Cu-Doped ZnO Electronic Structure and Optical Properties Studied by First-Principles Calculations and Experiments

The band structure, the density of states and optical absorption properties of Cu-doped ZnO were studied by the first-principles generalized gradient approximation plane-wave pseudopotential method based on density functional theory. For the Zn1-xCuxO (x = 0, x = 0.0278, x = 0.0417) original structure, geometric optimization and energy calculations were performed and compared with experimental results. With increasing Cu concentration, the band gap of the Zn1-xCuxO decreased due to the shift of the conduction band. Since the impurity level was introduced after Cu doping, the conduction band was moved downwards. Additionally, it was shown that the insertion of a Cu atom leads to a red shift of the optical absorption edge, which was consistent with the experimental results.

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Effect of Yb Concentration on the Structural, Magnetic and Optoelectronic Properties of Yb Doped ZnO: First Principles Calculation

10.21203/rs.3.rs-877060/v1 ◽

2021 ◽

Author(s):

Mohamed Achehboune ◽

Mohammed Khenfouch ◽

Issam Boukhoubza ◽

Issam Derkaoui ◽

Bakang Moses Mothudi ◽

...

Keyword(s):

Band Gap ◽

Conduction Band ◽

Density Functional ◽

Blue Shift ◽

First Principles Calculation ◽

Theoretical Research ◽

Generalized Gradient ◽

Functional Theory ◽

Doped Zno ◽

Good Agreement

Abstract Density functional theory-based investigation of the electronic, magnetic, and optical characteristics in pure and ytterbium (Yb) doped ZnO has been carried out by the plane-wave pseudopotential technique with generalized gradient approximation. The calculated lattice parameters and band gap of pure ZnO are in good agreement with the experimental results. The energy band-gap increases with the increase of Yb concentration. The Fermi level moves upward into the conduction band after doping with Yb, which shows the properties of an n-type se miconductor. New defects were created in the band-gap near the conduction band attributed to the Yb-4f states. The magnetic properties of ZnO were found to be affected by Yb doping; ferromagnetic property was observed for 4.17% Yb due to spin polarization of Yb-4f electrons. The calculated optical properties imply that Yb doped causes a blue shift of the absorption peaks, significantly enhances the absorption of the visible light, and the blue shift of the reflectivity spectrum was observed. Besides, a better transmittance of approximately 88% was observed for 4.17% Yb doped ZnO system. The refractive index and the extinction coefficient were observed to decrease as the Yb dopant concentration increased. As a result, we believe that our findings will be useful in understanding the doping impact in ZnO and will motivate further theoretical research.

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Enhanced optical and thermoelectric properties of ZnO by tin and fluorine codoping: First-principles DFT calculations

International Journal of Computational Materials Science and Engineering ◽

10.1142/s204768412050013x ◽

2020 ◽

pp. 2050013

Author(s):

K. Djillali ◽

M. Mana ◽

R. Baghdad ◽

A. Labdelli ◽

A. Nacef ◽

...

Keyword(s):

Electrical Conductivity ◽

Thermodynamic Properties ◽

Optical Absorption ◽

First Principles ◽

Density Functional ◽

Visible Range ◽

Degenerate Semiconductor ◽

Absorption Coefficients ◽

Maximum Value ◽

Doped Zno

Ab initio density functional calculations of the structural, optoelectronic, thermoelectric and thermodynamic properties of ZnO codoped with tin and fluorine with possible application as Transparent Conductive Oxides (TCO’s), are reported in this work. This study shows that incorporation of Sn and F into the ZnO matrix converts it to a degenerate semiconductor. The calculated optical absorption coefficients show that the four compounds ZnO, Sn:ZnO, F:ZnO and Sn:F:ZnO have transparent properties in the visible range. At 900[Formula: see text]K, the Seebeck coefficient of Sn:F:ZnO is greatly improved with respect to the undoped ZnO. A maximum electrical conductivity value of [Formula: see text]S cm[Formula: see text]s[Formula: see text] is predicted for Sn-doped ZnO. ZT increases with temperature to a maximum value of 0.13 at 900[Formula: see text]K for tin and fluorine codoped ZnO.

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First-Principles Calculations of the Electronic Structure and Optical Properties of Yttrium-Doped ZnO Monolayer with Vacancy

Materials ◽

10.3390/ma13030724 ◽

2020 ◽

Vol 13 (3) ◽

pp. 724

Author(s):

Qian Wu ◽

Ping Wang ◽

Yan Liu ◽

Han Yang ◽

Jingsi Cheng ◽

...

Keyword(s):

Oxygen Vacancy ◽

First Principles ◽

Density Functional ◽

Density Functional Theory Calculations ◽

First Principles Calculations ◽

Generalized Gradient ◽

Functional Theory ◽

Light Region ◽

Application Potential ◽

Doped Zno

The electronic structures and optical characteristics of yttrium (Y)-doped ZnO monolayers (MLs) with vacancy (zinc vacancy, oxygen vacancy) were investigated by the first-principles density functional theory. Calculations were performed with the GGA+U (generalized gradient approximation plus U) approach, which can accurately estimate the energy of strong correlation semiconductors. The results show that the formation energy values of Y-doped ZnO MLs with zinc or oxygen vacancy (VZn, VO) are positive, implying that the systems are unstable. The bandgap of Y-VZn-ZnO was 3.23 eV, whereas that of Y-VO-ZnO was 2.24 eV, which are smaller than the bandgaps of pure ZnO ML and Y-doped ZnO MLs with or without VO. Impurity levels appeared in the forbidden band of ZnO MLs with Y and vacancy. Furthermore, Y-VZn-ZnO will result in a red-shift of the absorption edge. Compared with the pure ZnO ML, ZnO MLs with one defect (Y, VZn or VO), and Y-VZn-ZnO, the absorption coefficient of Y-VO-ZnO was significantly enhanced in the visible light region. These findings demonstrate that Y-VO-ZnO would have great application potential in photocatalysis.

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Structural, elastic and thermodynamic properties of A15-type compounds V3X (X = Ir, Pt and Au) from first-principles calculations

Modern Physics Letters B ◽

10.1142/s0217984916504145 ◽

2016 ◽

Vol 30 (35) ◽

pp. 1650414 ◽

Cited By ~ 6

Author(s):

Mingliang Wang ◽

Zhe Chen ◽

Dong Chen ◽

Cunjuan Xia ◽

Yi Wu

Keyword(s):

Thermodynamic Properties ◽

Debye Temperature ◽

First Principles ◽

Density Functional ◽

Coefficient Of Thermal Expansion ◽

Local Density ◽

Debye Model ◽

First Principles Calculations ◽

Generalized Gradient ◽

Experimental Values

The structural, elastic and thermodynamic properties of the A15 structure V3Ir, V3Pt and V3Au were studied using first-principles calculations based on the density functional theory (DFT) within generalized gradient approximation (GGA) and local density approximation (LDA) methods. The results have shown that both GGA and LDA methods can process the structural optimization in good agreement with the available experimental parameters in the compounds. Furthermore, the elastic properties and Debye temperatures estimated by LDA method are typically larger than the GGA methods. However, the GGA methods can make better prediction with the experimental values of Debye temperature in V3Ir, V3Pt and V3Au, signifying the precision of the calculating work. Based on the E–V data derived from the GGA method, the variations of the Debye temperature, coefficient of thermal expansion and heat capacity under pressure ranging from 0 GPa to 50 GPa and at temperature ranging from 0 K to 1500 K were obtained and analyzed for all compounds using the quasi-harmonic Debye model.

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First-Principles Studies of the Magnetic Properties of hcp Cr in Cr/Cu(111) and Cr/Ru(0001) Superlattices

MRS Proceedings ◽

10.1557/proc-721-e7.7 ◽

2002 ◽

Vol 721 ◽

Author(s):

G. Y. Guo

Keyword(s):

First Principles ◽

Density Functional ◽

Recent Observation ◽

Theoretical Calculations ◽

Ferromagnetic State ◽

Full Potential ◽

Generalized Gradient ◽

Plane Wave Method ◽

Wide Range ◽

Linearized Augmented Plane Wave

AbstractLatest first-principles density functional theoretical calculations using the generalized gradient approximation and highly accurate all-eleectron full-potential linearized augmented plane wave method, show that bulk hcp Cr would be a paramagnet and that no ferromagnetic state could be stabilized over a wide range of volume [1]. To understand the recent observation of the weakly ferromagnetic state of Cr in hcp Cr/Ru (0001) superlattices [2], the same theoretical calculations have been carried out for the hcp Cr3/Ru7 (0001) and hcp Cr3/fcc Cu6 (111) superlattices. The Cr/Ru superlattice is found to be ferromagnetic with a small magnetic moment of ∼0.31μB/Cr while in contrast, Cr/Cu superlattice is found to be nonmagnetic.

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Electronic structure of cubic BaTbO3 from first-principles pseudopotential calculations

Canadian Journal of Physics ◽

10.1139/p06-008 ◽

2006 ◽

Vol 84 (2) ◽

pp. 115-120 ◽

Cited By ~ 3

Author(s):

G Y Gao ◽

K L Yao ◽

Z L Liu

Keyword(s):

Electronic Structure ◽

First Principles ◽

Density Functional ◽

First Principles Calculations ◽

Generalized Gradient ◽

Functional Theory ◽

Exchange Correlation ◽

Pseudopotential Calculations ◽

Correlation Potential ◽

Density Contour

First-principles calculations of the electronic structure are performed for cubic BaTbO3 using the plane-wave pseudopotential method within the framework of density functional theory and using the generalized gradient approximation for the exchange-correlation potential. Our calculations show that cubic BaTbO3 is metallic, and that this metallic character is mainly governed by the Tb 4f electrons and the hybridization between the Tb 5d and O 2p states. From the analysis of the density of states, band structure, and charge density contour, we find that the chemical bonding between Tb and O is covalent while that between Ba and TbO3 is ionic. PACS Nos.: 71.15.Mb, 71.20.-b

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Structural and Electronic Properties of Orthorhombic Phase Bi2Se3 Based On First-Principles Study

Scientific Research Journal ◽

10.24191/srj.v16i2.6359 ◽

2019 ◽

Vol 16 (2) ◽

pp. 77 ◽

Cited By ~ 1

Author(s):

Muhammad Zamir Mohyedin ◽

Afiq Radzwan ◽

Mohammad Fariz Mohamad Taib ◽

Rosnah Zakaria ◽

Nor Kartini Jaafar ◽

...

Keyword(s):

Electronic Properties ◽

First Principles ◽

Density Functional ◽

Local Density ◽

Computer Code ◽

First Principles Calculation ◽

Generalized Gradient ◽

Exchange Correlation ◽

Percentage Difference ◽

Structural And Electronic Properties

Bi2Se3 is one of the promising materials in thermoelectric devices and very useful out of environmental concern due to its efficiency to perform at room temperature. Based on the first-principles calculation of density functional theory (DFT) by using CASTEP computer code, structural and electronic properties of Bi2Se3 were investigated. The calculation is conducted within the exchange-correlation of local density approximation (LDA) and generalized gradient approximation within the revision of Perdew-Burke-Ernzerhof (GGA-PBE) functional. It was found that the results are consistent with previous works of theoretical study with small percentage difference. LDA exchange-correlation functional method is more accurate and have a better agreement than GGA-PBE to describe the structural properties of Bi2Se3 which consist of lattice parameters. LDA functional also shown more accurate electronic structure of Bi2Se3 that consist of band structure and density of states (DOS) which consistent with most previous theoretical works with small percentage difference. This study proves the reliability of CASTEP computer code and show LDA exchange-correlation functional is more accurate in describing the nature of Bi2Se3 compared to the other functionals.

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First-principles study of calcium-based sulfur fixers and their products

Thermal Science ◽

10.2298/tsci210824350c ◽

2021 ◽

pp. 350-350

Author(s):

Guoyan Chen ◽

Jianing Chen ◽

Anchao Zhang ◽

Haoxin Deng ◽

Yanyang Mei ◽

...

Keyword(s):

Calcium Carbonate ◽

Power Plant ◽

Thermodynamic Properties ◽

Calcium Oxide ◽

First Principles ◽

Calcium Sulfate ◽

Density Functional ◽

Stable State ◽

Generalized Gradient ◽

Calcium Sulphoaluminate

Calcium-based sulfur-fixing agent, as the main sulfur-fixing product, is widely used in power plant boiler systems. In order to further study the thermodynamic properties and reaction characteristics of calcium-based sulfur fixing agent and its products, the method of combining power plant experiment with theory was used. The electronic structure, thermodynamic properties and density of states of quicklime, limestone, calcium sulfate and calcium sulphoaluminate have been calculated based on the first-principles ultra-soft pseudopotential plane wave method of density functional theory. The generalized gradient approximation algorithm isused to optimize the structure of various minerals to achieve the most stable state. The results show that the enthalpy, entropy, specific heat capacity at constant pressure and Gibbs free energy of calcium sulfonate vary greatly from 25K to 1000K, while the change of calcium oxide is small, and that of calcium carbonate and calcium sulfate are between them. It shows that calcium sulphoaluminate has strong stability and more energy is needed to destroy the molecular structure of calcium sulphoaluminate. Calcium oxide is the most unstable and requires less energy to react; Calcium carbonate and calcium sulfate are in between. The variation range of calcium sulfate is greater than that of calcium carbonate, indicating that the stability of calcium sulfate is higher than that of calcium carbonate. The experimental results show that the desulfurization efficiency of generating calcium sulphoaluminate is much higher than that of only generating calcium sulfate, indicating that calcium sulphoaluminate is very stable, which is consistent with the calculated results.

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First-Principles Study of Interaction of Lithium Atoms with (3, 3) Carbon Nanotubes

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.687-691.4311 ◽

2014 ◽

Vol 687-691 ◽

pp. 4311-4314 ◽

Cited By ~ 1

Author(s):

Shun Fu Xu ◽

Ling Min Li

Keyword(s):

Carbon Nanotubes ◽

First Principles ◽

Density Functional ◽

Vacancy Defect ◽

Single Wall Carbon Nanotubes ◽

Generalized Gradient ◽

Hydrogen Atoms ◽

Functional Theory ◽

Vacancy Defects ◽

Adsorption Mechanisms

In this paper, we have employed first-principles calculations to investigate the adsorption mechanisms of one lithium atom on the sidewalls of 1/2/3 H-adsorbed indefective/defective (3, 3) single-wall carbon nanotubes (CNTs) which have vacancy defects. Our calculations are performed within density functional theory (DFT) under the generalized gradient approximation (GGA) of Perdew, Burke, and Ernzerhof (PBE).Our results show that the lithium atoms strongly binds to the H-adsorbed (3, 3) nanotube. Lithium atoms can chemically adsorb on (3, 3) nanotube with the vacancy defect (MVD) without any energy barrier. The lithium adsorption will enhance the electrical conductivity of the nanotube. Further more, the structure of the (3, 3) nanotube with the MVD and hydrogen atoms will become more stable after the three kinds of lithium adsorption.

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DEFECT FORMATION AND MAGNETIC PROPERTIES OF COPPER DOPED ZnO NANOWIRES

Modern Physics Letters B ◽

10.1142/s0217984912500819 ◽

2012 ◽

Vol 26 (13) ◽

pp. 1250081 ◽

Cited By ~ 9

Author(s):

LI-BIN SHI

Keyword(s):

Magnetic Properties ◽

Density Functional ◽

Oxygen Vacancies ◽

Defect Formation ◽

Zno Nanowires ◽

Energy Calculation ◽

Generalized Gradient ◽

Total Energies ◽

Doped Zno ◽

P Type

Theoretical calculation based on density functional theory (DFT) and generalized gradient approximation (GGA) has been carried out in studying defect formation energies, ionization energies and magnetic properties of copper doped ZnO nanowires (NW). It is found from formation energy calculation that n-type Cu-doped ZnO NW is non-FM and p-type Cu-doped ZnO NW could be FM. The results show that total energies of FM coupling are lower than those of AFM coupling for majority of 12 configurations, indicating that the FM coupling between Cu atoms is more stable than AFM coupling. The FM stability is interpreted by Cu 3d energy level coupling. In addition, zinc and oxygen vacancies affecting FM coupling is also discussed. It is found that FM coupling can be tuned by zinc and oxygen vacancies.

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