Stoichiometric Effects on the Photoelectric Properties of LiInSe2 Crystals for Neutron Detection

Lijian Guo, Yadong Xu, Hongjian Zheng, Wangqi Xue, Jiangpeng Dong, Binbin Zhang, Yihui He, Gangqiang Zha, Duck Young Chung, Wanqi Jie, Mercouri G Kanatzidis

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Abstract

6LiInSe2 is a promising semiconductor candidate for thermal neutron detection due to its large capture cross-section. However, the charge collection efficiency is still insufficient for high resolution for the grown-in defects induced by the stoichiometric deviation. In this work, we report photoelectric properties of stoichiometric LiInSe2 crystal boules up to 70 mm in length and 20 mm in diameter grown by the vertical Bridgman method. Inductively coupled plasma measurements demonstrate that the ratio of Li, In, and Se of the as-grown crystal is very close to 1:1:2, which is optimized by low temperature synthesis processing. The obtained single crystals display high bulk resistivity in the range of 1011-1012 Ω·cm and a direct band gap of 2.01-2.83 eV with a changeable color from red to yellow. The electronic structure of LiInSe2 was studied using first-principles density functional theory calculations, which predicts that the antisite defects of InLi and LiIn are the dominant factor for the different crystal colors observed. The stoichiometric LiInSe2 crystal gives an improved energy resolution, for a semiconductor detector when illuminated with a 241Am@5.48 MeV α source, of 23.3%. The electron mobility-lifetime product (μτ) is ∼2.5 × 10-5 cm2 V-1.

Original languageEnglish
Pages (from-to)2864-2870
Number of pages7
JournalCrystal Growth and Design
Volume18
Issue number5
DOIs
Publication statusPublished - May 2 2018

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ASJC Scopus subject areas

  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics

Cite this

Guo, L., Xu, Y., Zheng, H., Xue, W., Dong, J., Zhang, B., He, Y., Zha, G., Chung, D. Y., Jie, W., & Kanatzidis, M. G. (2018). Stoichiometric Effects on the Photoelectric Properties of LiInSe2 Crystals for Neutron Detection. Crystal Growth and Design, 18(5), 2864-2870. https://doi.org/10.1021/acs.cgd.7b01705