Metin Aslan - Academia.edu (original) (raw)
Papers by Metin Aslan
International Journal of Physical Research, 2016
We have performed first principles method to investigate structural and electronic properties of ... more We have performed first principles method to investigate structural and electronic properties of GaAs 1-x N x and GaAs 1-x Bi x ternary semiconductor alloy using Density Functional Theory and pseudo potential method within the Generalized Gradient Approximations and Local Density Approximation. The Zinc-Blende phase is found stable for GaAsN and GaAsBi alloys. In this study we investigate the both bowing parameters changing with Bismuth concentration in GaAsBi and Nitrogen concentration in GaAsN alloys. By using the bowing parameter of GaAsBi and GaAsN alloys we obtained the bandgap energies for all x concentrations (0 < x < 1) and lattice constant of both alloys which are important for wide range device application. For studied materials, lattice parameters and band gap energies are compared with available theoretical and experimental works.
Philosophical Magazine, 2016
Abstract We have performed first-principles method to investigate structural and electronic prope... more Abstract We have performed first-principles method to investigate structural and electronic properties of InNxP1−x ternary semiconductor alloy in full range (0 ≤ x ≤ 1) using density functional theory. We have used modified Becke–Johnson potential to obtain accurate band gap results. From the electronic band structure calculation we have found that InNxP1−x become metal between 47 and 80% of nitrogen concentration. Additional to our band gap calculations, we have also used the band anticrossing model. The band anticrossing model supplies a simple, analytical expression to calculate the physical properties, such as the electronic and optical properties, of III-NxV1−x alloys. The knowledge of the electron density of states is required to understand and clarify some properties of materials such as the band structures, bonding character and dielectric function. In order to have a deeper understanding of these properties of the studied materials, the total and partial density of states has been calculated. Finally, we have calculated the total bowing parameter b of studied alloys, together with three contributions bVD, bCE, and bSR due to volume deformation, different atomic electron negativities and structural relaxation, respectively.
Philosophical Magazine, 2016
Abstract A novel 1,3,4-oxadiazole-substituted benzo[b]triphenylene was synthesized by three-step ... more Abstract A novel 1,3,4-oxadiazole-substituted benzo[b]triphenylene was synthesized by three-step synthetic procedure and OFET device design was successfully designed after theoretical calculations made using Gaussian software. For investigating the field-effect properties of designed organic electronic device, a SiO2 (300 nm) was thermally grown on p-Si wafer at 1000 °C as a dielectric layer and gate, source and drain contacts have been deposited using Au metal with physical vapour deposition. 1,3,4-Oxadiazole-substituted benzo[b]triphenylene was spin coated on the source and drain electrodes of our device, forming organic/inorganic interfaced field-effect transistors. Surface morphology and thin film properties were investigated using AFM. All electrical measurements were done in air ambient. The device showed a typical p-type channel behaviour with increasing negative gate bias voltage values. Our results have surprisingly shown that the saturation regime of this device has high mobility (μFET), excellent on/off ratio (Ion/Ioff), high transconductance (gm) and a small threshold voltage (VTh). The values of μFET, Ion/Ioff, gm and VTh were found as 5.02 cm2/Vs, 0.7 × 103, 5.64 μS/mm and 1.37 V, respectively. These values show that our novel organic material could be a potential candidate for organic electronic device applications in the future.
The European Physical Journal B, 2015
The structural and electronic properties of cubic BxGa1−xAs1−yBiy alloys with bismuth (Bi) concen... more The structural and electronic properties of cubic BxGa1−xAs1−yBiy alloys with bismuth (Bi) concentration of 0.0625, 0.125, 0.1875 and 0.25 are studied with various boron (B) compositions by means of density functional theory (DFT) within the Wu-Cohen (WC) exchange correlation potential based on generalized gradient approximation (GGA). For all studied alloy structures, we have implemented geometric optimization before the volume optimization calculations. The obtained equilibrium lattice constants and band gap of studied quaternary alloys are investigated for the first time in literature. While the lattice constant behavior changes linearly with boron concentration, increasing small amount of bismuth concentration alter the lattice constant nonlinearly. The present calculation shows that the band gap decreases with increasing bismuth concentration and direct band gap semiconductor alloy became an indirect band gap with increasing boron concentration. From the band offset calculation we have shown that increasing B and Bi concentration in host GaAs reduced the valance band offset in a heterostructure formed by GaAs and studied alloys.
Computational Materials Science, 2015
ABSTRACT III-Bi compounds have been extensively studied in recent years because of their wide app... more ABSTRACT III-Bi compounds have been extensively studied in recent years because of their wide applications in optoelectronic devices. Despite the wealth of theoretical works, optical properties of first two members of this family, namely BBi and AlBi, are not completely investigated in the literature. Thus, we have studied electronic and optical properties of these compounds using the density functional theory (DFT) based on full potential linearized augmented plane wave method (FP-LAPW) as implemented in the WIEN2k. We have used the Yukawa Screened-PBE0 (YS-PBE0) hybrid function to calculate structural, electronic and optical properties of BBi and AlBi for the first time in the literature. Our structural and electronic results are compared with other available theoretical studies. Finally, optical parameters of both BBi and AlBi compounds have been investigated by means of our obtained electronic results.
Computational Materials Science, 2014
ABSTRACT a b s t r a c t The physical properties of Boron – group V compounds have been investiga... more ABSTRACT a b s t r a c t The physical properties of Boron – group V compounds have been investigated systematically by using density functional theory, based on the full-potential linearized augmented plane-wave method. Gener-alized gradient approximation is performed to calculate the structural and elastic properties of all studied Boron compounds. We have investigated the phase stability of Boron-V compounds in zinc-blend, rock-salt and wurtzite crystallographic phases. The structural properties such as the equilibrium lattice parameter, bulk modulus and its pressure derivative of Boron-V compounds have been calculated in three phases and compared with other theoretical and experimental works. The elastic properties of the stud-ied compounds are only investigated in the most stable calculated phase. We have obtained Young's modulus, shear modulus, Poisson's ratio, anisotropy factor, Kleinmann parameter, wave velocities and melting temperature by the aid of the calculated elastic constants, which are of great technological importance to Boron related compounds. And, we have also found the Debye temperature of the com-pounds from the average wave velocity. Our results are in reasonable agreement with the available the-oretical and experimental data. Detailed comparisons are made with the results obtained in previous theoretical studies and available measured values. Ó 2013 Elsevier B.V. All rights reserved.
Journal of Alloys and Compounds, 2012
ABSTRACT We have presented structural and electronic properties of binary (GaAs, GaN and InAs), t... more ABSTRACT We have presented structural and electronic properties of binary (GaAs, GaN and InAs), ternary (Ga1−xInxAs and GaAs1−yNy) and quaternary (Ga1−xInxAs1−yNy) semiconductor alloys by using a first-principles pseudopotential technique. The structural and electronic properties of Zinc-Blende phase of these materials have been calculated by using the local density approximation (LDA) of the density-functional theory (DFT). To obtain the lattice parameter and band gap energy of the (GaInAsN) quaternary semiconductor alloy we separately calculated the lattice constant and band gap energies of ternary semiconductor alloys, namely GaAsN and GaInAs. The calculated lattice constant, bulk modulus and the direct band gaps for studied semiconductors showed great parallelism with the previous available theoretical and experimental studies.
International Journal of Physical Research, 2016
We have performed first principles method to investigate structural and electronic properties of ... more We have performed first principles method to investigate structural and electronic properties of GaAs 1-x N x and GaAs 1-x Bi x ternary semiconductor alloy using Density Functional Theory and pseudo potential method within the Generalized Gradient Approximations and Local Density Approximation. The Zinc-Blende phase is found stable for GaAsN and GaAsBi alloys. In this study we investigate the both bowing parameters changing with Bismuth concentration in GaAsBi and Nitrogen concentration in GaAsN alloys. By using the bowing parameter of GaAsBi and GaAsN alloys we obtained the bandgap energies for all x concentrations (0 < x < 1) and lattice constant of both alloys which are important for wide range device application. For studied materials, lattice parameters and band gap energies are compared with available theoretical and experimental works.
Philosophical Magazine, 2016
Abstract We have performed first-principles method to investigate structural and electronic prope... more Abstract We have performed first-principles method to investigate structural and electronic properties of InNxP1−x ternary semiconductor alloy in full range (0 ≤ x ≤ 1) using density functional theory. We have used modified Becke–Johnson potential to obtain accurate band gap results. From the electronic band structure calculation we have found that InNxP1−x become metal between 47 and 80% of nitrogen concentration. Additional to our band gap calculations, we have also used the band anticrossing model. The band anticrossing model supplies a simple, analytical expression to calculate the physical properties, such as the electronic and optical properties, of III-NxV1−x alloys. The knowledge of the electron density of states is required to understand and clarify some properties of materials such as the band structures, bonding character and dielectric function. In order to have a deeper understanding of these properties of the studied materials, the total and partial density of states has been calculated. Finally, we have calculated the total bowing parameter b of studied alloys, together with three contributions bVD, bCE, and bSR due to volume deformation, different atomic electron negativities and structural relaxation, respectively.
Philosophical Magazine, 2016
Abstract A novel 1,3,4-oxadiazole-substituted benzo[b]triphenylene was synthesized by three-step ... more Abstract A novel 1,3,4-oxadiazole-substituted benzo[b]triphenylene was synthesized by three-step synthetic procedure and OFET device design was successfully designed after theoretical calculations made using Gaussian software. For investigating the field-effect properties of designed organic electronic device, a SiO2 (300 nm) was thermally grown on p-Si wafer at 1000 °C as a dielectric layer and gate, source and drain contacts have been deposited using Au metal with physical vapour deposition. 1,3,4-Oxadiazole-substituted benzo[b]triphenylene was spin coated on the source and drain electrodes of our device, forming organic/inorganic interfaced field-effect transistors. Surface morphology and thin film properties were investigated using AFM. All electrical measurements were done in air ambient. The device showed a typical p-type channel behaviour with increasing negative gate bias voltage values. Our results have surprisingly shown that the saturation regime of this device has high mobility (μFET), excellent on/off ratio (Ion/Ioff), high transconductance (gm) and a small threshold voltage (VTh). The values of μFET, Ion/Ioff, gm and VTh were found as 5.02 cm2/Vs, 0.7 × 103, 5.64 μS/mm and 1.37 V, respectively. These values show that our novel organic material could be a potential candidate for organic electronic device applications in the future.
The European Physical Journal B, 2015
The structural and electronic properties of cubic BxGa1−xAs1−yBiy alloys with bismuth (Bi) concen... more The structural and electronic properties of cubic BxGa1−xAs1−yBiy alloys with bismuth (Bi) concentration of 0.0625, 0.125, 0.1875 and 0.25 are studied with various boron (B) compositions by means of density functional theory (DFT) within the Wu-Cohen (WC) exchange correlation potential based on generalized gradient approximation (GGA). For all studied alloy structures, we have implemented geometric optimization before the volume optimization calculations. The obtained equilibrium lattice constants and band gap of studied quaternary alloys are investigated for the first time in literature. While the lattice constant behavior changes linearly with boron concentration, increasing small amount of bismuth concentration alter the lattice constant nonlinearly. The present calculation shows that the band gap decreases with increasing bismuth concentration and direct band gap semiconductor alloy became an indirect band gap with increasing boron concentration. From the band offset calculation we have shown that increasing B and Bi concentration in host GaAs reduced the valance band offset in a heterostructure formed by GaAs and studied alloys.
Computational Materials Science, 2015
ABSTRACT III-Bi compounds have been extensively studied in recent years because of their wide app... more ABSTRACT III-Bi compounds have been extensively studied in recent years because of their wide applications in optoelectronic devices. Despite the wealth of theoretical works, optical properties of first two members of this family, namely BBi and AlBi, are not completely investigated in the literature. Thus, we have studied electronic and optical properties of these compounds using the density functional theory (DFT) based on full potential linearized augmented plane wave method (FP-LAPW) as implemented in the WIEN2k. We have used the Yukawa Screened-PBE0 (YS-PBE0) hybrid function to calculate structural, electronic and optical properties of BBi and AlBi for the first time in the literature. Our structural and electronic results are compared with other available theoretical studies. Finally, optical parameters of both BBi and AlBi compounds have been investigated by means of our obtained electronic results.
Computational Materials Science, 2014
ABSTRACT a b s t r a c t The physical properties of Boron – group V compounds have been investiga... more ABSTRACT a b s t r a c t The physical properties of Boron – group V compounds have been investigated systematically by using density functional theory, based on the full-potential linearized augmented plane-wave method. Gener-alized gradient approximation is performed to calculate the structural and elastic properties of all studied Boron compounds. We have investigated the phase stability of Boron-V compounds in zinc-blend, rock-salt and wurtzite crystallographic phases. The structural properties such as the equilibrium lattice parameter, bulk modulus and its pressure derivative of Boron-V compounds have been calculated in three phases and compared with other theoretical and experimental works. The elastic properties of the stud-ied compounds are only investigated in the most stable calculated phase. We have obtained Young's modulus, shear modulus, Poisson's ratio, anisotropy factor, Kleinmann parameter, wave velocities and melting temperature by the aid of the calculated elastic constants, which are of great technological importance to Boron related compounds. And, we have also found the Debye temperature of the com-pounds from the average wave velocity. Our results are in reasonable agreement with the available the-oretical and experimental data. Detailed comparisons are made with the results obtained in previous theoretical studies and available measured values. Ó 2013 Elsevier B.V. All rights reserved.
Journal of Alloys and Compounds, 2012
ABSTRACT We have presented structural and electronic properties of binary (GaAs, GaN and InAs), t... more ABSTRACT We have presented structural and electronic properties of binary (GaAs, GaN and InAs), ternary (Ga1−xInxAs and GaAs1−yNy) and quaternary (Ga1−xInxAs1−yNy) semiconductor alloys by using a first-principles pseudopotential technique. The structural and electronic properties of Zinc-Blende phase of these materials have been calculated by using the local density approximation (LDA) of the density-functional theory (DFT). To obtain the lattice parameter and band gap energy of the (GaInAsN) quaternary semiconductor alloy we separately calculated the lattice constant and band gap energies of ternary semiconductor alloys, namely GaAsN and GaInAs. The calculated lattice constant, bulk modulus and the direct band gaps for studied semiconductors showed great parallelism with the previous available theoretical and experimental studies.