Effect of Dual-Function Nano-Structured Silicon Oxide Thin Film on Multi-Junction Solar Cells
We present our recent study of using nano-structured hydrogenated silicon oxide films (nc-SiO{sub x}:H) as a dual-function layer in multi-junction solar cells. The nc-SiO{sub x}:H films were deposited using very high frequency glow discharge of a SiH{sub 4} (or Si{sub 2}H{sub 6}), CO{sub 2}, PH{sub 3}, and H{sub 2} gas mixture. By optimizing deposition parameters, we obtained 'dual function' nc-SiO{sub x}:H material characterized by a conductivity suitable for use as an n layer and optical properties suitable for use as an inter-reflection layer. We tested the nc-SiO{sub x}:H by replacing the normal n-type material in the tunnel junction of a multi-junction structure. The advantage of the dual-function nc-SiO{sub x}:H layer is twofold; one is to simplify the cell structure, and the other is to reduce any optical loss associated with the inter-reflection layer. Quantum efficiency measurements show the gain in top cell current is equal to or greater than the loss in bottom cell current for a-Si:H/nc-Si:H structures. In addition, a thinner a-Si:H top cell with the nc-SiO{sub x}:H n layer improves the top-cell stability, thereby providing higher stabilized solar cell efficiency. We also used the dual-function layer between the middle and the bottom cells in a-Si:H/a-SiGe:H/nc-Si:H triple-junction structures. The gain in the middle cell current is {approx}1.0 mA/cm{sup 2}, leading to an initial active-area efficiency of 14.8%.
- Research Organization:
- National Renewable Energy Lab. (NREL), Golden, CO (United States)
- Sponsoring Organization:
- USDOE Office of Energy Efficiency and Renewable Energy Solar Energy Technologies Program
- DOE Contract Number:
- AC36-08GO28308
- OSTI ID:
- 1048598
- Resource Relation:
- Conference: [Proceedings] 37th IEEE Photovoltaic Specialists Conference (PVSC '11), 19-24 June 2011, Seattle, Washington
- Country of Publication:
- United States
- Language:
- English
Similar Records
Final Report: Vapor Transport Deposition for Thin Film III-V Photovoltaics
Photoelectrochemical Hydrogen Production