characteristics of both virgin and irradiated solar cells with the same history differ; the objective of this work is to elucidate the mechanisms responsible for the observations. Thirty-seven triple-junction and 120 single-junction hydrogenated amorphous silicon alloy cells were investigated. Triple and single-junction cells degrade similarly with 1.0 MeV proton irradiation; the power density degrades for fluences above 1E12 cm^-2. The fill-factor degrades initially; above 5E13 cm^-2 the short-circuit current density dominates the degradation. Dark I-V measurements show changes in the shunt resistance and injection current. High fluences tend to decrease both the shunt and injection currents. Shunt resistances of virgin cells are unstable under reverse bias. Annealing at 200°C for two hours increases and stabilizes shunt resistances. A parametric model was used to fit light and dark I-V measurements. The effect of irradiation and light bias on the parameters is reported