Growth and characterization of thin film zinc-silicon-arsenide for solar cells
Many problems generally associated with heteroepitaxial growth of semiconducting materials were much in evidence. In particular, interfacial diffusion resulting in autodoping of both substrate and the grown epilayer precluded rectifying heterojunction formation for ZnSiAs/sub 2/ layers grown on Ge, GaAs or Si substrate. The lattice mismatch of about three percent between silicon and ZnSiAs/sub 2/ provided additional problems of microcracks in and nonadherence of the epilayers. This other set of problems was rectified by the in-situ growth of a silicon buffer layer just prior to the ZnSiAs/sub 2/ deposition. Blocking heterojunction formation was achieved between vacuum evaporated CdS at about 200/sup 0/C and 660/sup 0/C MO-CVD grown ZnSiAs/sub 2/ layers on Ge and Si (with a Si buffer layer). In the latter case a cascade structure resulted with photoresponse characteristics showing additive open circuit voltages for the two junctions. Models have been formulated for the dark-current transport in the n-CdS/ZnSiAs/sub 2/ heterojunctions and the photovoltaic spectral response in p-ZnSiAs/sub 2//n/sup +//p-Si structures. The current transport model envisages a trapping-recombination assisted tunneling mechanism in the heterojunctions. The ZnSiAs/sub 2/ layer plays a passive photo-attenuator role in the spectral response model. Computer simulations give close fit between the theory and experimental observations. Parameters deduced from experimental data and theoretical models include effective trapping density for 77/sup 0/ < T < 300/sup 0/K in the n-CdS/p-ZnSiAs/sub 2/ heterojunctions, carrier concentrations in ZnSiAs/sub 2/ and an electron affinity value for MO-CVD grown ZnSiAs/sub 2/ layer. This is the first time that an experimental value for the electron affinity in ZnSiAs/sub 2/ has been reported.
- OSTI ID:
- 6858713
- Resource Relation:
- Other Information: Thesis (Ph.D.)
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
SILICON ARSENIDES
CHEMICAL VAPOR DEPOSITION
ELECTRICAL PROPERTIES
OPTICAL PROPERTIES
ZINC ARSENIDES
CADMIUM SULFIDES
COMPUTERIZED SIMULATION
CRYSTAL MODELS
DOPED MATERIALS
FILMS
GALLIUM
GERMANIUM
HIGH TEMPERATURE
LOW TEMPERATURE
MEASURING METHODS
MEDIUM TEMPERATURE
PRODUCTION
SEMICONDUCTOR MATERIALS
SILICONES
SOLAR CELLS
ARSENIC COMPOUNDS
ARSENIDES
CADMIUM COMPOUNDS
CHALCOGENIDES
CHEMICAL COATING
DEPOSITION
DIRECT ENERGY CONVERTERS
ELEMENTS
EQUIPMENT
INORGANIC PHOSPHORS
MATERIALS
MATHEMATICAL MODELS
METALS
ORGANIC COMPOUNDS
ORGANIC SILICON COMPOUNDS
PHOSPHORS
PHOTOELECTRIC CELLS
PHOTOVOLTAIC CELLS
PHYSICAL PROPERTIES
PNICTIDES
POLYMERS
SILICON COMPOUNDS
SILOXANES
SIMULATION
SOLAR EQUIPMENT
SULFIDES
SULFUR COMPOUNDS
SURFACE COATING
ZINC COMPOUNDS
140501* - Solar Energy Conversion- Photovoltaic Conversion