scholarly journals Structural and Optical Properties of α-Quartz Cluster with Oxygen-Deficiency Centers

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Yin Li ◽  
Xi Chen ◽  
Chuanghua Yang ◽  
Liyuan Wu ◽  
Ru Zhang
Keyword(s):  
Optical Properties ◽  
Density Functional ◽  
Oxygen Deficiency ◽  
Cluster Models ◽  
Structural And Optical Properties ◽  
Theoretical Support ◽  
The Density Functional Theory ◽  
Metastable Structure ◽  
Time In Literature ◽  
Equilibrium Length

The structural and optical properties of α-quartz cluster with oxygen-deficiency centers (ODCs) defects have been investigated based on the density functional theory (DFT). For cluster models with ODC(I) defect, with the increasing of cluster size and shape, the equilibrium length of Si-Si bond decreases. The excitation peaks of cluster models with ODC(I) defect are from 6.87 eV to 7.39 eV, while the excitation peaks of cluster models with ODC(II) defect are from 5.20 eV to 5.47 eV. We also study the interconversion between ODCs (≡Si-Si≡ bond and divalent Si) induced by UV irradiation. Our study predicted the existence of a metastable structure of ODC(I) for the first time in literature. Our results are in good agreement with the previous results and provide strong theoretical support to the viability of the processes.

The Study on the Structural and Optical Properties of C-F Codoped Zinc Oxide from Ab Initio Calculations

2011 ◽  
Vol 311-313 ◽  
pp. 1267-1270
Author(s):  
Chun Ying Zuo ◽  
Jing Wen ◽  
Cheng Zhong ◽  
Zhong Cheng Wu ◽  
Zhong Cheng Wu
Keyword(s):  
Optical Properties ◽  
Density Functional ◽  
Lattice Mismatch ◽  
Generalized Gradient ◽  
Structural And Optical Properties ◽  
Functional Theory ◽  
Absorption Edge Shift ◽  
Pseudopotential Calculations ◽  
The Density Functional Theory ◽  
Lower Energy Region

The structural and optical properties of C-doped and C-F colonel Zoo compounds are investigated by using a first principle method with the plane wave pseudopotential calculations, based on the density functional theory(DFT), within generalized-gradient approximation (GGA). We discuss the structural properties by comparison with C-Al and C-Ga doped systems and the calculated results demonstrate that the c/a is smaller than C doped ZnO when incorporating F into the system and C-F codoping causes a smaller lattice mismatch compared with the C-Al codoped ZnO. Moreover, we focus on the complex dielectric function in order to investigate the optical properties. By analysing the results, we remark that the absorption edge shift the lower energy region(red shift) when incorporating C-F into ZnO compound.

scholarly journals Electronic Structural and Optical Properties of Multilayer Blue Phosphorus: A First-Principle Study

2019 ◽  
Vol 2019 ◽  
pp. 1-8
Author(s):  
Bing Li ◽  
Ceng-Ceng Ren ◽  
Shu-Feng Zhang ◽  
Wei-Xiao Ji ◽  
Chang-Wen Zhang ◽  
...  
Keyword(s):  
Optical Properties ◽  
Density Functional ◽  
Ultraviolet Region ◽  
Structural And Optical Properties ◽  
Functional Theory ◽  
Optical Absorption Peak ◽  
The Density Functional Theory ◽  
Direct Band ◽  
The Stability ◽  
Unexpected Transformation

Using the density functional theory, we systematically calculated the stability, electronic, and optical properties of monolayer and multilayer blue phosphorus. The results show the structures are all dynamically stable, and the gaps decrease with an increase of the number of layers. An unexpected transformation from indirect to direct band gaps is also observed as the tensile strain increases. In addition, the optical properties indicate the optical absorption peak of the material is in the ultraviolet region.

Theoretical Study of Electronic, Structural, and Optical properties of Armchair, Zigzag and Chiral Silicon-Germanium Nanotubes

2021 ◽  
Author(s):  
Alejandro de Jesus Herrera Carbajal ◽  
Ventura Rodríguez-Lugo ◽  
Juan Hernández Ávila ◽  
Ariadna Sanchez-Castillo
Keyword(s):  
Density Functional Theory ◽  
Optical Properties ◽  
Theoretical Analysis ◽  
Silicon Germanium ◽  
Density Functional ◽  
Theoretical Study ◽  
Structural And Optical Properties ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Germanium Alloy

In this work we have studied infinite silicon-germanium alloy nanotubes of several types: armchair, zigzag and chiral, using a theoretical analysis based on the density functional theory as implemented in...

Investigations of the Optical Properties of LaNi5 and LaNi4.5Sn0.5

2013 ◽  
Vol 321-324 ◽  
pp. 495-498 ◽  
Author(s):  
Dong Chen ◽  
Chao Xu
Keyword(s):  
Experimental Data ◽  
Refractive Index ◽  
Optical Properties ◽  
Density Functional ◽  
Low Frequency ◽  
Potential Method ◽  
Frequency Region ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Pseudo Potential

The reflectivity, loss function, refractive index, extinction coefficient and dielectric function of the LaNi5and LaNi4.5Sn0.5intermetallic compounds are investigated through the plane-wave pseudo-potential method based on the density functional theory. The effects of Sn impurity are discussed and some interesting features are found in the low frequency region. Some important optical properties such as static dielectric constant and static refractive index are obtained. The equation [n (0)]2=ε1(0)is satisfied according to our calculation, which indicates that our results are correct and reasonable. Nevertheless, the calculated results need to be testified in the future due to the lack of experimental data.

scholarly journals Oxygen vacancy and doping atom effect on electronic structure and optical properties of Cd2SnO4

RSC Advances ◽  
2018 ◽  
Vol 8 (2) ◽  
pp. 640-646 ◽  
Author(s):  
Mei Tang ◽  
JiaXiang Shang ◽  
Yue Zhang
Keyword(s):  
Optical Properties ◽  
Electronic Structure ◽  
Oxygen Vacancy ◽  
Density Functional ◽  
Generalized Gradient ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
La Doped ◽  
Doping Atom ◽  
Atom Effect

The electronic structure and optical properties of oxygen vacancy and La-doped Cd2SnO4 were calculated using the plane-wave-based pseudopotential method based on the density functional theory (DFT) within the generalized gradient approximation (GGA).

Electronic and optical properties of zinc-blende GeC by first principles study

2015 ◽  
Vol 29 (20) ◽  
pp. 1550103
Author(s):  
Jinhui Zhai ◽  
Jinguang Zhai ◽  
Ajun Wan
Keyword(s):  
Optical Properties ◽  
First Principles ◽  
Density Functional ◽  
Dielectric Constants ◽  
Electronic And Optical Properties ◽  
Optical Functions ◽  
Zinc Blende ◽  
The Density Functional Theory ◽  
Valence Bands ◽  
Energy Dependent

The electronic and optical properties of zinc-blende (zb)[Formula: see text]GeC have been investigated using first principles calculations based on the density functional theory (DFT). The obtained band gap of zb–GeC is 2.30[Formula: see text]eV by means of Heyd–Scuseria–Ernzerhof (HSE) functional. We have discussed the energy-dependent optical functions including dielectric constants, refractive index, absorption, reflectivity, and energy-loss spectrum in detail. The results reveal that zb–GeC has a higher static dielectric constant compared with that of zb–SiC. The optical functions are mainly associated with the interband transitions from the occupied valence bands (VBs) Ge[Formula: see text][Formula: see text] and C[Formula: see text][Formula: see text] states to Ge[Formula: see text][Formula: see text], [Formula: see text] and C[Formula: see text][Formula: see text] states of the unoccupied conduction bands (CBs).

First Principles Calculations of Electronic Structure and Optical Properties of Cu-Doped SnS2

2013 ◽  
Vol 373-375 ◽  
pp. 1965-1969
Author(s):  
Kun Nan Qin ◽  
Ling Zhi Zhao ◽  
Yong Mei Liu ◽  
Fang Fang Li ◽  
Chao Yang Cui
Keyword(s):  
Optical Properties ◽  
Electronic Structure ◽  
First Principles ◽  
Density Functional ◽  
Optical Absorption Coefficient ◽  
Impurity Level ◽  
First Principles Calculations ◽  
Absorption Region ◽  
Functional Theory ◽  
The Density Functional Theory

The electronic structure and optical properties of Cu-doped SnS2with Sn-substituted content of 0, 12.5 and 37.5 at.% were successfully calculated by the first principles plane-wave pseudopotentials based on the density functional theory. It is found that the intermediate belts appear near the Fermi level and the energy band gap becomes narrower after the doping of the Cu atoms. The absorption peaks show a remarkable redshift and the absorption region broadens relatively after introducing acceptor impurity level. When Sn atoms of 37.5 at% were substituted by Cu, the optical absorption coefficient is significantly improved in the frequency range below 5.58 eV and over 8.13 eV.

Structural and optical properties of Ba3(Nb6−xTax)Si4O26 (x = 0.6, 1.8, 3.0, 4.2, 5.4)

2019 ◽  
Vol 34 (4) ◽  
pp. 331-338
Author(s):  
W. Wong-Ng ◽  
G. Y. Liu ◽  
W. F. Liu ◽  
Y. Q. Yang ◽  
S. Y. Wang ◽  
...  
Keyword(s):  
Solid Solution ◽  
Optical Properties ◽  
Density Functional ◽  
Salient Feature ◽  
Lattice Parameter ◽  
Structural And Optical Properties ◽  
Functional Theory ◽  
Coordination Environment ◽  
Distorted Octahedra ◽  
Bond Valence Sum

Structure and optical properties have been successfully determined for a series of niobium- and tantalum-containing layered alkaline-earth silicate compounds, Ba3(Nb6−xTax)Si4O26 (x = 0.6, 1.8, 3.0, 4.2, 5.4). The structure of this solid solution was found to be hexagonal P-62m (No. 189), with Z = 1. With x increases from 0.6 to 5.4, the lattice parameter a increases from 8.98804(8) to 9.00565(9) Å and c decreases from 7.83721(10) to 7.75212(12) Å. As a result, the volume decreases from 548.304(11) to 544.479(14) Å3. The (Nb/Ta)O6 distorted octahedra form continuous chains along the c-axis. These (Nb/Ta)O6 chains are in turn linked with the Si2O7 groups to form distorted pentagonal channels in which Ba ions were found. These Ba2+ ions have full occupancy and a 13-fold coordination environment with neighboring oxygen sites. Another salient feature of the structure is the linear Si–O–Si chains. When x in Ba3(Nb6−xTax)Si4O26 increases, the bond valence sum (BVS) values of the Ba sites increase slightly (2.09–2.20), indicating the size of the cage becoming progressively smaller (over-bonding). While SiO cages are also slightly smaller than ideal (BVS range from 4.16 to 4.19), the (Nb/Ta)O6 octahedral cages are slightly larger than ideal (BVS range from 4.87 to 4.90), giving rise to an under-bonding situation. The bandgaps of the solid solution members were measured between 3.39 and 3.59 eV, and the x = 3.0 member was modeled by density functional theory techniques to be 3.07 eV. The bandgaps of these materials indicate that they are potential candidates for ultraviolet photocatalyst.

scholarly journals DFT Calculation on the Electronic Structure and Optical Properties of InxGa1-xN Alloy Semiconductors

2019 ◽  
Vol 26 (2) ◽  
pp. 127-132
Author(s):  
Xuewen WANG ◽  
Wenwen LIU ◽  
Chunxue ZHAI ◽  
Jiangni YUN ◽  
Zhiyong ZHANG
Keyword(s):  
Optical Properties ◽  
Absorption Spectrum ◽  
Electronic Structure ◽  
Density Functional ◽  
Dft Calculation ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Photoelectric Performance ◽  
The Density Functional Theory ◽  
Alloy Semiconductors

Using the density functional theory (DFT) of the first principle and Generalized gradient approximation method, the electronic structures and optical properties of the InxGa1-xN crystals with different x (x = 0.25, 0.5, 0.75, 1) have been calculated in this paper. The influence of the electronic structure on the properties has been analyzed. Then the influence of doping quantity on the characteristics has been summarized, which also indicates the trend of complex dielectric function, absorption spectrum and transitivity. With the increase of x, the computational result shows that the optical band gap (i.e.Eg) of the InxGa1-xN crystal tends to be narrow, then the absorption spectrum shifts to the low-energy direction. And the Fermi energy slightly moves to the bottom of conduction band which would cause the growth of conductivity by increasing x. In a word, the InxGa1-xN compound can be achieved theoretically the adjustable Eg and photoelectric performance with x, which will be used in making various optoelectronic devices including solar cell and sensors.

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