Assessment of intrinsic-layer growth temperature to high-deposition-rate a-Si:H n-i-p solar cells deposited by hot-wire CVD
The authors report progress in hydrogenated amorphous silicon n-i-p solar cells with the i-layer grown by the hot-wire chemical vapor deposition technique. Early research showed that they grew device-quality materials with low saturated defect density (2 x 10{sup 16}/cm{sup 3}), high initial ambipolar diffusion length ({approximately} 2,000 {angstrom}) and low hydrogen content (< 1%). One of the major barriers to implementing this material into solar cells is the high substrate temperature required (> 400 C). They re-assess the effects of low substrate temperature on the property of the films and the performance of the solar cells as an alternative avenue to solving this problem. They find that the material grown at 300 C can have similar values of saturated defect density and ambipolar diffusion length as the one grown greater than 400 C. They also study the effect of i-layer substrate temperature ranging from 280 to 440 C for n-i-p solar cells. They now consistently grow devices with Fill Factor (FF) greater than 0.66, with the best close to 0.70 at lower substrate temperature. A collaboration with United Solar System, in where they grew the p-layer and top contact, produced devices with initial efficiencies as high as 9.8%. They produce n-i-p solar cells with initial efficiencies as high as 8% when they grow all the hydrogenated amorphous silicon and top contact layers. All these i-layers are grown at deposition rates of 16 to 18 {angstrom}/sec. They need to further improve their p-layer and transparent conductor layer to equal the collaborative cell efficiency. They also report light-soaking results of these devices.
- Research Organization:
- National Renewable Energy Lab., Golden, CO (US)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC36-99GO10337
- OSTI ID:
- 20107901
- 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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