Intermixing at the CdS/CdTe interface and its effect on device performance
- National Renewable Energy Lab., Golden, CO (United States)
A study of the CdS/CdTe interface was performed on glass/SnO{sub 2}/CdS/CdTe device structures. CdS layers were deposited by chemical solution growth to a thickness of 80--100 nm, and CdTe was deposited by close-spaced sublimation at substrate temperatures of 500, 550, and 600 C. Post-deposition CdCl{sub 2} heat treatment was performed at 400 C. Samples were analyzed by optical spectroscopy, secondary ion mass spectrometry (SIMS), spectral response, and current-voltage measurements. SIMS analysis shows that the intermixing of CdS and CdTe is a function of substrate temperature and post-deposition CdCl{sub 2} heat treatment. The degree of intermixing increases with increases in substrate temperature and the intensity of CdCl{sub 2} heat treatment. Optical analysis and X-Ray diffraction data show that the phases of CdS{sub x}Te{sub 1{minus}x} are also a function of the same parameters. Formation of a Te-rich CdS{sub x}Te{sub 1{minus}x} alloy is favored for films deposited at higher substrate temperatures. Spectral response of the devices is affected by the degree of alloying at the interface. The degree of alloying is indicated by simultaneous changes in long wavelength response (due to the formation of lower bandgap intermixed CdS{sub x}Te{sub 1{minus}x}) and the short wavelength response (due to the change in CdS thickness). Device performance is heavily influenced by alloying at the interface. With optimized intermixing, improvements in V{sub oc} and diode quality factors are observed in the resulting devices.
- DOE Contract Number:
- AC36-83CH10093
- OSTI ID:
- 417698
- Report Number(s):
- CONF-960401--; ISBN 1-55899-329-0
- Country of Publication:
- United States
- Language:
- English
Similar Records
Influence of CdS/CdTe interface properties on the device properties
Effect of CdCl{sub 2} treatment of CdS films on CdTe/CdS solar cells
Related Subjects
36 MATERIALS SCIENCE
BOROSILICATE GLASS
CADMIUM CHLORIDES
CADMIUM SULFIDES
CADMIUM TELLURIDE SOLAR CELLS
CADMIUM TELLURIDES
CHEMICAL COATING
CURRENT DENSITY
DIFFUSION
EFFICIENCY
ELECTRIC POTENTIAL
ETCHING
FABRICATION
GRAIN BOUNDARIES
GRAIN SIZE
HEAT TREATMENTS
ION MICROPROBE ANALYSIS
MASS SPECTROSCOPY
MICROSTRUCTURE
MORPHOLOGY
PERFORMANCE
PHYSICAL VAPOR DEPOSITION
SPECTRAL RESPONSE
SUBSTRATES
TIN OXIDES
TRANSMISSION ELECTRON MICROSCOPY