Influence of the spatial distribution of metastable defects on the properties of degraded a-Si:H solar cells

The degradation behaviour of standard a-Si:H p-i-n and n-i-p solar cells after light soaking, current injection and keV-electron irradiation is investigated. Utilizing the energy dependence of the penetration depth of the keV-electrons, different spatial distributions of metastable defects were created in the solar cells. A strong influence of the induced defect profiles on the reductions of the solar cell performance parameters j/sub sc/, V/sub oc/, FF and /spl eta/ is found. Applying the different degradation techniques only weak differences in the corresponding internal collection efficiency measurements q(/spl lambda/, U) were observed for the n-i-p solar cells, while a characteristic shift of the crossing point of the q(/spl lambda/, U) curves depending on the defect distribution was noticed for the p-i-n cells. The results of the experiments indicate the degradation of the bulk to be the dominant effect after light soaking in the p-i-n and n-i-p cells investigated in this study.