Photoconductivity in Tl 6 SI 4: A novel semiconductor for hard radiation detection

Sandy L. Nguyen, Christos D Malliakas, John A. Peters, Zhifu Liu, Jino Im, Li Dong Zhao, Maria Sebastian, Hosub Jin, Hao Li, Simon Johnsen, Bruce W Wessels, Arthur J Freeman, Mercouri Kanatzidis*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

36 Scopus citations


The chemical concept of lattice hybridization was applied to identify new chalcohalide compounds as candidates for X-ray and γ-ray detection. Per this approach, compound semiconductor materials with high density and wide band gaps can be produced that can absorb and detect hard radiation. Here, we show that the mixed chalcogenide-halide compound Tl 6 SI 4 is a congruently melting, mechanically robust chalcohalide material with strong photoconductivity response and an impressive room-temperature figure of merit. Tl 6 SI 4 crystallizes in the tetragonal P4/mnc space group, with a = 9.1758(13) Å, c = 9.5879(19) Å, V = 807.3(2) Å 3 , and a calculated density of 7.265 g·cm -3 . The new material requires a more simplified crystal growth compared to the leading system Cd 0.9 Zn 0.1 Te, which is the benchmark room-temperature hard radiation detector material. We successfully synthesized Tl 6 SI 4 crystals to produce detector-grade wafers with high resistivity values (∼10 10 Ω·cm) and high-resolution detection of X-ray spectra from an Ag (22 keV) source.

Original languageEnglish (US)
Pages (from-to)2868-2877
Number of pages10
JournalChemistry of Materials
Issue number14
StatePublished - Jul 23 2013


  • chalcogenide
  • crystal growth
  • radiation detection
  • wide-gap semiconductors

ASJC Scopus subject areas

  • Chemistry(all)
  • Chemical Engineering(all)
  • Materials Chemistry

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