Photovoltaic properties of reactively sputtered Cu/sub x/S--CdS heterojunctions
The use of sputtering techniques as an attractive means of fabricating low-cost thin film solar cells has been studied for the Cu/sub x/S-CdS heterojunction system. Control of the Cu/sub x/S stoichiometry is done using variable partial pressures of H/sub 2/S in a reactive sputtering mode with excellent results. Measured optical absorption spectra, film resistivity, and x-ray diffraction analysis verify the consistent formation of chalcocite. TEM electron diffraction studies indicate epitaxial formation of the reactively sputtered Cu/sub x/S on CdS consistent with a measured interface recombination velocity, S/sub I/, of 2 x 10/sup 5/ cm/sec. Cell forward and reverse I-V characteristics are also dominated by tunneling processes, as has been observed for wet-dip Cu/sub x/S-CdS heterojunctions. Measured minority carrier diffusion lengths, L/sub e/, of equal to or greater than 1000 A in the Cu/sub x/S, coupled with significant red response of heterojunction cells, verify the suitability of reactively sputtered Cu/sub x/S for efficient cell fabrication. Cell efficiencies of 4% have been obtained and are limited at present by technological factors including cell shorting and surface roughness problems.
- Research Organization:
- California Univ., Livermore (USA). Lawrence Livermore Lab.
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 6748500
- Report Number(s):
- UCRL-81199; CONF-780619-11
- Resource Relation:
- Conference: IEEE photovoltaic specialists conference, Washington, DC, USA, 5 Jun 1978
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
36 MATERIALS SCIENCE
CADMIUM SULFIDE SOLAR CELLS
ELECTRICAL PROPERTIES
PHOTOVOLTAIC EFFECT
COPPER SULFIDES
SPUTTERING
CARRIER MOBILITY
ELECTRIC CONDUCTIVITY
EPITAXY
FABRICATION
STOICHIOMETRY
CHALCOGENIDES
COPPER COMPOUNDS
DIRECT ENERGY CONVERTERS
MOBILITY
PHOTOELECTRIC CELLS
PHOTOVOLTAIC CELLS
PHYSICAL PROPERTIES
SOLAR CELLS
SULFIDES
SULFUR COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
140501* - Solar Energy Conversion- Photovoltaic Conversion
360601 - Other Materials- Preparation & Manufacture