First Principles Investigation of Geometrical and Electronic Structure of Semiconductor Fe1-XCoxSi2

2010 ◽  
Vol 663-665 ◽  
pp. 592-595
Author(s):  
Wan Jun Yan ◽  
Shi Yun Zhou ◽  
Fang Gui ◽  
Chun Hong Zhang ◽  
Xiao Tian Guo ◽  
...  
Keyword(s):  
Optical Properties ◽  
Electronic Structure ◽  
Plane Wave ◽  
First Principles ◽  
Function Theory ◽  
Density Function Theory ◽  
First Principle ◽  
Substitutional Doping ◽  
Pseudo Potential ◽  
Co Concentrations

The electronic structure and optical properties of Fe1-xCoxSi2 have been studied using the first principle plane-wave pseudo-potential based on the density function theory. Substitutional doping is considered with Co concentrations of x=0.0625, 0.125, 0.1875 and 0.25, respectively. The calculated results show that the volume of β-FeSi2 increase and the band gap decrease with increasing of Co.

First Principles Calculation of Geometrical and Electronic Structure of Semiconductor Fe1-xMnxSi2

2011 ◽  
Vol 213 ◽  
pp. 483-486
Author(s):  
Fang Gui ◽  
Shi Yun Zhou ◽  
Wan Jun Yan ◽  
Chun Hong Zhang ◽  
Xiao Tian Guo ◽  
...  
Keyword(s):  
Optical Properties ◽  
Electronic Structure ◽  
First Principles ◽  
Function Theory ◽  
Density Function Theory ◽  
First Principles Calculation ◽  
First Principle ◽  
Substitutional Doping ◽  
Pseudo Potential ◽  
Mn Concentrations

The electronic structure and optical properties of Fe1-xMnxSi2 have been studied using the first principle plane-wave pseudo-potential based on the density function theory. Substitutional doping is considered with Mn concentrations of x=0.0625, 0.125, 0.1875 and 0.25, respectively. The calculated results show that the volume of β-FeSi2 increase and the band gap increase with increasing of Mn.

Electronic structure and optical properties of anion-doped monoclinic NaTaO3 by first-principles calculations

2020 ◽  
Vol 98 (3) ◽  
pp. 233-238 ◽  
Author(s):  
Ji Zhang ◽  
Deming Zhang
Keyword(s):  
Optical Properties ◽  
Electronic Structure ◽  
First Principles ◽  
Function Theory ◽  
Density Function Theory ◽  
Band Gaps ◽  
Visible Range ◽  
First Principles Calculations ◽  
Substitutional Doping ◽  
Co Doped

First-principles density function theory calculations have been performed on the electronic structure and optical properties of mono-doped and co-doped monoclinic NaTaO3 systems. Doping of certain nonmetal ions (N, C, S, and P) and certain co-dopant pairs (C–N, S–N, P–N, and S–P) is investigated. Our calculations show that substitutional doping of C at a Na site, N at an O site, S at a Na site, and P at a Ta site require smaller formation energy based on the optimized structures of doped NaTaO3. In the case of mono-doped NaTaO3, the results indicate that the band gaps were all narrowed resulting in redshift of the absorption edge. However, for C–N, S–N, P–N, and S–P co-doped systems, though the band gap broadened, the appearance of mid-gap and movement of conduction band minimum (CBM) to Fermi energy led to absorption in the visible range. On the basis of the calculated results on nonmetal doped NaTaO3, we theoretically predicted that mono-doped NaTaO3 is more suitable for photocatalysts of water splitting.

Ab Initio Study of Structural and Optical Properties of SrTi0.5Nb0.5O3

2013 ◽  
Vol 846-847 ◽  
pp. 1935-1938
Author(s):  
Hong Liang Pan ◽  
Teng Li ◽  
Shi Liang Yang ◽  
Yi Ming Liu
Keyword(s):  
Optical Properties ◽  
Electronic Structure ◽  
Plane Wave ◽  
First Principles ◽  
Ab Initio Study ◽  
Structural And Optical Properties ◽  
Metallic Behavior ◽  
Conduction Bands ◽  
Structure Density ◽  
Pseudo Potential

The electronic structure, including band structure, density of states ( DOS) and optical properties of SrTi0.5Nb0.5O3are calculated from the first principles of plane wave ultra soft pseudo potential technology. The calculated results reveal that due to the electron doping, the Fermi level moves into the conduction bands and the system shows metallic behavior. The optical properties are also discussed in detail.

Ternary Cu3BiY3 (Y = S, Se, and Te) for Thin-Film Solar Cells

2013 ◽  
Vol 1538 ◽  
pp. 235-240 ◽  
Author(s):  
Mukesh Kumar ◽  
Clas Persson
Keyword(s):  
Thin Film ◽  
Optical Properties ◽  
First Principles ◽  
Function Theory ◽  
Density Function Theory ◽  
Band Gaps ◽  
Thin Film Solar Cells ◽  
Suitable Material ◽  
Conduction Bands ◽  
Alternative Material

ABSTRACTVery recently, Cu3BiS3 has been suggested as an alternative material for photovoltaic (PV) thin-film technologies. In this work, we analyze the electronic and optical properties of Cu3BiY3 with the anion elements Y = S, Se, and Te, employing a first-principles approach within the density function theory. We find that the three Cu3BiY3 compounds have indirect band gaps and the gap energies are in the region of 1.2–1.7 eV. The energy dispersions of the lowest conduction bands are small, and therefore the direct gap energies are only ∼0.1 eV larger than the fundamental gap energies. The flat conduction bands are explained by the presence of localized Bi p-states in the band gap region. Flat energy dispersion implies a large optical absorption, and the calculations reveal that the absorption coefficient of Cu3BiY3 is larger than 105 cm−1 for photon energies of ∼2.5 eV. The absorption is stronger than other Cu-S based materials like CuInS2 and Cu2ZnSnS4. Thereby, Cu3BiY3 has the potential to be a suitable material in thin-film PV technologies.

scholarly journals First-principles Calculation of the Electronic Structure and Optical Properties of ZnO Co-doped with Nb and Ta

2019 ◽  
Vol 25 (3) ◽  
pp. 238-245 ◽  
Author(s):  
Jinpeng WANG ◽  
Tao SHEN ◽  
Hongchen LIU
Keyword(s):  
Optical Properties ◽  
Electronic Structure ◽  
First Principles ◽  
First Principles Calculation ◽  
Ultraviolet Region ◽  
First Principle ◽  
Co Doping ◽  
First Principle Calculations ◽  
Function Loss ◽  
Co Doped

First-principle calculations have been performed to investigate the electronic structure and optical properties of ZnO co-doped with Nb and Ta. The three doping structures are set to: Zn0.9375Nb0.0625O, Zn0.9375Ta0.0625O and Zn0.875Nb0.0625Ta0.0625O. The experiments show that co-doping with Nb and Ta narrows the band gap. And it causes the Fermi level to shift upwards and enter the conduction band, while enhancing the conductivity of the doped system. In addition, it has been determined that the dielectric imaginary part of the dopant system is larger than that of the pure ZnO in the low energy region. The absorption side of the dopant system, on the other hand, exhibits a redshift. Furthermore, the transmittance of the ultraviolet region is significantly increased, and the function loss spectrum appears to redshift. This will provide a good theoretical basis for the study and the applications of photoelectric materials co-doped with Nb and Ta. DOI: http://dx.doi.org/10.5755/j01.ms.25.3.19956

Analyzing of Energy Band and Density of States of ZnO

2014 ◽  
Vol 492 ◽  
pp. 273-275
Author(s):  
Zhi Huan Lan ◽  
Man Yi Hou ◽  
Hong Yan Wang ◽  
Yi Guo Ji
Keyword(s):  
Electronic Structure ◽  
Plane Wave ◽  
Density Function ◽  
Density Of States ◽  
Energy Band ◽  
Function Theory ◽  
Energy Gap ◽  
Coulomb Repulsion ◽  
Density Function Theory ◽  
Full Potential

The electronic structure of ZnO is calculated by using an accurate full-potential linear plane-wave based on the density function theory and WIN2K package. The curves of energy band and density of states of ZnO are gained. The energy gap is 0.9eV that is better some of the computed results by theory approaches and smaller than the experimental value obtained by X spectra. After analyzing it is known that the coulomb repulsion between 3d state of Zn and 2p state of O is very strong leading to the increase in the energy of O2p and the energy gap become smaller.

THE EFFECT OF Ce–N CODOPING ON THE ELECTRONIC STRUCTURE AND OPTICAL PROPERTY OF ANATASE TiO2: A FIRST-PRINCIPLES STUDY

2014 ◽  
Vol 28 (06) ◽  
pp. 1450045 ◽  
Author(s):  
FEI MAO ◽  
QINGYU HOU ◽  
CHUNWANG ZHAO ◽  
SHAOQIANG GUO ◽  
YUE ZHANG
Keyword(s):  
First Principles ◽  
Function Theory ◽  
Density Function Theory ◽  
Anatase Tio2 ◽  
Shielding Effect ◽  
Thick Shell ◽  
Electron Hole ◽  
Shallow Level ◽  
Visible Effect ◽  
Pseudo Potential

Based on the first-principles plane wave ultra-soft pseudo potential (USP) method of density function theory pure N and Ce doped and Ce – N codoping anatase TiO 2 supercell models were established, respectively, and calculated their energy in this paper. The calculated results show that the three doping systems compared to the pure anatase TiO 2 band gap narrowed which results in red-shift of the optical absorption edges and Ce – N codoped anatase TiO 2 have the most obvious visible effect. Meanwhile, synergy is very effective for the separation of electron–hole pairs and the electrons have a better lifespan. Research found that the trend of the donor's movements at the shallow level of Ce – N codoped anatase TiO 2 is not obvious. This is due to its very thick shell, resulting in shielding effect of the outer layer of the Ce -4f.

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