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Title: Cadmium sulfide/copper sulfide heterojunction cell research by sputter deposition. Quarterly technical progress report, March 1, 1981-June 30, 1981

A second series of hybrid cells with sputter-deposited Cu/sub 2/S layers has been fabricated. An efficiency of about 4 3/4%, without antireflection coating, was achieved for one of the cells. This result approaches the 5 3/4% which was achieved in the first set (different Cu/sub 2/S deposition conditions) and confirms the viability of the sputtering process for this application. Significant progress has been made in fabricating all-sputtered cells with CdS layers deposited by planar magnetron reactive sputtering. Efficiencies of approximately 3%, without antireflection coatings, have been achieved in the as-deposited state for seven cells. Individual cells have yielded a J/sub sc/ of 12 mA/cm/sup 2/, a V/sub oc/ of 0.53V, and a fill factor of 0.72. Taken together these parameters would yield an efficiency of 4 1/2%. A strong coupling is found between the properties of the Cu/sub 2/S and CdS layers. However, the conditions which maximize J/sub sc/, V/sub oc/ and the fill factor do not appear to be mutually exclusive. Reflectance measurements indicate that 30% or more of the incident radiation is being reflected from the front surface of the cells over the wavelength range of the solar spectrum. Thus optimization of the cell parameters with a suitablemore » antireflection coating should yield cell efficiencies of about 6%. Characterization of the junctions formed in the all-sputtered cells under near-optimum deposition conditions indicates that they have remarkable properties in their as-deposited state, being very similar to high performance conventional cells after heat treatment. Junction ideality factors are about unity in the light, with J/sub 0/ values of about 2 x 10/sup -8/ mA/cm/sup 2/. Interface recombination velocities are as low as a few times 10/sup 5/ cm/sec. CdS depletion layer widths are about 2000 nm in the dark and collapse to about 200 nm under illumination.« less
Authors:
; ;
Publication Date:
OSTI Identifier:
5618874
Report Number(s):
SERI/PR-9296-T2
ON: DE82006851
DOE Contract Number:
AC02-77CH00178
Resource Type:
Technical Report
Research Org:
Solar Energy Research Inst., Golden, CO (USA); TELIC Corp., Santa Monica, CA (USA)
Country of Publication:
United States
Language:
English
Subject:
14 SOLAR ENERGY; CADMIUM SULFIDE SOLAR CELLS; ELECTRIC CURRENTS; SPUTTERING; COPPER SULFIDES; ANTIREFLECTION COATINGS; DEPLETION LAYER; DESIGN; EFFICIENCY; ELECTRIC POTENTIAL; FABRICATION; FILL FACTORS; HETEROJUNCTIONS; MAGNETRONS; OPTIMIZATION; PHOTOLUMINESCENCE; RECOMBINATION; REFLECTIVITY; CHALCOGENIDES; COATINGS; COPPER COMPOUNDS; CURRENTS; DIRECT ENERGY CONVERTERS; ELECTRON TUBES; ELECTRONIC EQUIPMENT; EQUIPMENT; JUNCTIONS; LAYERS; LUMINESCENCE; MICROWAVE EQUIPMENT; MICROWAVE TUBES; OPTICAL PROPERTIES; PHOTOELECTRIC CELLS; PHOTOVOLTAIC CELLS; PHYSICAL PROPERTIES; SEMICONDUCTOR JUNCTIONS; SOLAR CELLS; SOLAR EQUIPMENT; SULFIDES; SULFUR COMPOUNDS; SURFACE PROPERTIES; TRANSITION ELEMENT COMPOUNDS 140501* -- Solar Energy Conversion-- Photovoltaic Conversion