Schottky barrier and homojunction gallium arsenide solar cells
New techniques were developed to construct Schottky barrier and homojunction solar cells on GaAs substrates. Schottky barrier metal-semiconductor solar cells were produced for the first time on p-type GaAs substrate using a sputter-deposition method to form the barrier. The sputter deposition of gold or gold/palladium is the key to the method since normal thermal evaporation of gold onto p-type GaAs produces ohmic contacts. The results of this investigation are consistent with the idea that sputter damage produces donor type surface states on GaAs. Barrier heights were measured for both p-type sputtered and n-type thermally evaporated diodes using current-voltage and capacitance-voltage methods. Deep-level transient spectroscopy was used to identify the trap center concentration and energy levels for both diodes in an effort to explain the relatively large dark current in the p-type sputtered diodes. Homojunction GaAs solar cells were fabricated using several techniques. One involved using closed-tube diffusion to form the junction. The primary problem with the method was controlling the junction depth to maximize short-circuit current. Junction depth was found to be a strong function of diffusion conditions and substrate parameters. Another promising method studied involved ion-implantation to form the junction. A Q-switched ruby laser was used to fabricate heterojunction solar cells. These cells were made by growing an AlGaAs layer on n-type GaAs using laser pulse alloying of a very thin Al film. While these cells were not as good as others produced in this thesis the feasibility of the method was established.
- OSTI ID:
- 5574410
- Resource Relation:
- Other Information: Thesis (Ph. D.)
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
GALLIUM ARSENIDE SOLAR CELLS
FABRICATION
SCHOTTKY BARRIER SOLAR CELLS
ANNEALING
HOMOJUNCTIONS
ION IMPLANTATION
RUBY LASERS
SPUTTERING
SUBSTRATES
DIRECT ENERGY CONVERTERS
EQUIPMENT
HEAT TREATMENTS
JUNCTIONS
LASERS
PHOTOELECTRIC CELLS
PHOTOVOLTAIC CELLS
SEMICONDUCTOR JUNCTIONS
SOLAR CELLS
SOLAR EQUIPMENT
SOLID STATE LASERS
140501* - Solar Energy Conversion- Photovoltaic Conversion