Role of bandgap grading for the performance of microcrystalline silicon germanium solar cells
The optical absorption of microcrystalline silicon germanium alloys ({micro}c-Si{sub 1{minus}x}Ge{sub x}:H) increases in the near infrared region with increasing germanium content. Therefore, these alloys are promising candidates for the application as intrinsic absorber material in thin film solar cells with tandem and triple structure or IR-detectors. The material properties for a germanium content (x) up to 0.6 and the performance of solar cells based on this material were investigated. Graded bandgap structures are used to optimize the cell performance. For cells with x > 0.3 a continuously graded bandgap in the rear 20 nm of the i-layer (at the i/n interface) results in an enhancement of the open circuit voltage by 40--80 mV compared to an abrupt bandgap discontinuity. When the design of the p/i interface region is changed in a similar way no effect on V{sub oc} is observed.
- Research Organization:
- Forschungszentrum Juelich GmbH (DE)
- OSTI ID:
- 20107958
- Resource Relation:
- Conference: 1999 Materials Research Society Spring Meeting, San Francisco, CA (US), 04/05/1999--04/09/1999; Other Information: PBD: 1999; Related Information: In: Amorphous and heterogeneous silicon thin films: Fundamentals to devices -- 1999. Materials Research Society symposium proceedings: Volume 557, by Branz, H.M.; Collins, R.W.; Okamoto, Hiroaki; Guha, S.; Schropp, R. [eds.], 908 pages.
- Country of Publication:
- United States
- Language:
- English
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