Behaviour of amorphous silicon solar modules: A parameter study

• Two-diode-model for aSi:H modules.
• A parameter study for showing the influence of the single parameters to the I–V-curve.
• Enabling to model the SWE.
• No significant influence of the shunt resistance.

In contrast to crystalline silicon solar modules the parameters of the I–V-curve cannot directly be extracted by one measured I–V-curve for amorphous solar modules. Especially the parasitical series and shunt resistance are not comparable to the slope in the short circuit respectively to the open circuit region of the I–V-curve. This work will show the behaviour of the I–V-curve of aSi:H solar modules and the influence of the single curve parameters. The influence of the separate parameters of aSi:H solar cells is more difficult to understand than for crystalline silicon. So a parameter study shows the influence of the parameters to the I–V-curve. A recombination current allows a more sufficient description of the recombination paths under illumination. The so called Merten-Model is sufficient to describe the curves behaviour. But to understand the degradation mechanism a more detailed model is needed. Thereto a second diode in the model allows a more exhaustive study of the degradation mechanism, especially the Staebler-Wronski-Effect.