Investigation of Junction Properties in CdS/CdTe Solar Cells and Their Correlation to Device Properties: Preprint
Secondary-ion mass spectrometry analysis of the CdS/CdTe interface shows that S diffusion in CdTe increases with substrate temperature and CdCl2 heat treatment. There is also an accumulation of Cl at the interface for CdCl2-treated samples. Modulated photo-reflectance studies shows that devices with CdCl2 heat treatment and open-circuit voltage (Voc) of 835 mV have a distinct high electric-field region in the layer with bandgap of 1.45 eV. Electron-beam induced current measurements reveal a one-sided junction for high Voc devices. The nature of the junction changes with processing. For heterojunction devices, the depletion region includes the highly defective CdS/CdTe interface, which would increase the recombination current and consequently the dark current, leading to lower Voc. In the case of CdCl2-treated cells, the n+-p junction and its high electric-field results in the junction between structurally compatible CdTe and the Te-rich CdSTe alloy, and thus, in higher Voc.
- Research Organization:
- National Renewable Energy Lab. (NREL), Golden, CO (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC36-99-GO10337
- OSTI ID:
- 929607
- Report Number(s):
- NREL/CP-520-42567; TRN: US200813%%257
- Resource Relation:
- Conference: Presented at the 33rd IEEE Photovoltaic Specialists Conference, 11-16 May 2008, San Diego, California
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
36 MATERIALS SCIENCE
DIFFUSION
ELECTRIC POTENTIAL
HEAT TREATMENTS
HETEROJUNCTIONS
MASS SPECTROSCOPY
ORGANIC COMPOUNDS
PROCESSING
RECOMBINATION
SOLAR CELLS
SUBSTRATES
VOLATILE MATTER
CDS/CDTE
SECONDARY-ION MASS SPECTROMETRY
PHOTOREFLECTANCE
ELECTRIC-FIELD REGION
JUNCTION
ELECTRON-BEAM
Solar Energy - Photovoltaics