Charged states and band-gap narrowing in codoped ZnO nanowires for enhanced photoelectrochemical responses: Density functional first-principles calculations

Zhuo Xu; Qing-Rong Zheng; Gang Su

doi:10.1103/physrevb.85.075402

First-Principles Calculations on Pure and Ga-Doped Anatase TiO2

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.156-157.1385 ◽

2010 ◽

Vol 156-157 ◽

pp. 1385-1388

Author(s):

Rui Qing Xu ◽

Lan Fang Yao ◽

Lin Li ◽

Shuo Wang ◽

Lin Lin Tian ◽

...

Keyword(s):

Band Gap ◽

First Principles ◽

Density Functional ◽

Correlation Energy ◽

Anatase Tio2 ◽

First Principles Calculations ◽

Generalized Gradient ◽

Functional Theory ◽

The Density Functional Theory ◽

Band Gap Narrowing

First-principles calculations using the plane-wave pseudo-potential (PWPP) method based on the density functional theory (DFT) is employed to study the crystal structure, band gap, density of states of anatase TiO2 doped with gadolinium (Gd). The generalized gradient approximation (GGA) based on exchange-correlation energy optimization is employed to calculate them. The calculated results demonstrate that the mixing of gadolinium dopants induces states with original titanium 3d and oxygen 2p valence band attributes to the band gap narrowing. This can enhance the photocatalytic activity of anatase TiO2.

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First-Principles Calculations on Pure and Y-Doped Anatase TiO2

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.562-565.1166 ◽

2013 ◽

Vol 562-565 ◽

pp. 1166-1170 ◽

Cited By ~ 1

Author(s):

Xiong Tang ◽

Lan Fang Yao ◽

Xin Pei Yan ◽

Jun Long Kang

Keyword(s):

Band Gap ◽

First Principles ◽

Density Functional ◽

Correlation Energy ◽

Partial Density ◽

First Principles Calculations ◽

Generalized Gradient ◽

Functional Theory ◽

Calculation Results ◽

Band Gap Narrowing

Using the First principles calculations, the crystal structure, band gap, total and partial density of states (DOS) of anatase TiO2and anatase TiO2doped with Yttrium were calculated by a plane-wave pseudopotential (PWPP) method based on density functional theory (DFT). The generalized gradient approximation (GGA) based on exchange-correlation energy optimization was employed to calculate them. From the calculation results, the band gap of anatase TiO2and Y3+doped TiO2are about 2.15eV and 0.86eV. The calculated results demonstrated that the mixing of Yttrium (Y) dopants induces states with original titanium 3d and oxygen 2p valence band attributes to the band gap narrowing. This can enhance the photocatalytic activity of anatase TiO2.

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Synergistic Effects on Band Gap-Narrowing in Titania by Codoping from First-Principles Calculations

Chemistry of Materials ◽

10.1021/cm903688z ◽

2010 ◽

Vol 22 (5) ◽

pp. 1616-1623 ◽

Cited By ~ 110

Author(s):

Run Long ◽

Niall J. English

Keyword(s):

Band Gap ◽

First Principles ◽

Synergistic Effects ◽

First Principles Calculations ◽

Band Gap Narrowing

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First-Principle Study of Effect of Strain on the Band Structure of Germanane Monolayer

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.787.25 ◽

2018 ◽

Vol 787 ◽

pp. 25-30

Author(s):

Lei Liu ◽

Yan Ju Ji ◽

Yi Fan Liu

Keyword(s):

Band Structure ◽

Band Gap ◽

First Principles ◽

Density Functional ◽

Catalytic Properties ◽

Significant Implication ◽

First Principle ◽

First Principles Calculations ◽

Biaxial Strain ◽

Functional Theory

The effect of strain on the band structure of the GeH monolayer has been investigated by first-principles calculations based on density functional theory. The results show that the change of the band gap under the zigzag strain, the armchair strain and the biaxial strain is nonlinear. The effect of the biaxial strain on the band gap is the most obvious. In addition, the changes of energy under the three kinds of strain are asymmetric and the biaxial strain make the energy change the most. This work has significant implication of strain to tune optical catalytic properties of GeH monolayer.

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First-Principles Calculations on the Electronic Structure of ZnO Nanowires

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.198-199.23 ◽

2012 ◽

Vol 198-199 ◽

pp. 23-27

Author(s):

Nan Zhang ◽

Hong Sheng Zhao ◽

Dong Yang ◽

Wen Jie Yan

Keyword(s):

Electronic Structure ◽

Band Gap ◽

Valence Band ◽

Conduction Band ◽

First Principles ◽

Density Functional ◽

Valence Band Maximum ◽

Zno Nanowires ◽

Cross Sectional ◽

Quantum Size

Based upon the density functional theory (DFT) in this paper, the first-principles approach is used to study the electronic structure of different cross-sectional diameters of ZnO [0001] nanowires of wurtzite structure. The results show that ZnO [0001] nanowires have a wide direct band gap. Located in the G-point of the Brillouin zone the conduction band minimum and valence band maximum are relatively smooth. The conduction band is mainly composed of Zn 4s and Zn 4p states, and the valence band is composed of Zn 3d and O 2p states. The effective mass of conduction band electrons and valence band holes are large while their mobility is very low which show that conductive ability of pure defect-free [0001] ZnO nanowires is weak. Along with the increase of the cross-sectional diameters, the band gap gradually decreases that indicates quantum size effects are obvious in the nano size range.

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Electronic structure and magnetic ordering in gadolinium-doped AlGaN from LSDA + U calculations

International Journal of Computational Materials Science and Engineering ◽

10.1142/s2047684118500197 ◽

2018 ◽

Vol 07 (03) ◽

pp. 1850019 ◽

Cited By ~ 2

Author(s):

S. Belhachi ◽

S. Amari ◽

B. Bouhafs

Keyword(s):

Density Functional Theory ◽

Magnetic Properties ◽

Band Gap ◽

First Principles ◽

Density Functional ◽

Magnetic Ordering ◽

First Principles Calculations ◽

Functional Theory ◽

The Density Functional Theory ◽

Indirect Band Gap

We present first-principles calculations of the structural, electronic and magnetic properties of Gd-doped [Formula: see text] based on the density functional theory within [Formula: see text] schemes. It is found that Gd atom favors substituting for Al site. Compared with undoped [Formula: see text], the Gd-doped [Formula: see text] has become an indirect band gap semiconductor of reduced band gap. The magnetic moment [Formula: see text] per molecule mainly comes from Gd ion with little contribution from the Ga, Al and N atoms. It is confirmed that the ferromagnetic configuration is stable for [Formula: see text]. It is found also that there is hybridization between the forbital of the Gd atom and the [Formula: see text] orbital of the N atom.

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FIRST-PRINCIPLES CALCULATIONS ON ELECTRONIC STRUCTURES OF TiO2 ANATASE (101) SURFACES WITH N IMPURITIES

Modern Physics Letters B ◽

10.1142/s0217984911025535 ◽

2011 ◽

Vol 25 (02) ◽

pp. 119-129 ◽

Cited By ~ 4

Author(s):

QI LI CHEN ◽

GUANG ZHENG ◽

KAI HUA HE ◽

BO LI

Keyword(s):

Band Gap ◽

Electronic Structures ◽

Density Functional ◽

First Principles Calculations ◽

Functional Theory ◽

Tio2 Anatase ◽

Exchange Correlation ◽

N Doping ◽

Band Gap Narrowing ◽

Coefficient Method

The electronic structures of nitrogen ( N )-doped TiO 2 anatase (101) surfaces have been investigated by density functional theory (DFT) plane-wave pseudopotential method with general gradient approximation (GGA) + U (Hubbard coefficient) method being adopted to describe the exchange-correlation effects. Both substitutional and interstitial N doping have been considered in this paper as well as the case of surface N adsorption. The results demonstrated that there is no obvious band gap narrowing observed by introducing N impurities except several N 2p states lying in the gap, whereas the introduction of oxygen vacancy was confirmed playing an important role on band gap narrowing. The results accord well with some experimental results.

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STRUCTURAL, ELECTRONIC, THERMODYNAMIC AND THERMAL PROPERTIES OF ZINC-BLENDE InP, InAs AND THEIR InAsx P1-x TERNARY ALLOYS VIA FIRST PRINCIPLES CALCULATIONS

International Journal of Modern Physics B ◽

10.1142/s021797921350166x ◽

2013 ◽

Vol 27 (27) ◽

pp. 1350166 ◽

Cited By ~ 12

Author(s):

O. NEMIRI ◽

S. GHEMID ◽

Z. CHOUAHDA ◽

H. MERADJI ◽

F. EL HAJ HASSAN

Keyword(s):

Thermal Properties ◽

Bulk Modulus ◽

Band Gap ◽

Lattice Constant ◽

First Principles ◽

Density Functional ◽

Experimental Studies ◽

Ternary Alloys ◽

Full Potential ◽

First Principles Calculations

First-principles calculations are performed to study the structural, electronic, thermodynamic and thermal properties of the InP and InAs bulk materials and InAs x P 1-x ternary alloys using the full potential-linearized augmented plane wave method (FP-LAPW) within the density functional theory (DFT). The dependence of the lattice constant, bulk modulus, band gap, Debye temperature, heat capacity and mixing entropy on the composition x was analyzed. The lattice constant for InAs x P 1-x alloys exhibits a marginal deviation from the Vegard's law. A large deviation of the bulk modulus from linear concentration dependence (LCD) was observed for our alloys. We found that the composition dependence of the energy band gap is almost linear by using the mBJ and EV-GGA approximations. The microscopic origins of the gap bowing were explained and detailed by using the approach of Zunger and co-workers. Furthermore, the calculated phase diagram shows a miscibility gap for these alloys with a high critical temperature. Thermal effects on some macroscopic properties of InAs x P 1-x alloys are predicted using the quasi-harmonic Debye model, in which the phononic effects are considered. This is the first quantitative theoretical prediction of the thermal properties of the InAs x P 1-x alloys, and we still expect the confirmation of experimental studies.

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A first-principle study on the electronic properties of substitutionally Cu (I, II)-doped LiNbO3

Journal of Advanced Dielectrics ◽

10.1142/s2010135x18200023 ◽

2018 ◽

Vol 08 (01) ◽

pp. 1820002 ◽

Cited By ~ 2

Author(s):

Xiaobin Liu ◽

Wenxiu Que ◽

Yucheng He ◽

Huanfu Zhou

Keyword(s):

Band Structure ◽

Band Gap ◽

Electronic Properties ◽

First Principles ◽

Density Functional ◽

First Principles Calculations ◽

Density Of State ◽

Functional Theory ◽

The Density Functional Theory ◽

Small Band

The electronic properties of Cu-doped lithium niobate (LiNbO3) systems are investigated by first-principles calculations. In this work, we focus on substitutionally Cu[Formula: see text]Li-doped LiNbO3 system with cuprous and cupric doping, which corresponds to the Li[Formula: see text]Cu[Formula: see text]NbO3 and Li[Formula: see text]Cu[Formula: see text]NbO3 [abbreviated as (Li, Cu I)NbO3 and (Li, Cu II)NbO3]. The density functional theory (DFT) calculations show that the electronic property of LiNbO3 is completely different from (Li, Cu I)NbO3 and (Li, Cu II)NbO3. The calculated band structure and density of state (DOS) of (Li, Cu I)NbO3 show a small band gap of 1.34[Formula: see text]eV and the top of valance band (VB) is completely composed of a doping energy level originating from Cu 3d filled orbital. However, the calculated band structure and DOS of (Li, Cu II)NbO3 show a relatively large band gap of 2.22[Formula: see text]eV and the top of VB is mainly composed of Cu 3d unfilled orbital and O 2p orbital.

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Band gap engineering of ZnO substituted with nitrogen and fluorine, ZnO1−3xN2xFx: a hybrid density functional study

RSC Advances ◽

10.1039/c6ra17693c ◽

2016 ◽

Vol 6 (101) ◽

pp. 99088-99095 ◽

Cited By ~ 2

Author(s):

S. Kumar ◽

Durgesh Kumar Sharma ◽

S. Auluck

Keyword(s):

Density Functional Theory ◽

Band Gap ◽

First Principles ◽

Density Functional ◽

Functional Study ◽

First Principles Calculations ◽

Functional Theory ◽

Band Gap Engineering ◽

Hybrid Density Functional ◽

Co Doped

A series of first principles calculations within density functional theory (DFT) have been performed for ZnO, co-doped with N and F with the aim of engineering the band gap and improving its application to photo-absorption activity.

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