Electronic Structure and Optical Properties of ZnO with Antisite Defects

2013 ◽  
Vol 341-342 ◽  
pp. 301-306
Author(s):  
X.J. Xie ◽  
W.H. Wang ◽  
L.Y. Li ◽  
X.G. Luo ◽  
Y.H. Cheng
Keyword(s):  
Optical Properties ◽  
Electronic Structure ◽  
Optical Absorption ◽  
Electronic Structures ◽  
Low Energy ◽  
Visible Light Region ◽  
Optical Absorption Edge ◽  
Light Region ◽  
Level Shifts ◽  
Antisite Defects

We investigate the electronic structures and optical properties of ZnO with antisite defects OZn using the density function pseudopotential method. Our results show that the Fermi level shifts into the conduction band after introducing one or two OZn defects into ZnO supercell, indicating that the system displays a metallic-like characteristic. Moreover, the antisite defects lead to a redshift of the optical absorption edge and obvious optical absorption in the visible light region. Especially, the optical properties are influenced by the configurations of two OZn defects in our considered ZnO supercell. The strongest optical absorption occurs when the two defects are connected by-Zn-O-Zn-bond in the ab plane. These findings are possibly applicable for designing new optoelectronic and photoelectrochemical devices with improved low energy light absorption.

OPTICAL ABSORPTION AND LUMINESCENCE OF C60F2X COMPOUNDS

2002 ◽  
Vol 09 (02) ◽  
pp. 1339-1343 ◽  
Author(s):  
P. V. DUDIN ◽  
S. V. AMARANTOV ◽  
V. G. STANKEVITCH ◽  
V. N. BEZMELNITSYN ◽  
A. V. RYZKOV ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Optical Absorption ◽  
Electronic Structures ◽  
Electronic Excitation ◽  
Visible Region ◽  
Low Energy ◽  
Luminescence Spectra ◽  
Electron Subsystem ◽  
Component Structure ◽  
Two Component

We have investigated the reduction of initial C 60 electronic structure under the influence of a growing number of attached fluorines in C 60 F 48, C 60 F 36, C 60 F 24, and C 60 F 18. The reduction of the low-energy π-electron subsystem reveals itself in lowering of the optical absorption in the visible region and in gradual blueshift of the luminescence. The absorption of C 60 F 24 and C 60 F 18 films strongly resembles that of C 60, thus showing the similarity of electronic structures of C 60 and these compounds. This resemblance disappears in the absorption spectra of C 60 F 48 and C 60 F 36. The absorption of these compounds looks like that of C 6 H 6, because the π-bonds are isolated. The luminescence of C 60 F 18 film has an unexpected two-component structure, with the first component close to the C 60 luminescence spectra, and the second one lying pproximately in the same region with C 60 F 36. We attribute this splitting of luminescence spectra to the two different channels for relaxation of the electronic excitation. The first one is correlated with the fluorinated part of the C 60 F 18 molecule, the second one with the part free of fluorine atoms.

Improved visible-light absorbance of monolayer MoS2 on AlN substrate and its angle-dependent electronic structures

2018 ◽  
Vol 20 (46) ◽  
pp. 29131-29141 ◽  
Author(s):  
Feifei Li ◽  
Changmin Shi ◽  
Dongchao Wang ◽  
Guangliang Cui ◽  
Pinhua Zhang ◽  
...  
Keyword(s):  
Optical Absorption ◽  
Visible Light ◽  
Electronic Structures ◽  
Band Gaps ◽  
Type Ii ◽  
Visible Light Region ◽  
Monolayer Mos2 ◽  
Band Structures ◽  
Light Region ◽  
Light Absorbance

The band gaps of type-II band structures in Mo–N stacking configuration are sensitive to the strains for MoS2/AlN hetero-structures, which exhibit more considerable optical absorption in the visible-light region than MoS2 and AlN monolayers.

THE ELECTRONIC AND OPTICAL PROPERTIES OF X-DOPED SrTiO3 (X = Rh, Pd, Ag): A FIRST-PRINCIPLES CALCULATIONS

2014 ◽  
Vol 28 (09) ◽  
pp. 1450031 ◽  
Author(s):  
BO QIU ◽  
XIN-GUO YAN ◽  
WEI-QING HUANG ◽  
GUI-FANG HUANG ◽  
CHAO JIAO ◽  
...  
Keyword(s):  
Optical Properties ◽  
Visible Light ◽  
First Principles ◽  
Visible Light Region ◽  
First Principles Calculations ◽  
Optical Absorption Edge ◽  
Electronic And Optical Properties ◽  
Light Region ◽  
Recombination Centers ◽  
Theoretical Results

The electronic and optical properties of X-doped (X = Rh, Pd, Ag) cubic SrTiO 3 in perovskite structure are investigated using first-principles calculations. The strength of the Ti–O bonds near the substitutional X impurity is found to be weakened by the shorter X–O bonds. Three types of electronic characteristics due to X-doping are demonstrated. X-doping decreases the band gap of SrTiO 3, extending the optical absorption edge to visible light. Although Pd-doped SrTiO 3 has the greatest absorption in the visible light region, its photocatalytic activity is lower than that of Rh-doped SrTiO 3, because the intermediate bands from the 4d orbitals of the Pd dopant act as recombination centers. The theoretical results coincide with the available experimental results.

scholarly journals Comparative Study on Electronic Structure and Optical Properties of α-Fe2O3, Ag/α-Fe2O3 and S/α-Fe2O3

Metals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 424
Author(s):  
Cuihua Zhao ◽  
Baishi Li ◽  
Xi Zhou ◽  
Jianhua Chen ◽  
Hongqun Tang
Keyword(s):  
Optical Properties ◽  
Optical Absorption ◽  
Electronic Structures ◽  
Density Functional ◽  
Peak Strength ◽  
Visible Range ◽  
High Symmetry ◽  
Functional Theory ◽  
Optical Absorption Peak ◽  
Calculation Results

The electronic structures and optical properties of pure, Ag-doped and S-doped α-Fe2O3 were studied using density functional theory (DFT). The calculation results show that the structure of α-Fe2O3 crystal changes after Ag and S doping, which leads to the different points of the high symmetry of Ag-doped and S-doped α-Fe2O3 with that of pure α-Fe2O3 in the energy band, as well as different Brillouin paths. In addition, the band gap of α-Fe2O3 becomes smaller after Ag and S doping, and the optical absorption peak shifts slightly toward the short wavelength, with the increased peak strength of S/α-Fe2O3 and the decreased peak strength of Ag/α-Fe2O3. However, the optical absorption in the visible range is enhanced after Ag and S doping compared with that of pure α-Fe2O3 when the wavelength is greater than 380 nm, and the optical absorption of S-doped α-Fe2O3 is stronger than that of Ag-doped α-Fe2O3.

THE OPTICAL AND EPR SPECTRA OF THE HYDROGEN ANNEALED KTiOPO4 CRYSTALS

1999 ◽  
Vol 13 (18) ◽  
pp. 645-648 ◽  
Author(s):  
V. A. NAZAROVA ◽  
V. N. EFIMOV ◽  
M. A. LARUHIN
Keyword(s):  
Optical Absorption ◽  
Visible Light ◽  
Epr Spectra ◽  
Hydrogen Treatment ◽  
Visible Light Region ◽  
Light Region

In this work, the results of the hydrogen treatment and following that, the annealing in air of flux-grown KTiOPO 4 (KTP) crystals are represented. We have tried to correlate our optical and EPR results. The main conclusion is that the Ti 3+ A, B, C, D centers are not associated with optical absorption in the visible light region.

Optical Properties and Electronic Structures of Sexithiophene

2010 ◽  
Vol 428-429 ◽  
pp. 475-478 ◽  
Author(s):  
Bao Gai Zhai ◽  
Yuan Ming Huang
Keyword(s):  
Optical Properties ◽  
Optical Absorption ◽  
Ultraviolet Light ◽  
Organic Semiconductor ◽  
Electronic Structures ◽  
Light Emission ◽  
Visible Spectroscopy ◽  
Time Resolved ◽  
Pump And Probe ◽  
Green Photoluminescence

The optical properties and electronic structures of an organic semiconductor sexithiophene have been investigated with ultraviolet-visible spectroscopy, cw photospectroscopy and time-resolved photospectroscopy, respectively. Sexithiophene in dilute tetrahydrofuran solutions can absorb photons at 400 nm while it can give off strong green photoluminescence at 550 nm under the excitation of 325 nm ultraviolet light. With the assistance of calculated electronic structures and pump-and-probe characterization, our results indicate that both the optical absorption and the light emission of the sexithiophene are controlled by the p-conjugation of the oligothiophene.

Tuning band gap and optical properties of SnX2 nanosheets: Hybrid functional studies

2016 ◽  
Vol 30 (10) ◽  
pp. 1650120 ◽  
Author(s):  
P. Guo ◽  
Y. W. Luo ◽  
Y. Jia
Keyword(s):  
Optical Properties ◽  
Optical Absorption ◽  
Band Gap ◽  
Electronic Structures ◽  
Threshold Values ◽  
Hybrid Functional ◽  
Functional Studies ◽  
Quantum Size ◽  
Light Activity ◽  
Optical Applications

Based on hybrid functional calculations, the electronic structures and optical properties are investigated in the monolayer and bilayer tin dichalcogenides SnX2 (X = S and Se) nanosheets. Numerical results show that quantum size effects are obvious on the electronic structures and optical absorption in the SnS2 and SnSe2 nanosheets. The band gap values increase when the nanosheets layer numbers decrease. Moreover, for SnSe2 nanosheet, the optical absorption coefficients are high and its threshold values lie in the visible light activity range. These results are interesting and indicate that SnS2 and SnSe2 nanosheets may serve as the promising candidates for visible optical applications.

Electronic Structure and Optical Properties of Cu-Doped SnO2

2014 ◽  
Vol 716-717 ◽  
pp. 20-23
Author(s):  
Min Xu
Keyword(s):  
Density Functional Theory ◽  
Optical Properties ◽  
Absorption Spectrum ◽  
Electronic Structure ◽  
Optical Absorption ◽  
Band Structure ◽  
Density Functional ◽  
Density Of State ◽  
Functional Theory ◽  
Reflectivity Spectrum

based on Density Functional Theory, we investigated the optical structures and the electronic properties of Cu doped SnO2with density of 12.5%, including band structure, the density of state (dos), Dielectric function and optical absorption spectrum. The results show that Fermi level access conduction band gradually with the doped density. It has enhanced the electrical and metal property of material. The peaks of reflectivity spectrum and absorption spectrum correspond density of state.

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