The surface relaxations, surface energies and electronic structures of BaOand SnO 2-terminated Ba... more The surface relaxations, surface energies and electronic structures of BaOand SnO 2-terminated BaSnO 3 (001) surfaces have been studied by employing the first-principles density functional theory. For both terminations, we find that the upper-layer Ba and Sn atoms move inward, whereas upper-layer O atoms move outward from the surface. Moreover, the largest relaxations are occurred on the first-layer atoms of both terminations. The surface rumpling of BaO-terminated BaSnO 3 (001) is slightly less than that of the SnO 2-terminated BaSnO 3 (001) surface. The surface energies show that both terminated surfaces are energetically stable and favorable. Finally, the surface band gap is slightly decreased for the BaO termination, while it is dramatically decreased for the SnO 2 termination.
Transparent conductive oxides, such as tin dioxide (SnO 2), have recently shown to be promising m... more Transparent conductive oxides, such as tin dioxide (SnO 2), have recently shown to be promising materials for thermoelectric applications. In this work we studied the thermoelectric properties of Fe-, Sb-and Zn-uniformly doping and co-doping SnO 2 , as well as of Sb and Zn planar (or delta)-doped layers in SnO 2 forming oxide superlattices (SLs). Based on the semiclassical Boltzmann transport equations (BTE) in conjunction with ab initio electronic structure calculations, the Seebeck coefficient (S) and figure of merit (ZT) are obtained for these systems, and are compared with available experimental data. The delta doping approach introduces a remarkable modification in the electronic structure of tin dioxide, when compared with the uniform doping, and colossal values for ZT are predicted for the delta-doped oxide SLs. This result is a consequence of the two-dimensional electronic confinement and the strong anisotropy introduced by the doped planes. In comparison with the uniformly doped systems, our predictions reveal a promising use of delta-doped SnO 2 SLs for enhanced S and ZT, which emerge as potential candidates for thermoelectric applications.
Abstract The present work is focused on obtaining sol-gel thin films belonging to ZnO-P 2 O 5 sys... more Abstract The present work is focused on obtaining sol-gel thin films belonging to ZnO-P 2 O 5 system by using zinc acetate dehydrate; diethanol amine and orthophosphoric acid. It was confirmed by scanning electron microscopy that ZnO-P 2 O 5 thin films are homogeneous. The X-ray diffraction patterns indicated that the binary structure system is amorphous. FTIR (Fourier transform infrared spectroscopy) aimed at investigating the structural features of zinc phosphate network; and the synthesized films exhibited the UV transmittance at around 85%with the estimated direct band gap energy of 3.5 eV.
In this study, we synthesized neat and loaded lead phosphate glass (PbO–P2O5) with the inclusion ... more In this study, we synthesized neat and loaded lead phosphate glass (PbO–P2O5) with the inclusion of Cr, Co, Ni, and Zn using an inexpensive sol–gel technique. These composites were then deposited on silica glass substrates. Our objective was to investigate the influence of these fillers on the properties of the glass. The concentrations of the fillers were varied from 0 to 16 wt%, and the resulting thin films were characterized by measuring the absorption coefficient and estimating the optical band gap at room temperature. Additionally, we measured the electrical resistivity of the semiconducting thin films as a function of filler concentrations and temperature. To assess the overall performance of the films, we calculated the figure of merit using the Iles and Soclof approach, considering the DC resistance versus free carrier concentration and absorption coefficient. Interestingly, our results revealed a significant improvement in the figure of merit at specific filler concentratio...
Journal of Superconductivity and Novel Magnetism, 2021
In this paper, the LiMg0.95TM0.05N alloy (TM=Ti, V, and Cr) undergo the Korringa-Kohn-Rostoker fr... more In this paper, the LiMg0.95TM0.05N alloy (TM=Ti, V, and Cr) undergo the Korringa-Kohn-Rostoker framework and “coherent potential approximation” to examine the magnetic and electronic behaviors, based on the MACHIKANEYAMA2002v09 program. In LiMg0.95TM0.05N alloy, the N ions around TM ions form a zinc-blende structure crystal field, which causes the Ti[d], V[d], and Cr[d] orbitals to split into the lower doubly degenerate eg(dx2-y2,dz2) and higher triply degenerate t2g(dxy,dyz,dxz) states. The “electron spin polarization (P)” of TM[d] is around the Fermi energy (Ef) and exhibits the half metallic characteristic, and the ferromagnetic stability is depicted in LiMg0.95TM0.05N. Also, the computed magnetic and the Curie temperature are valuable at room temperature as promised ferromagnetic material. The obtained values are 541.05 and 453.23 K connected to LiMg0.95V0.05N and LiMg0.95Cr0.05N, respectively. For the LiMg0.95TM0.05N alloy, the exchange splitting $$ \left({\Delta }_{\mathrm{Ex}}^{\mathrm{TM}}\right) $$ is larger than the crystal field splitting $$ \left({\Delta }_{\mathrm{CR}}^{\mathrm{TM}}\right) $$ , where $$ {\Delta }_{\mathrm{Ex}}^{\mathrm{Cr}}>{\Delta }_{\mathrm{Ex}}^{\mathrm{V}}>{\Delta }_{\mathrm{Ex}}^{\mathrm{Ti}} $$ and $$ {\Delta }_{\mathrm{CR}}^{\mathrm{Cr}}>{\Delta }_{\mathrm{CR}}^{\mathrm{V}}>{\Delta }_{\mathrm{CR}}^{\mathrm{Ti}} $$ . Also, total spin moment is arranged as follows: $$ {M}_{{\mathrm{LiMg}}_{0.95}{\mathrm{Cr}}_{0.05}\mathrm{N}}^{\mathrm{Total}}>{M}_{{\mathrm{LiMg}}_{0.95}{\mathrm{V}}_{0.05}\mathrm{N}}^{\mathrm{Total}}>{M}_{{\mathrm{LiMg}}_{0.95}{\mathrm{Ti}}_{0.05}\mathrm{N}}^{\mathrm{Total}}. $$
We discuss the fundamental transparent conducting properties of halogens doped SnO 2 rutile syste... more We discuss the fundamental transparent conducting properties of halogens doped SnO 2 rutile systems include the structural, electronic structure, optical and electrical properties. Within this study, we employ the first-principles calculation of the full potential linearized augmented plane wave (FP-LAPW) method based on the density function theory and semiclassical Boltzmann equations. It is found that the halogens substitutional doping cause an expansion of SnO 2 lattice constants and low thermodynamic perturbation. The dopants act as shallow donors by creating impurity states at the bottom of the conduction band that lead to blue-shift in the optical transparency. Moreover, the electrical conductivity of SnO 2 Rutile is significantly improving by halogens doping. In fact, these results could stimulate the future experimental works for elaborating new generations of the transparent conducting oxides in an optimal way. Keywords Transparent conducting oxides Á Ab initio calculations Á SnO 2 rutile Á Semiclasscal Boltzmann equations Á Optical properties Á Electrical properties & A. Slassi
Abstract By means of first-Principe method within TB-mBJ approach and Boltzmann transport equatio... more Abstract By means of first-Principe method within TB-mBJ approach and Boltzmann transport equations, the electronic structure, optical and electrical properties of zinc oxide doped with Iron are investigated. Both calculated band gap and lattice parameters of pure ZnO are found to be in reasonable agreement with the experimental measurements. Furthermore, the doping ZnO with Fe leads to the appearance of some deep impurity levels in the band gap arisen from Fe-3d states. Indeed, these deep level donors enhance the infrared and visible-light absorption. Besides, we notice that the electrical conductivity is enhanced while the carrier mobility is decreased after Fe doping.
The main purpose of this study is to elaborate anticorrosive coatings for the welded steel 316L, ... more The main purpose of this study is to elaborate anticorrosive coatings for the welded steel 316L, since this later is widely used in industrial field. Hence, within this work we have studied the electrochemical behaviour of different zones of the welded steel 316 in 1 M HCl media. The macrography study of the welded steel has revealed the different areas with a good contrast. We have stated three different zones, namely; melted zone (MZ), heat affected zone (HAZ) and base metal zone (BM). Impedance studies on welded steel 316L were conducted in 1 M HCl solution, coating of Epoxy/Alumina composite was applied on different zones, in order to reveal the anti-corrosion efficiency in each zone. Scanning electron microscopy (SEM) analysis was undertaken in order to check how far the used coating in such aggressive media protects the studied zones and these findings were assessed by water contact angle measurements. The choice of this coating is based on the cost and the safety. We conclude...
Recently, the rise of two dimensional amorphous nanostructured thin films have ignited a big inte... more Recently, the rise of two dimensional amorphous nanostructured thin films have ignited a big interest because of their intriguingly isotropic structural and physical properties leading to potential applications in the nano-optoelectronics. However, according to literature, most of optoelectronic properties are investigated on chalcogenides related heterostructures. This has motivated the present work aiming to provide a new platform for the fabrication, examination of the properties and the applications of 2D nanostructured thin films based on epoxy/silicone blend. Thin films of Epoxy/Silicone loaded with nitrogen doped carbon nanotubes (N-CNTs) were prepared by sol-gel method and deposited on Indium Tin Oxide (ITO) glass substrates at room temperature. Further examination of optical properties aimed the investigation of optical pseudo-gap and Urbach energy and enabled the determination of processed films thickness based on Manifacier and Swanepol method. The results indicated that ...
In this study, we have investigated the surface analysis and optoelectronic properties on the syn... more In this study, we have investigated the surface analysis and optoelectronic properties on the synthesis of N-CNT/TiO2 composites thin films, using sol gel method for a dye synthetized solar cell (DSSC) which is found to be simple and economical route. The titanium dioxide based solar cells are an exciting photovoltaic candidate; they are promising for the realization of large area devices. That can be synthetized by room temperature solution processing, with high photoactive performance. In the present work, we stated comparable efficiencies by directing our investigation on obtaining Sol Gel thin films based on N-CNT/TiO2, by dispersing nitrogen (N) doped carbon nanotubes (N-CNTs) powders in titanium tetraisopropoxyde (TTIP). The samples were assessed in terms of optical properties, using UV—visible absorption spectroscopic techniques. After careful analysis of the results, we have concluded that the mentioned route is good and more efficient in terms of optoelectronic properties. ...
ZnO and TiO2 are direct wide band gap semiconductors with intriguing properties. A wide range of ... more ZnO and TiO2 are direct wide band gap semiconductors with intriguing properties. A wide range of applications makes it one of the most studied materials in the past decade, particularly when elaborated as nanostructures. In this work, we focus on synthesis of CNTs modified ZnO and TiO2 thin films using sol-gel method. The morphological and optical characterizations of the based ZnO and TiO2 films were carried out using scanning and transmission electron microscopy (SEM and TEM), XRD and UV spectroscopy. Electrical properties of the deposited ZnO/CNTs and CNTs /TiO2 were studied using I-V measurements at room temperature in metal/semiconductor/metal configuration, by the use of an array of metallic micro-electrodes deposited on the surface of the elaborated thin films. This allows determining qualitatively the electrical conductivity of thin films and the different parameters of the Schottky junction between the composites nano-films and the substrate. This study is necessary for fut...
The goal of this paper is to study the effect of the small amount of molybdenum-doped [Formula: s... more The goal of this paper is to study the effect of the small amount of molybdenum-doped [Formula: see text] on the magnetism behavior of that system. We utilized the density functional theory (DFT): DFT framework within MACHIKANEYAMA2002V09 package based on Coherent Potential Approximation (CPA). Inducing the magnetism in the diluted magnetic semiconductors (DMS) with a low dopant concentration at adequate room-temperature is a challenge, so, we restricted the Mo impurity at 2%. In addition, the small amount of Mo-doped [Formula: see text] is found optimal in many studies related to other fields. The ferromagnetic stability is observed in [Formula: see text] system, since the [Formula: see text] state of Mo element is found around the Fermi level and is 100% spin polarized, the half-metallic characteristic is useful in magnetoelectronic applications. Within the mean-field approximation (MFA) we predict the Curie temperature, as an obtained value, the [Formula: see text] K, consequentl...
The surface relaxations, surface energies and electronic structures of BaOand SnO 2-terminated Ba... more The surface relaxations, surface energies and electronic structures of BaOand SnO 2-terminated BaSnO 3 (001) surfaces have been studied by employing the first-principles density functional theory. For both terminations, we find that the upper-layer Ba and Sn atoms move inward, whereas upper-layer O atoms move outward from the surface. Moreover, the largest relaxations are occurred on the first-layer atoms of both terminations. The surface rumpling of BaO-terminated BaSnO 3 (001) is slightly less than that of the SnO 2-terminated BaSnO 3 (001) surface. The surface energies show that both terminated surfaces are energetically stable and favorable. Finally, the surface band gap is slightly decreased for the BaO termination, while it is dramatically decreased for the SnO 2 termination.
Transparent conductive oxides, such as tin dioxide (SnO 2), have recently shown to be promising m... more Transparent conductive oxides, such as tin dioxide (SnO 2), have recently shown to be promising materials for thermoelectric applications. In this work we studied the thermoelectric properties of Fe-, Sb-and Zn-uniformly doping and co-doping SnO 2 , as well as of Sb and Zn planar (or delta)-doped layers in SnO 2 forming oxide superlattices (SLs). Based on the semiclassical Boltzmann transport equations (BTE) in conjunction with ab initio electronic structure calculations, the Seebeck coefficient (S) and figure of merit (ZT) are obtained for these systems, and are compared with available experimental data. The delta doping approach introduces a remarkable modification in the electronic structure of tin dioxide, when compared with the uniform doping, and colossal values for ZT are predicted for the delta-doped oxide SLs. This result is a consequence of the two-dimensional electronic confinement and the strong anisotropy introduced by the doped planes. In comparison with the uniformly doped systems, our predictions reveal a promising use of delta-doped SnO 2 SLs for enhanced S and ZT, which emerge as potential candidates for thermoelectric applications.
Abstract The present work is focused on obtaining sol-gel thin films belonging to ZnO-P 2 O 5 sys... more Abstract The present work is focused on obtaining sol-gel thin films belonging to ZnO-P 2 O 5 system by using zinc acetate dehydrate; diethanol amine and orthophosphoric acid. It was confirmed by scanning electron microscopy that ZnO-P 2 O 5 thin films are homogeneous. The X-ray diffraction patterns indicated that the binary structure system is amorphous. FTIR (Fourier transform infrared spectroscopy) aimed at investigating the structural features of zinc phosphate network; and the synthesized films exhibited the UV transmittance at around 85%with the estimated direct band gap energy of 3.5 eV.
In this study, we synthesized neat and loaded lead phosphate glass (PbO–P2O5) with the inclusion ... more In this study, we synthesized neat and loaded lead phosphate glass (PbO–P2O5) with the inclusion of Cr, Co, Ni, and Zn using an inexpensive sol–gel technique. These composites were then deposited on silica glass substrates. Our objective was to investigate the influence of these fillers on the properties of the glass. The concentrations of the fillers were varied from 0 to 16 wt%, and the resulting thin films were characterized by measuring the absorption coefficient and estimating the optical band gap at room temperature. Additionally, we measured the electrical resistivity of the semiconducting thin films as a function of filler concentrations and temperature. To assess the overall performance of the films, we calculated the figure of merit using the Iles and Soclof approach, considering the DC resistance versus free carrier concentration and absorption coefficient. Interestingly, our results revealed a significant improvement in the figure of merit at specific filler concentratio...
Journal of Superconductivity and Novel Magnetism, 2021
In this paper, the LiMg0.95TM0.05N alloy (TM=Ti, V, and Cr) undergo the Korringa-Kohn-Rostoker fr... more In this paper, the LiMg0.95TM0.05N alloy (TM=Ti, V, and Cr) undergo the Korringa-Kohn-Rostoker framework and “coherent potential approximation” to examine the magnetic and electronic behaviors, based on the MACHIKANEYAMA2002v09 program. In LiMg0.95TM0.05N alloy, the N ions around TM ions form a zinc-blende structure crystal field, which causes the Ti[d], V[d], and Cr[d] orbitals to split into the lower doubly degenerate eg(dx2-y2,dz2) and higher triply degenerate t2g(dxy,dyz,dxz) states. The “electron spin polarization (P)” of TM[d] is around the Fermi energy (Ef) and exhibits the half metallic characteristic, and the ferromagnetic stability is depicted in LiMg0.95TM0.05N. Also, the computed magnetic and the Curie temperature are valuable at room temperature as promised ferromagnetic material. The obtained values are 541.05 and 453.23 K connected to LiMg0.95V0.05N and LiMg0.95Cr0.05N, respectively. For the LiMg0.95TM0.05N alloy, the exchange splitting $$ \left({\Delta }_{\mathrm{Ex}}^{\mathrm{TM}}\right) $$ is larger than the crystal field splitting $$ \left({\Delta }_{\mathrm{CR}}^{\mathrm{TM}}\right) $$ , where $$ {\Delta }_{\mathrm{Ex}}^{\mathrm{Cr}}>{\Delta }_{\mathrm{Ex}}^{\mathrm{V}}>{\Delta }_{\mathrm{Ex}}^{\mathrm{Ti}} $$ and $$ {\Delta }_{\mathrm{CR}}^{\mathrm{Cr}}>{\Delta }_{\mathrm{CR}}^{\mathrm{V}}>{\Delta }_{\mathrm{CR}}^{\mathrm{Ti}} $$ . Also, total spin moment is arranged as follows: $$ {M}_{{\mathrm{LiMg}}_{0.95}{\mathrm{Cr}}_{0.05}\mathrm{N}}^{\mathrm{Total}}>{M}_{{\mathrm{LiMg}}_{0.95}{\mathrm{V}}_{0.05}\mathrm{N}}^{\mathrm{Total}}>{M}_{{\mathrm{LiMg}}_{0.95}{\mathrm{Ti}}_{0.05}\mathrm{N}}^{\mathrm{Total}}. $$
We discuss the fundamental transparent conducting properties of halogens doped SnO 2 rutile syste... more We discuss the fundamental transparent conducting properties of halogens doped SnO 2 rutile systems include the structural, electronic structure, optical and electrical properties. Within this study, we employ the first-principles calculation of the full potential linearized augmented plane wave (FP-LAPW) method based on the density function theory and semiclassical Boltzmann equations. It is found that the halogens substitutional doping cause an expansion of SnO 2 lattice constants and low thermodynamic perturbation. The dopants act as shallow donors by creating impurity states at the bottom of the conduction band that lead to blue-shift in the optical transparency. Moreover, the electrical conductivity of SnO 2 Rutile is significantly improving by halogens doping. In fact, these results could stimulate the future experimental works for elaborating new generations of the transparent conducting oxides in an optimal way. Keywords Transparent conducting oxides Á Ab initio calculations Á SnO 2 rutile Á Semiclasscal Boltzmann equations Á Optical properties Á Electrical properties & A. Slassi
Abstract By means of first-Principe method within TB-mBJ approach and Boltzmann transport equatio... more Abstract By means of first-Principe method within TB-mBJ approach and Boltzmann transport equations, the electronic structure, optical and electrical properties of zinc oxide doped with Iron are investigated. Both calculated band gap and lattice parameters of pure ZnO are found to be in reasonable agreement with the experimental measurements. Furthermore, the doping ZnO with Fe leads to the appearance of some deep impurity levels in the band gap arisen from Fe-3d states. Indeed, these deep level donors enhance the infrared and visible-light absorption. Besides, we notice that the electrical conductivity is enhanced while the carrier mobility is decreased after Fe doping.
The main purpose of this study is to elaborate anticorrosive coatings for the welded steel 316L, ... more The main purpose of this study is to elaborate anticorrosive coatings for the welded steel 316L, since this later is widely used in industrial field. Hence, within this work we have studied the electrochemical behaviour of different zones of the welded steel 316 in 1 M HCl media. The macrography study of the welded steel has revealed the different areas with a good contrast. We have stated three different zones, namely; melted zone (MZ), heat affected zone (HAZ) and base metal zone (BM). Impedance studies on welded steel 316L were conducted in 1 M HCl solution, coating of Epoxy/Alumina composite was applied on different zones, in order to reveal the anti-corrosion efficiency in each zone. Scanning electron microscopy (SEM) analysis was undertaken in order to check how far the used coating in such aggressive media protects the studied zones and these findings were assessed by water contact angle measurements. The choice of this coating is based on the cost and the safety. We conclude...
Recently, the rise of two dimensional amorphous nanostructured thin films have ignited a big inte... more Recently, the rise of two dimensional amorphous nanostructured thin films have ignited a big interest because of their intriguingly isotropic structural and physical properties leading to potential applications in the nano-optoelectronics. However, according to literature, most of optoelectronic properties are investigated on chalcogenides related heterostructures. This has motivated the present work aiming to provide a new platform for the fabrication, examination of the properties and the applications of 2D nanostructured thin films based on epoxy/silicone blend. Thin films of Epoxy/Silicone loaded with nitrogen doped carbon nanotubes (N-CNTs) were prepared by sol-gel method and deposited on Indium Tin Oxide (ITO) glass substrates at room temperature. Further examination of optical properties aimed the investigation of optical pseudo-gap and Urbach energy and enabled the determination of processed films thickness based on Manifacier and Swanepol method. The results indicated that ...
In this study, we have investigated the surface analysis and optoelectronic properties on the syn... more In this study, we have investigated the surface analysis and optoelectronic properties on the synthesis of N-CNT/TiO2 composites thin films, using sol gel method for a dye synthetized solar cell (DSSC) which is found to be simple and economical route. The titanium dioxide based solar cells are an exciting photovoltaic candidate; they are promising for the realization of large area devices. That can be synthetized by room temperature solution processing, with high photoactive performance. In the present work, we stated comparable efficiencies by directing our investigation on obtaining Sol Gel thin films based on N-CNT/TiO2, by dispersing nitrogen (N) doped carbon nanotubes (N-CNTs) powders in titanium tetraisopropoxyde (TTIP). The samples were assessed in terms of optical properties, using UV—visible absorption spectroscopic techniques. After careful analysis of the results, we have concluded that the mentioned route is good and more efficient in terms of optoelectronic properties. ...
ZnO and TiO2 are direct wide band gap semiconductors with intriguing properties. A wide range of ... more ZnO and TiO2 are direct wide band gap semiconductors with intriguing properties. A wide range of applications makes it one of the most studied materials in the past decade, particularly when elaborated as nanostructures. In this work, we focus on synthesis of CNTs modified ZnO and TiO2 thin films using sol-gel method. The morphological and optical characterizations of the based ZnO and TiO2 films were carried out using scanning and transmission electron microscopy (SEM and TEM), XRD and UV spectroscopy. Electrical properties of the deposited ZnO/CNTs and CNTs /TiO2 were studied using I-V measurements at room temperature in metal/semiconductor/metal configuration, by the use of an array of metallic micro-electrodes deposited on the surface of the elaborated thin films. This allows determining qualitatively the electrical conductivity of thin films and the different parameters of the Schottky junction between the composites nano-films and the substrate. This study is necessary for fut...
The goal of this paper is to study the effect of the small amount of molybdenum-doped [Formula: s... more The goal of this paper is to study the effect of the small amount of molybdenum-doped [Formula: see text] on the magnetism behavior of that system. We utilized the density functional theory (DFT): DFT framework within MACHIKANEYAMA2002V09 package based on Coherent Potential Approximation (CPA). Inducing the magnetism in the diluted magnetic semiconductors (DMS) with a low dopant concentration at adequate room-temperature is a challenge, so, we restricted the Mo impurity at 2%. In addition, the small amount of Mo-doped [Formula: see text] is found optimal in many studies related to other fields. The ferromagnetic stability is observed in [Formula: see text] system, since the [Formula: see text] state of Mo element is found around the Fermi level and is 100% spin polarized, the half-metallic characteristic is useful in magnetoelectronic applications. Within the mean-field approximation (MFA) we predict the Curie temperature, as an obtained value, the [Formula: see text] K, consequentl...
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