STUDY OF GERMANIUM DEVICES FOR USE IN A THERMOPHOTOVOLTAIC CONVERTER.
Progress rept. no. 1, 1 Jul 66-1 Jan 67,
GENERAL MOTORS CORP KOKOMO IND DELCO RADIO DIV
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An investigation was made of the front junction PN absorptive device structure since it was felt that this device might be inherently more stable and exhibit higher values of collection efficiency. Values of collection efficiency approaching 100 were obtained but the stability in vacuum is not improved over the NP configuration. Power output of the PN is limited by the curve factor at P dopings of 10 to the 18th powercu cm. Increased doping of the P region seriously degrades device collection efficiency. The complete reversibility of the vacuum degradation and its dependence on I sub sc levels were determined. Vacuum coating work has been extended to include silicon dioxide, silicon carbide, cadmium sulfide and others in the electron beam evaporator. None of these contributes to device stability. Increased stability of ZnS coated devices was demonstrated. Attempts to fabricate NP devices by epitaxial deposition were unsuccessful because of doping problems. Sufficient P-type layers were not obtained resulting in poor diode structures. The decision to discontinue the epitaxial work was made. Continued development of polishing techniques yielded NP nonabsorptive devices with negligible scattering losses before electroetching. Author
- Electrical and Electronic Equipment
- Non-electrical Energy Conversion