Abstract

BENMEKIDECHE, N. et al. Structural, electronic and optical properties of the wide band gap semiconductors KGaQ₂ (Q = S, Se) and of AGaTe₂ (A = K, Cs). Rev. mex. fis. [online]. 2022, vol.68, n.6.  Epub July 31, 2023. ISSN 0035-001X.  https://doi.org/10.31349/revmexfis.68.061003.

In this paper, we studied the structural, electronic and some optical properties of KGaQ2 (Q = S, Se) and AGaTe2 (A = K, Cs) crystals using the pseudopotential plane-wave (PP-PW) method based on density functional theory (DFT), the generalized gradient approximation (GGA) parameterized by Perdew-Burke-Ernzerhof (GGA-PBE) is used for the exchange-correlation (XC) potential. We also use the hybrid density functional (HSE06) to study the electronic structures of these materials. Our results for the equilibrium lattice constants (a, b and c), angle β are in good agreement with experiment data. The electronic structure calculation suggested that crystals are direct-gap semiconductors, employing both the Perdew-Burke-Ernzerhof (PBE) and the hybrid (HSE06) functionals. We note that the hybrid density functional improved the value of band gap, and that the studied compounds are semiconductors with wide band-gaps. We have also predicted the optical properties; the refractive index, the reflection coefficient and dielectric constant on high frequencies.

Keywords : Density functional theory; GGA-PBE; HSE06; KGaQ₂ (Q = S, Se); AGaTe₂ (A = K, Cs); Structural properties; Electronic properties; Optical constants.

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