Influence of band gap grading of intrinsic layer and annealing post on the optical and electrical performance of amorphous silicon germanium thin film solar cells

Abstract

Hydrogenated amorphous silicon germanium (a-SiGe:H) single junction pin sequence solar cells with different bandgap structure of intrinsic layer were prepared by radio frequency plasma enhanced chemical vapor deposition (RF-PECVD). Three kinds type of intrinsic layer using in this study were non-grading structure, V type grading and reverse V type grading. The effects of different intrinsic layer structure on solar cell performance were systematically studied. The results showed that the optimized structure of intrinsic layer was the reverse V type grading structure. And the performance of a-SiGe:H solar cell with reverse V type grading after annealing also were studied. The results revealed that the performance was improved after first annealing, but was deteriorate for further annealing. And, we have studied the dark I-V curves in order to contribute to a better understanding of the basis of solar cells.