First principles calculations of electronic and optical properties of Zr-doped La2O3

2013 ◽  
Vol 91 (10) ◽  
pp. 801-807 ◽  
Author(s):  
Changpeng Chen ◽  
Jianxiong Xie ◽  
Shuibo Chen ◽  
Yanli Li
Keyword(s):  
Optical Properties ◽  
Band Gap ◽  
First Principles ◽  
Density Functional ◽  
Visible Region ◽  
Potential Candidate ◽  
First Principles Calculations ◽  
Additional Absorption ◽  
Level Shifts ◽  
Calculation Results

Based on the density functional pseudopotential method, the structural properties, the band structure, the density of states, and the optical properties of pure and Zr-doped La2O3 were calculated. The calculation results indicate that the defect of La (Zr) exists steadily with a certain solubility. Zr substitution of the La sites induces effective reduction of the band gap of La2O3, the band gap being continuously reduced when increasing Zr doping level. The Fermi energy level shifts to the conduction band and exhibits metal-like characteristic after the Zr atom is introduced. The calculated optical properties indicate that red shifts are revealed in both the imaginary part of the dielectric function and the absorption spectra corresponding to the change of band gaps. Moreover, additional absorption is observed in the visible region, which implies that Zr-doped La2O3 might be a potential candidate for photoelectrical application. The calculation results are consistent with experimental results that have been reported.

First Principles Calculations of Electronic and Optical Properties of Al1-xLaxN

2011 ◽  
Vol 393-395 ◽  
pp. 110-113
Author(s):  
Chang Peng Chen ◽  
Mei Lan Qi
Keyword(s):  
Optical Properties ◽  
Band Gap ◽  
Density Functional ◽  
Density Functional Method ◽  
High Energy ◽  
Functional Method ◽  
Absorption Region ◽  
Additional Absorption ◽  
Calculation Results ◽  
La Substitution

Based on the density functional method, the electronic structures and the optical properties for Al1-xLaxN(x=0, 0.0625, 0.125, 0.1875) are comparatively investigated in detail. The calculation results indicate that La substitution of the Al sites induces effective reduction of the band gap of AlN, and the band gap being continuously reduced when increasing La doping level. With the increase of La concentration, both the imaginary part of dielectric function and the absorption spectrum show red-shift corresponding to the change of band gaps. Moreover, additional absorption peaks are observed above the absorption edge in the high-energy range which widens the absorption region.

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

2013 ◽  
Vol 562-565 ◽  
pp. 1166-1170 ◽  
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.

Electronic Structure and Optical Properties of La or In Doped SnO2: First-Principles Calculations

2011 ◽  
Vol 393-395 ◽  
pp. 80-83
Author(s):  
Chang Peng Chen ◽  
Mei Lan Qi
Keyword(s):  
Optical Properties ◽  
First Principles ◽  
Electronic Structures ◽  
Density Functional ◽  
Density Functional Method ◽  
Functional Method ◽  
First Principles Calculations ◽  
Effective Reduction ◽  
Calculation Results ◽  
Impurity Elements

Based on the density functional method, the electronic structures and the optical properties for pure and La or In doped SnO2 are comparatively investigated in detail. The calculation results indicate that both the doping of La and the doping of In induce effective reduction of the band gap of SnO2, the impurity elements form new highly localized impurity energy level at the top of the valence band near the Fermi level. The interaction between electrons changed after doping which leads to the change of electrical properties .Meanwhile, red shifts are revealed in both the imaginary part of dielectric function and the absorption spectra corresponding to the change of band gaps

scholarly journals Electronic and optical properties of vacancy ordered double perovskites A2BX6 (A = Rb, Cs; B = Sn, Pd, Pt; and X = Cl, Br, I): a first principles study

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Muhammad Faizan ◽  
K. C. Bhamu ◽  
Ghulam Murtaza ◽  
Xin He ◽  
Neeraj Kulhari ◽  
...  
Keyword(s):  
Optical Properties ◽  
Band Gap ◽  
First Principles ◽  
Density Functional ◽  
Perovskite Solar Cells ◽  
Dielectric Constants ◽  
Maximum Efficiency ◽  
Exchange Potential ◽  
Double Perovskites ◽  
Electronic And Optical Properties

AbstractThe highly successful PBE functional and the modified Becke–Johnson exchange potential were used to calculate the structural, electronic, and optical properties of the vacancy-ordered double perovskites A2BX6 (A = Rb, Cs; B = Sn, Pd, Pt; X = Cl, Br, and I) using the density functional theory, a first principles approach. The convex hull approach was used to check the thermodynamic stability of the compounds. The calculated parameters (lattice constants, band gap, and bond lengths) are in tune with the available experimental and theoretical results. The compounds, Rb2PdBr6 and Cs2PtI6, exhibit band gaps within the optimal range of 0.9–1.6 eV, required for the single-junction photovoltaic applications. The photovoltaic efficiency of the studied materials was assessed using the spectroscopic-limited-maximum-efficiency (SLME) metric as well as the optical properties. The ideal band gap, high dielectric constants, and optimum light absorption of these perovskites make them suitable for high performance single and multi-junction perovskite solar cells.

scholarly journals First-Principles Study on the Stabilities, Electronic and Optical Properties of GexSn1-xSe Alloys

Nanomaterials ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 876 ◽  
Author(s):  
Qi Qian ◽  
Lei Peng ◽  
Yu Cui ◽  
Liping Sun ◽  
Jinyan Du ◽  
...  
Keyword(s):  
Optical Properties ◽  
Solar Cells ◽  
Band Gap ◽  
Electronic Properties ◽  
First Principles ◽  
Future Application ◽  
First Principles Calculations ◽  
Electronic And Optical Properties ◽  
Direct Bandgap ◽  
The Future

We systematically study, by using first-principles calculations, stabilities, electronic properties, and optical properties of GexSn1-xSe alloy made of SnSe and GeSe monolayers with different Ge concentrations x = 0.0, 0.25, 0.5, 0.75, and 1.0. Our results show that the critical solubility temperature of the alloy is around 580 K. With the increase of Ge concentration, band gap of the alloy increases nonlinearly and ranges from 0.92 to 1.13 eV at the PBE level and 1.39 to 1.59 eV at the HSE06 level. When the Ge concentration x is more than 0.5, the alloy changes into a direct bandgap semiconductor; the band gap ranges from 1.06 to 1.13 eV at the PBE level and 1.50 to 1.59 eV at the HSE06 level, which falls within the range of the optimum band gap for solar cells. Further optical calculations verify that, through alloying, the optical properties can be improved by subtle controlling the compositions. Since GexSn1-xSe alloys with different compositions have been successfully fabricated in experiments, we hope these insights will contribute to the future application in optoelectronics.

Regulating the electronic and optical properties of GaN/InN core/shell nanowires: A first-principles study

2020 ◽  
Vol 34 (25) ◽  
pp. 2050214 ◽  
Author(s):  
Chang Liu ◽  
Enling Li ◽  
Tuo Peng ◽  
Kaifei Bai ◽  
Yanpeng Zheng ◽  
...  
Keyword(s):  
Optical Properties ◽  
First Principles ◽  
Core Shell ◽  
First Principles Calculations ◽  
Electronic And Optical Properties ◽  
Gan Nanowires ◽  
The Core ◽  
Light Region ◽  
Calculation Results ◽  
Shell Nanowires

In this paper, electronic and optical properties of GaN/InN core/shell nanowires (CSNWs) have been theoretically investigated through the first principles calculations. The binding energy of In and N atoms on surface of six crystal planes along the [Formula: see text]-axis of GaN nanowires are all negative, which indicate that In and N atoms can be effectively deposited on the surface of GaN nanowires and preparing GaN/InN CSNWs is feasible theoretically. Calculation results of electronic properties indicate that the core/shell ratio and diameter of GaN/InN CSNWs have significant effect on the band structure, bandgap can be effectively adjusted when keeping the number of GaN layers unchanged and changing the number of InN layers. Moreover, with the increase in the number of InN layers, the absorption spectrum of GaN/InN CSNW has significant redshift and few weak absorption peaks appear in the visible light region.

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.

First-principles studies on electronic structures and optical properties of two-dimensional Sn1−xTi(Zr)xS2 alloys

2018 ◽  
Vol 32 (07) ◽  
pp. 1850092 ◽  
Author(s):  
Dandan Li ◽  
Juan Du ◽  
Qian Zhang ◽  
Congxin Xia ◽  
Shuyi Wei
Keyword(s):  
Optical Properties ◽  
Band Gap ◽  
First Principles ◽  
Electronic Structures ◽  
Threshold Energy ◽  
Ternary Alloys ◽  
Two Dimensional ◽  
First Principles Calculations ◽  
Experimental Conditions ◽  
Part Formula

Through first-principles calculations we study the electronic structures and optical properties of two-dimensional (2D) Sn[Formula: see text]Ti(Zr)[Formula: see text]S2 alloys. The results indicate that the band gap value of Sn[Formula: see text]Ti(Zr)[Formula: see text]S2 alloys is decreased continuously when Ti(Zr) concentration is increased, which is very beneficial to optoelectronic devices applications. Moreover, the static dielectric constant is increased when the Ti(Zr) concentration is increased in the 2D Sn[Formula: see text]Ti(Zr)[Formula: see text]S2 alloys. In addition, we also calculate the imaginary part [Formula: see text] dispersion of Sn[Formula: see text]Ti(Zr)[Formula: see text]S2 alloys along the plane with different Ti(Zr) concentrations. The threshold energy values decrease with increasing Ti(Zr) concentrations in the Sn[Formula: see text]Ti(Zr)[Formula: see text]S2 ternary alloys. Moreover, the calculations of formation energy also indicate that these 2D alloys can be fabricated under some experimental conditions. These results suggest that Ti(Zr) substituting Sn atom is an efficient way to tune the band gap and optical properties of 2D SnS2 nanosheets.

scholarly journals First–Principles Investigation of the Structural, Elastic, Electronic, and Optical Properties of α– and β–SrZrS3: Implications for Photovoltaic Applications

Materials ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 978
Author(s):  
Henry Igwebuike Eya ◽  
Esidor Ntsoenzok ◽  
Nelson Y. Dzade
Keyword(s):  
Optical Properties ◽  
First Principles ◽  
Density Functional ◽  
Visible Region ◽  
Charge Carriers ◽  
Band Gaps ◽  
Strong Light ◽  
Electronic And Optical Properties ◽  
Optical Absorbance ◽  
Effective Masses

Transition metal perovskite chalcogenides are attractive solar absorber materials for renewable energy applications. Herein, we present the first–principles screened hybrid density functional theory analyses of the structural, elastic, electronic and optical properties of the two structure modifications of strontium zirconium sulfide (needle–like α–SrZrS3 and distorted β–SrZrS3 phases). Through the analysis of the predicted electronic structures, we show that both α– and β–SrZrS3 materials are direct band gaps absorbers, with calculated band gaps of 1.38, and 1.95 eV, respectively, in close agreement with estimates from diffuse–reflectance measurements. A strong light absorption in the visible region is predicted for the α– and β–SrZrS3, as reflected in their high optical absorbance (in the order of 105 cm−1), with the β–SrZrS3 phase showing stronger absorption than the α–SrZrS3 phase. We also report the first theoretical prediction of effective masses of photo-generated charge carriers in α– and β–SrZrS3 materials. Predicted small effective masses of holes and electrons at the valence, and conduction bands, respectively, point to high mobility (high conductivity) and low recombination rate of photo-generated charge carriers in α– and β–SrZrS3 materials, which are necessary for efficient photovoltaic conversion.

Electronic Structure, Effective Masses and Optical Properties of Monoclinic HfO2 from First-Principles Calculations

2011 ◽  
Vol 216 ◽  
pp. 341-344 ◽  
Author(s):  
Qi Jun Liu ◽  
Zheng Tang Liu ◽  
Li Ping Feng
Keyword(s):  
Optical Properties ◽  
Electronic Structure ◽  
Band Structure ◽  
First Principles ◽  
Density Functional ◽  
First Principles Calculations ◽  
Functional Theory ◽  
Effective Masses ◽  
Indirect Band Gap ◽  
Calculated Equilibrium

Electronic structure, effective masses and optical properties of monoclinic HfO2were studied using the plane-wave ultrasoft pseudopotential technique based on the first-principles density-functional theory (DFT). The calculated equilibrium lattice parameters are in agreement with the previous works. From the band structure, the effective masses and optical properties are obtained. The calculated band structure shows that monoclinic HfO2has indirect band gap and all of the effective masses of electrons and holes are less than that of a free electron. The peaks position distributions of imaginary parts of the complex dielectric function have been explained according to the theory of crystal-field and molecular-orbital bonding.

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