Structure and electronic studies of defects in amorphous silicon. Final report, March 1980-February 1981
Basic research of the structure and electronic properties of a-Si:H is reported with particular emphasis on the role of defects. The main findings are as follows: (1) low defect density material can be deposited at a high rate using SiH/sub 4/ diluted in He or Ne. Using Ar or Kr results in a high defect density and columnar material; (2) an electrical bias during deposition modifies the band gap, hydrogen concentration and structure; (3) the clustering of hydrogen in the regions between the columns is confirmed; (4) hydrogen diffusion is observed by NMR; (5) the oxidation of an a-Si:H surface results in approx. 3 x 10/sup 11/ cm/sup -2/ dangling bonds at the interface; (6) auger recombination of photoexcited carriers is a significant non-radiative mechanism at low temperatures; (7) non-radiative recombination by diffusion and capture at dangling bonds is observed at temperatures above 50 to 100/sup 0/K; (8) the defect density in doped and compensated a-Si:H is determined by the position of the Fermi energy. The mechanism for defect incorporation is believed to be autocompensation; (9) compensation results in extra hole traps above the valence band tail which are believed to be boron-phosphorus complexes; (10) dispersive transport of electrons and bimolecular recombinations determine the photoconductivity response over a wide time scale; (11) electron and hole transport effects and deep centers are observed in current transient DLTS measurements; (12) silicide formation occurs at the palladium/a-Si:H interface as a Pd/sub 2/Si layer; (13) the growth of silicide improves the electrical properties of Schottky barriers and gives ideal diodes; and (14) p-i-n solar cells of 5 to 6% efficiency have been made.
- Research Organization:
- Xerox Palo Alto Research Center, CA (USA)
- DOE Contract Number:
- AC03-79ET23033
- OSTI ID:
- 5985492
- Report Number(s):
- DOE/ET/23033-T4; ON: DE81029977
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
SILICON
CRYSTAL DEFECTS
MICROSTRUCTURE
AMORPHOUS STATE
ARGON
CHARGED-PARTICLE TRANSPORT
DEPOSITION
DIFFUSION
EFFICIENCY
ELECTRIC POTENTIAL
ENERGY GAP
HELIUM
HYDROGEN ADDITIONS
INTERFACES
KRYPTON
LUMINESCENCE
NEON
OXIDATION
PALLADIUM SILICIDES
PHOTOCONDUCTIVITY
RECOMBINATION
SCHOTTKY BARRIER DIODES
SILANES
TRAPS
CHEMICAL REACTIONS
CRYSTAL STRUCTURE
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ELEMENTS
FLUIDS
GASES
HYDRIDES
HYDROGEN COMPOUNDS
NONMETALS
PALLADIUM COMPOUNDS
PHYSICAL PROPERTIES
RADIATION TRANSPORT
RARE GASES
SEMICONDUCTOR DEVICES
SEMICONDUCTOR DIODES
SEMIMETALS
SILICIDES
SILICON COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
140501* - Solar Energy Conversion- Photovoltaic Conversion