Abstract
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-fieldregion 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. Inthe 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.
Original language | American English |
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Number of pages | 8 |
State | Published - 2008 |
Event | 33rd IEEE Photovoltaic Specialists Conference - San Diego, California Duration: 11 May 2008 → 16 May 2008 |
Conference
Conference | 33rd IEEE Photovoltaic Specialists Conference |
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City | San Diego, California |
Period | 11/05/08 → 16/05/08 |
NREL Publication Number
- NREL/CP-520-42567
Keywords
- CdS/CdTe
- electric-field region
- electron-beams
- junctions
- photoreflectance
- secondary ion mass spectrometry (SIMS)