Surface stoichiometry of pulsed ultraviolet laser treated polycrystalline CdTe

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Publication Type pre-print
School or College College of Engineering
Department Materials Science & Engineering
Creator Scarpulla, Michael
Other Author Simonds, Brian J.; Palekis, Vasilios; Van Devener, Brian; Ferekides, Christos
Title Surface stoichiometry of pulsed ultraviolet laser treated polycrystalline CdTe
Date 2014-01-01
Description The effects of nanosecond pulsed ultraviolet laser annealing on the surface stoichiometry of close-space sublimated polycrystalline thin films are investigated using angle-resolved x-ray photoemission spectroscopy (XPS). The raw data suggest the formation of a Cd-rich surface layer, but this is counter to the expectation based on Cd and Te vapor pressures above CdTe that predicts a Te-rich layer and to direct observation of elemental Te at the surface. In order to explain this apparent discrepancy, we analyze our XPS data in the context of prior reports of lateral segregation of Cd and Te at the surface after pulsed laser treatments with a simple model of angular dependent XPS in the presence of surface roughness. This analysis reveals that a uniform Te layer cannot explain our results. Instead, our analysis suggests that Te enrichment occurs near grain boundaries and that a sub-monolayer Cd layer exists elsewhere. These complex yet repeatable results underscore the challenges in measuring surface stoichiometry to high precision on films relevant for polycrystalline CdTe devices. It also suggests that the Cd and Te vapor pressures above grain boundaries may differ from those above grain interiors and that ohmic contact may be made preferentially at the grain boundaries after pulsed laser annealing.
Type Text
Publisher American Institute of Physics (AIP)
Volume 116
Issue 1
First Page 013506-1
Last Page 013506-8
Language eng
Bibliographic Citation Simonds, B. J., Palekis, V., Van Devener, B., Ferekides, C., & Scarpulla, M. A. (2014). Surface stoichiometry of pulsed ultraviolet laser treated polycrystalline CdTe. Journal of Applied Physics, 116(1), 013506-1-013506-8.
Rights Management (c)American Institute of Physics. The following article appeared in Simonds, B. J., Palekis, V., Van Devener, B., Ferekides, C., & Scarpulla, M. A., Journal of Applied Physics, 116(1) 2014. and may be found at http://dx.doi.org/10.1063/1.4887079.
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Reference URL https://collections.lib.utah.edu/ark:/87278/s69d06hn