University Sétif 1 FERHAT ABBAS Faculty of Sciences
Détail de l'auteur
Auteur Loubna Debache |
Documents disponibles écrits par cet auteur
Ajouter le résultat dans votre panier Affiner la recherche
Study of Fundamental Physical Properties of Some Ternary Nitride-Based Compounds (Ca5Si2N6 and Sr5Ge2N6) / Loubna Debache
Titre : Study of Fundamental Physical Properties of Some Ternary Nitride-Based Compounds (Ca5Si2N6 and Sr5Ge2N6) Type de document : texte imprimé Auteurs : Loubna Debache ; Youcef Medkour, Directeur de thèse Editeur : Sétif:UFA1 Année de publication : 2024 Importance : 1 vol (88 f .) Format : 29 cm Catégories : Thèses & Mémoires:Physique Mots-clés : Ternary nitrides Density functional theory GGA-PBEsol TB-mBJ Elastic
properties Electronic band structure Optical properties Transport properties Thermodynamic
propertiesIndex. décimale : 530 Physique Résumé : Our work consists in studying the structural, elastic, electronic, optical, thermoelectric
and thermodynamic properties of the ternary nitrides Ca5Si2N6 and Sr5Ge2N6, using the
density functional theory (DFT) within the GGA-PBEsol and TB-mBJ approaches. The
theoretically predicted lattice parameters constants are consistent with the available
experimental results. According to the estimated cohesive energy, formation enthalpy and
Born-Huang stability criterion, the examined compounds are thermodynamically and
mechanically stable. Findings on elastic properties suggest that both nitrides are ductile in
nature with significant elastic anisotropy. Using the TB-mBJ electronic band structure, these
nitrides were found to be semiconductors with a direct band gap (V-V) of 3.55 eV for
Ca5Si2N6 and indirect band gap (V-Γ) of 3.15eV for Sr5Ge2N6. The nitridosilicate compound
can be used as a phosphor material because the band gap and Deby temperature values are
within the recommended range. Substitution with heavier cations leads to narrowing the Eg
value and reducing the Ï´D(K) value. Even that, this material is still useful for other optical
applications. The computed optical functions show a modest static dielectric, a notable optical
anisotropy and a strong absorptivity of electromagnetic waves in the ultraviolet range,
indicating that the title compounds are suitable for UV-optoelectronic applications.
Furthermore, transport properties, including Seebeck coefficient, electrical conductivity,
thermal conductivity, power factor and figure of merit have been studied employing classical
BoltzTrap software. The large figure of merit (ZT) values of these ternary nitrides, suggests
their potential use in thermoelectric devices, especially at low and room temperature. Using
Debye's quasi-harmonic model, we explored the thermodynamic properties of Ca5Si2N6 and
Sr5Ge2N6 under the effect of temperature and pressure such as: the modulus of compressibility
B, coefficient of thermal expansion α, heat capacity at constant volume CV, heat capacity at
constant pressure CP and the Debye temperature Ï´D(K)Côte titre : DPH/0298 En ligne : http://dspace.univ-setif.dz:8888/jspui/retrieve/8476/2309.pdf Format de la ressource électronique : Study of Fundamental Physical Properties of Some Ternary Nitride-Based Compounds (Ca5Si2N6 and Sr5Ge2N6) [texte imprimé] / Loubna Debache ; Youcef Medkour, Directeur de thèse . - [S.l.] : Sétif:UFA1, 2024 . - 1 vol (88 f .) ; 29 cm.
Catégories : Thèses & Mémoires:Physique Mots-clés : Ternary nitrides Density functional theory GGA-PBEsol TB-mBJ Elastic
properties Electronic band structure Optical properties Transport properties Thermodynamic
propertiesIndex. décimale : 530 Physique Résumé : Our work consists in studying the structural, elastic, electronic, optical, thermoelectric
and thermodynamic properties of the ternary nitrides Ca5Si2N6 and Sr5Ge2N6, using the
density functional theory (DFT) within the GGA-PBEsol and TB-mBJ approaches. The
theoretically predicted lattice parameters constants are consistent with the available
experimental results. According to the estimated cohesive energy, formation enthalpy and
Born-Huang stability criterion, the examined compounds are thermodynamically and
mechanically stable. Findings on elastic properties suggest that both nitrides are ductile in
nature with significant elastic anisotropy. Using the TB-mBJ electronic band structure, these
nitrides were found to be semiconductors with a direct band gap (V-V) of 3.55 eV for
Ca5Si2N6 and indirect band gap (V-Γ) of 3.15eV for Sr5Ge2N6. The nitridosilicate compound
can be used as a phosphor material because the band gap and Deby temperature values are
within the recommended range. Substitution with heavier cations leads to narrowing the Eg
value and reducing the Ï´D(K) value. Even that, this material is still useful for other optical
applications. The computed optical functions show a modest static dielectric, a notable optical
anisotropy and a strong absorptivity of electromagnetic waves in the ultraviolet range,
indicating that the title compounds are suitable for UV-optoelectronic applications.
Furthermore, transport properties, including Seebeck coefficient, electrical conductivity,
thermal conductivity, power factor and figure of merit have been studied employing classical
BoltzTrap software. The large figure of merit (ZT) values of these ternary nitrides, suggests
their potential use in thermoelectric devices, especially at low and room temperature. Using
Debye's quasi-harmonic model, we explored the thermodynamic properties of Ca5Si2N6 and
Sr5Ge2N6 under the effect of temperature and pressure such as: the modulus of compressibility
B, coefficient of thermal expansion α, heat capacity at constant volume CV, heat capacity at
constant pressure CP and the Debye temperature Ï´D(K)Côte titre : DPH/0298 En ligne : http://dspace.univ-setif.dz:8888/jspui/retrieve/8476/2309.pdf Format de la ressource électronique : Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité DPH/0298 DPH/0298 Thèse Bibliothéque des sciences Anglais Disponible
Disponible