Manifestation of Point Defects in the Electronic Structure of Hg3Te2Cl2 Crystals

Authors

  • O. V. Bokotey Faculty of Physics, Uzhhorod National University
  • V. V. Vakulchak Faculty of Physics, Uzhhorod National University
  • A. A. Bokotey Faculty of Physics, Uzhhorod National University
  • I. I. Nebola Faculty of Physics, Uzhhorod National University

DOI:

https://doi.org/10.15407/ujpe61.10.0901

Keywords:

band structure, point defects, gap, absorption edge, optical transitions

Abstract

Within the score of the density functional theory, we investigate the impact of point defects on the electronic structure of Hg3Te2Cl2 crystals, by using the supercell model [2×2×1]. The ab initio calculations for defect-free and defective Hg3Te2Cl2 crystals in the LDA approximation are performed for the first time, by using the quantum-chemical software package SIESTA. The studied crystal possesses an indirect band gap. According to the analysis of the obtained data, the indirect gap is equal to 2.628 eV, while the direct gap is 2.714 eV. The influence of vacancy defects on the conductive and optical properties of Hg3Te2Cl2 crystals is discussed in detail. The tellurium and chlorine vacancy defect states indicate the presence of additional energy levels below the bottom of the conduction band edge. We have shown that only tellurium vacancies produce the additional energy levels in a vicinity of the valence band maximum. It is found that the presence of point defects in Hg3Te2Cl2 changes the direction of optical transitions. Therefore, the defective crystal is a direct gap semiconductor. The satisfactory agreement with the experimental data is obtained.

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Published

2019-01-04

How to Cite

Bokotey, O. V., Vakulchak, V. V., Bokotey, A. A., & Nebola, I. I. (2019). Manifestation of Point Defects in the Electronic Structure of Hg3Te2Cl2 Crystals. Ukrainian Journal of Physics, 61(10), 901. https://doi.org/10.15407/ujpe61.10.0901

Issue

Section

Solid matter