On the electronic nature of silicon and germanium based oxynitrides and their related mechanical, optical and vibrational properties as obtained from DFT and DFPT

Souraya Goumri-Said; Nawel Kanoun-Bouayed; Ali H. Reshak; Mohammed Benali Kanoun

doi:10.1016/j.commatsci.2011.09.021

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On the electronic nature of silicon and germanium based oxynitrides and their related mechanical, optical and vibrational properties as obtained from DFT and DFPT

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Peer reviewed

On the electronic nature of silicon and germanium based oxynitrides and their related mechanical, optical and vibrational properties as obtained from DFT and DFPT

Souraya Goumri-Said, Nawel Kanoun-Bouayed, Ali H. Reshak and Mohammed Benali Kanoun

Computational materials science, Vol.53(1), pp.158-168

01/02/2012

DOI: https://doi.org/10.1016/j.commatsci.2011.09.021

Abstract

DFT and DFPT methods

Elastic constants

Optical and electronic properties

Phonons

Thermodynamic properties

[Display omitted] ► Oxynitrides electronic structure is provided using FP-(L)APW+lo method. ► The present calculation shows a good agreement with experiments and theoretical data. ► PW-PP and DFPT methods are employed to calculate the elastic properties and phonons. ► Si 2N 2O and Ge 2N 2O compounds are mechanically and dynamically stables. ► Elastic constants are reporte, the thermodynamic properties are deduced from phonons. Electronic structure, bonding and optical properties of the orthorhombic oxynitrides Si 2N 2O and Ge 2N 2O are studied using the density function theory as implemented in pseudo-potential plane wave and full-potential (linearized) augmented plane wave plus local orbitals methods. Generalized gradient approximation is employed in order to determine the band gap energy. Indeed, the Si 2N 2O exhibits a large direct gap whereas Ge 2N 2O have an indirect one. Bonding is analyzed via the charge densities and Mulliken population, where the role of oxygen is investigated. The analysis of the elastic constants show the mechanical stability of both oxynitrides. Their bulk and shear modulus are slightly smaller than those reported on nitrides semiconductors due to the oxygen presence. The optical properties, namely the dielectric function, optical reflectivity, refractive index and electron energy loss, are reported for radiation up to 30 eV. The phonon dispersion relation, zone-center optical mode frequency, density of phonon states are calculated using the density functional perturbed theory. Thermodynamic properties of Si 2N 2O and Ge 2N 2O, such as heat capacity and Debye temperature, are given for reference. Our study suggests that Si 2N 2O and Ge 2N 2O could be a promising potential materials for applications in the microelectronics and optoelectronics areas of research.

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Title: On the electronic nature of silicon and germanium based oxynitrides and their related mechanical, optical and vibrational properties as obtained from DFT and DFPT
Creators - without role: Souraya Goumri-Said - King Abdullah University of Science and Technology
Nawel Kanoun-Bouayed - Equipe:PES, LPT, Université de Tlemcen, Algeria
Ali H. Reshak - Institute of Physical Biology, South Bohemia University, Nove Hrady 37333, Czech Republic
Mohammed Benali Kanoun - King Abdullah University of Science and Technology
Publication Details: Computational materials science, Vol.53(1), pp.158-168
Publisher: Elsevier B.V
Identifiers: 9919675208331
Academic Unit: King Faisal University; Prince Sultan University
Language: English
Resource Type: Journal article