Elimination of Te inclusions in Cd 1-xZn xTe crystals by short-term thermal annealing

P. Fochuk, R. Grill, O. Kopach, A. E. Bolotnikov, E. Belas, M. Bugar, G. Camarda, W. Chan, Y. Cui, A. Hossain, K. H. Kim, I. Nakonechnyi, O. Panchuk, G. Yang, R. B. James

Research output: Contribution to journalArticle

21 Citations (Scopus)

Abstract

The presence of Te inclusions degrades the quality of today's CdZnTe (CZT) crystals used for X- and gamma-ray detectors; both their sizes and concentrations densities must be reduced. Over the past years, many researchers proposed using long-term annealing (> 24 h) under Cd vapor pressure to reduce or even eliminate the inclusions visible under IR microscopes. We annealed detector-grade CZT samples for periods of 15 to 60 min under Cd-, Zn-, or Te-overpressure or in vacuum at 1000-1200 K. We determined the optimal temperature, duration, and the vapor atmosphere for such high-temperature annealing, typically at ∼1100 K for 0.5-1.0 h. The results were very promising in eliminating Te-rich inclusions, even on twins where the inclusions are more stable than in the unperturbed lattice; indeed, we saw almost no inclusions whatsoever by IR transmission microscopy after such annealing. We note that eliminating inclusions at lower temperatures takes much longer. However, annealing under a Cd vapor pressure at temperatures above ∼1170 K generates a large quantity of irregular Cd inclusions. The samples' resistance after annealing was estimated by I-V curves.

Original languageEnglish
Article number6165397
Pages (from-to)256-263
Number of pages8
JournalIEEE Transactions on Nuclear Science
Volume59
Issue number2
DOIs
Publication statusPublished - 2012 Apr

Keywords

  • Annealing
  • Cd Zn Te
  • component overpressure
  • crystals
  • inclusions

ASJC Scopus subject areas

  • Nuclear and High Energy Physics
  • Nuclear Energy and Engineering
  • Electrical and Electronic Engineering

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    Fochuk, P., Grill, R., Kopach, O., Bolotnikov, A. E., Belas, E., Bugar, M., Camarda, G., Chan, W., Cui, Y., Hossain, A., Kim, K. H., Nakonechnyi, I., Panchuk, O., Yang, G., & James, R. B. (2012). Elimination of Te inclusions in Cd 1-xZn xTe crystals by short-term thermal annealing. IEEE Transactions on Nuclear Science, 59(2), 256-263. [6165397]. https://doi.org/10.1109/TNS.2012.2187069