Self-Compensation in Arsenic Doping of CdTe

Tursun Ablekim, Santosh K. Swain, Wan Jian Yin, Katherine Zaunbrecher, James Burst, Teresa M. Barnes, Darius Kuciauskas, Su Huai Wei, Kelvin G. Lynn

Research output: Contribution to journalArticlepeer-review

60 Scopus Citations

Abstract

Efficient p-Type doping in CdTe has remained a critical challenge for decades, limiting the performance of CdTe-based semiconductor devices. Arsenic is a promising p-Type dopant; however, reproducible doping with high concentration is difficult and carrier lifetime is low. We systematically studied defect structures in As-doped CdTe using high-purity single crystal wafers to investigate the mechanisms that limit p-Type doping. Two As-doped CdTe with varying acceptor density and two undoped CdTe were grown in Cd-rich and Te-rich environments. The defect structures were investigated by thermoelectric-effect spectroscopy (TEES), and first-principles calculations were used for identifying and assigning the experimentally observed defects. Measurements revealed activation of As is very low in both As-doped samples with very short lifetimes indicating strong compensation and the presence of significant carrier trapping defects. Defect studies suggest two acceptors and one donor level were introduced by As doping with activation energies at ~88 meV, ~293 meV and ~377 meV. In particular, the peak shown at ~162 K in the TEES spectra is very prominent in both As-doped samples, indicating a signature of AX-center donors. The AX-centers are believed to be responsible for most of the compensation because of their low formation energy and very prominent peak intensity in TEES spectra.

Original languageAmerican English
Article numberArticle No. 4563
Number of pages9
JournalScientific Reports
Volume7
Issue number1
DOIs
StatePublished - 1 Dec 2017

Bibliographical note

Publisher Copyright:
© 2017 The Author(s).

NREL Publication Number

  • NREL/JA-5K00-68633

Keywords

  • arsenic
  • CdTe
  • compensation
  • doping

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