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Title: Investigation of thin film solar cells based on Cu/sub 2/S and certain ternary compounds. Final report, July 1, 1973--December 31, 1976

Technical Report ·
OSTI ID:6601937

Copper sulfides, especially chalcocite (Cu/sub x/S with 2.000 < or = x < or = 1.995) and CuInS/sub 2/ have been studied as semiconductors for photovoltaic solar cell applications. Thin films (0.1 to 0.5..mu..) of copper sulfides have been produced by sulfurizing thinner films of evaporated copper and by chemical substitution of Cu ions for Cd ions in CdS single crystals and thin films. They have been characterized by x-ray diffraction, cathodoluminescence, optical transmission and reflectance, conductivity, Auger spectroscopy and scanning electron microscope analysis. Only chalocite and a tetragonal phase of composition Cu/sub x/S with x approximately 1.94 luminesce. Thin films of djurleite or diginite could not be produced by sulfurization. Solar cells involving heterojunctions between chalcocite and single crystals of n-CdS and n-Si have been fabricated and characterized. In the case of CdS substrate cells, the highest efficiencies (approximately 4%) were encountered when the Cu/sub x/S layer was produced by the Philips process; the next best, when the Cu/sub x/S layer was produced by the Clevite process (eta approximately 3%) and the poorest when the Cu/sub x/S layer was produced by sulfurizing a previously deposited thin film of Cu (eta approximately 2%) even though cathodoluminescence (CL) shows that the chalcocite produced by sulfurization is pure, whereas the chalcocites derived from CdS have a CL spectrum distinctly different from what is known to be pure chalcocite. The studies also show that the CL spectrum of the chalcocite derived from CdS changes with time whereas the sulfurized chalcocite is stable with time. A CL study of the effects of post fabrication treatments on chalcocite is also reported. Heterojunctions formed between p-chalcocite and n-Si have efficiencies up to about 4% and potential efficiencies up to 10%. The work on CuInS/sub 2/ was concentrated on preparation of single crystals and their characterization by x-ray analysis and CL.

Research Organization:
Brown Univ., Providence, RI (USA). Div. of Engineering
OSTI ID:
6601937
Report Number(s):
TID-28692
Resource Relation:
Other Information: Portions of document are illegible
Country of Publication:
United States
Language:
English