Indium phosphide/cadmium sulfide thin-film terrestrial solar cells. Quarterly report No. 4, July 1--September 14, 1977

Technical Report · Sat Oct 01 04:00:00 EDT 1977

DOI:https://doi.org/10.2172/5219186· OSTI ID:5219186

Zanio, K.; Fraas, L.

Indium phosphide/cadmium sulfide solar cells with AM2 efficiencies up to 7% were prepared by the deposition of CdS on single crystals of InP. When an intermediate layer of n-type InP was deposited by the planar reactive deposition (PRD) technique, 3% efficiencies were obtained. Reduced efficiencies were obtained when an intermediate layer of p-type Mn-doped InP was used as the light-absorbing layer. Manganese, acting as a deep center at 0.25 eV and introduced in concentrations of about 10/sup 18/ cm/sup -3/, may act as recombination and tunneling centers, thus limiting the efficiency of the cells. These results suggest that, to improve cell efficiency, either the Mn doping must be reduced or the purity of films must be improved. Methods of improving the purity of the films are suggested. Incorporating Zn as a dopant in the form of diethylzinc is proposed to provide a shallow center to replace Mn. An evaluation of thin films of InP prepared by PRD onto thin films of CdS and InP and sapphire substrates indicated that the InP grain boundaries are n-type, which results in intolerable high current paths through all-thin-film polycrystalline cells. Incorporating Zn as a dopant by diethylzinc is also proposed to provide a graded p to p/sup +/ structure, which would block the current at the grain boundaries. A recently implemented chemomechanical polishing technique has yielded smooth surfaces and complete coverage over single crystals of CdS.

• Research Organization: Hughes Research Labs., Malibu, Calif. (USA)
• OSTI ID: 5219186
• Report Number(s): ALO/3717-1
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
140501* -- Solar Energy Conversion-- Photovoltaic Conversion
36 MATERIALS SCIENCE
360601 -- Other Materials-- Preparation & Manufacture
CADMIUM SULFIDE SOLAR CELLS
CRYSTAL DOPING
CRYSTAL STRUCTURE
CRYSTALS
DEPOSITION
DIRECT ENERGY CONVERTERS
EFFICIENCY
FABRICATION
GRAIN BOUNDARIES
INDIUM COMPOUNDS
INDIUM PHOSPHIDES
MICROSTRUCTURE
MONOCRYSTALS
PHOSPHIDES
PHOSPHORUS COMPOUNDS
PHOTOELECTRIC CELLS
PHOTOVOLTAIC CELLS
PNICTIDES
SOLAR CELLS