Investigation of selected electrically active defects in polycrystalline silicon solar cell materials: Final subcontract report, 30 May 1986
This report presents results of a study on techniques for producing silicon wafers for large-scale, terrestrial, solar energy applications: ESP (edge-supported pulling) silicon sheets and LASS (low angle silicon sheets). Correlations between electrical properties and structural and microstructural properties were investigated. Structural properties were analyzed using selected area electron channeling (SAEC); electrical properties were described by means of electron-beam-induced current (EBIC). The transmission electron microscope (TEM) was used to analyze microstructural properties. It was found that the LASS material was semirandomly oriented. In general, the growth direction was parallel to the (211) family of planes. EBIC results of the ESP material showed long, linear bands of poor electrical response. EBIC results of the LASS material showed poor electrical response along grain boundaries and near silicon inclusions and dislocation clusters. TEM results showed a predominance of twins and stacking faults in both the ESP and LASS materials. The LASS material also exhibited grain boundaries, dislocation networks, and precipitates. The poor electrical response may be related to the stacking faults, grain boundaries, and dislocation networks presumably formed by the mechanical pulling during sheet formation. However, the dislocation networks often appeared to act as gettering sites to tie up impurities and thereby improve the overall electrical response of the material.
- Research Organization:
- Florida Univ., Gainesville (USA). Dept. of Materials Science and Engineering; Solar Energy Research Inst. (SERI), Golden, CO (United States)
- DOE Contract Number:
- AC02-83CH10093
- OSTI ID:
- 6889508
- Report Number(s):
- SERI/STR-211-3083; ON: DE87001159
- Resource Relation:
- Other Information: Portions of this document are illegible in microfiche products. Original copy available until stock is exhausted
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
36 MATERIALS SCIENCE
LASS GROWTH METHOD
DEFECTS
SILICON SOLAR CELLS
TRANSMISSION ELECTRON MICROSCOPY
CRYSTAL GROWTH METHODS
DIRECT ENERGY CONVERTERS
ELECTRON MICROSCOPY
EQUIPMENT
MICROSCOPY
PHOTOELECTRIC CELLS
PHOTOVOLTAIC CELLS
SOLAR CELLS
SOLAR EQUIPMENT
140501* - Solar Energy Conversion- Photovoltaic Conversion
360601 - Other Materials- Preparation & Manufacture