Experimental and Theoretical Comparison of Sb, As, and P Diffusion Mechanisms and Doping in CdTe: Article No. 075102

Eric Colegrove, Steven Harvey, Matthew Young, Joel Duenow, David Albin, Wyatt Metzger, Ji-Hui Yang, Su-Huai Wei, James Burst

Research output: Contribution to journalArticlepeer-review

50 Scopus Citations

Abstract

Fundamental material doping challenges have limited CdTe electro-optical applications. In this work, the As atomistic diffusion mechanisms in CdTe are examined by spatially resolving dopant incorporation in both single-crystalline and polycrystalline CdTe over a range of experimental conditions. Density-functional theory calculations predict experimental activation energies and indicate As diffuses slowly through the Te sublattice and quickly along GBs similar to Sb. Because of its atomic size and associated defect chemistry, As does not have a fast interstitial diffusion component similar to P. Experiments to incorporate and activate P, As, and Sb in polycrystalline CdTe are conducted to examine if ex-situ Group V doping can overcome historic polycrystalline doping limits. The distinct P, As, and Sb diffusion characteristics create different strategies for increasing hole density. Because fast interstitial diffusion is prominent for P, less aggressive diffusion conditions followed by Cd overpressure to relocate the Group V element to the Te lattice site is effective. For larger atoms, slower diffusion through the Te sublattice requires more aggressive diffusion, however further activation is not always necessary. Based on the new physical understanding, we have obtained greater than 10^16 cm^-3 hole density in polycrystalline CdTe films by As and P diffusion.
Original languageAmerican English
Number of pages8
JournalJournal of Physics D: Applied Physics
Volume51
Issue number7
DOIs
StatePublished - 2018

NREL Publication Number

  • NREL/JA-5K00-68501

Keywords

  • CdTe
  • DFT
  • diffusion
  • doping

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