Theoretical Studies of ZnO and Related MgxZn1-xO Alloy Band Structures

1998 ◽  
Vol 537 ◽  
Author(s):  
Walter R. L. Lambrecht ◽  
Sukit Limpijumnong ◽  
B. Segall
Keyword(s):  
Experimental Data ◽  
Band Gap ◽  
Valence Band ◽  
First Principles ◽  
Alloy System ◽  
Band Offset ◽  
Type I ◽  
Theoretical Studies ◽  
First Principles Calculations ◽  
Band Position

AbstractFirst principles calculations are carried out for ZnO, MgO and ZnMgO2 in various crystal structures. The nature of the valence band ordering in ZnO is shown to depend strongly on the Zn3d band position. MgO in the wurtzitic form is found to gave an unusual 5-fold coordiated structure. The band gap dependence in the alloy system is found to be in fair agreement with experimental data and the band-offset is predicted to be type I.

scholarly journals Theoretical Studies of ZnO and Related MgxZn1−xO Alloy Band Structures

1999 ◽  
Vol 4 (S1) ◽  
pp. 582-587 ◽  
Author(s):  
Walter R. L. Lambrecht ◽  
Sukit Limpijumnong ◽  
B. Segall
Keyword(s):  
Experimental Data ◽  
Band Gap ◽  
Valence Band ◽  
First Principles ◽  
Alloy System ◽  
Band Offset ◽  
Type I ◽  
Theoretical Studies ◽  
First Principles Calculations ◽  
Band Position

First principles calculations are carried out for ZnO, MgO and ZnMgO2 in various crystal structures. The nature of the valence band ordering in ZnO is shown to depend strongly on the Zn3d band position. MgO in the wurtzitic form is found to gave an unusual 5-fold coordiated structure. The band gap dependence in the alloy system is found to be in fair agreement with experimental data and the band-offset is predicted to be type I.

Electric fields at the SiC/AlN and SiC/GaN polar interfaces

2000 ◽  
Vol 639 ◽  
Author(s):  
Morad Rouhani Laridjani ◽  
Pierre Masri ◽  
Jacek A. Majewski
Keyword(s):  
Electronic Properties ◽  
Valence Band ◽  
Electric Fields ◽  
Mixed Layer ◽  
First Principles ◽  
Type I ◽  
First Principles Calculations ◽  
Interface Charges ◽  
Structural And Electronic Properties

ABSTRACTWe present first-principles calculations of structural and electronic properties of heterovalent SiC/AlN and SiC/GaN heterostructures with wurtzite AlN and GaN films pseudomorphically grown on the 6H-SiC and 3C-SiC substrates along the c-axis. We have investigated reconstructed stoichiometric interfaces consisting of one mixed layer with various lateral arrangements. The preferred bonding configurations of the reconstructed interfaces are found to be Si-N and Ga-C. The calculated valence band discontinuities for SiC/AlN and SiC/GaN heterostructures lie in the range of 1.5 - 2.3 eV and 0.4 - 1.4 eV, respectively. The SiC/AlN heterostructures are predicted to be of type I, whereas SiC/GaN heterostructures can be of type I or II. The polarization induced interface charges are of the order of 4.8 × 1012cm−2 and 0.7 × 1012 cm−2 in SiC/AlN and SiC/GaN junctions, respectively.

Stability and Band Offsets of SiC/GaN, SiC/AlN, and AlN/GaN Heterostructures

1996 ◽  
Vol 449 ◽  
Author(s):  
J. A. Majewski ◽  
M. Städele ◽  
P. Vogl
Keyword(s):  
Valence Band ◽  
First Principles ◽  
Valence Band Maximum ◽  
Type I ◽  
First Principles Calculations ◽  
Band Offsets ◽  
Structural And Electronic Properties ◽  
Transitivity Rule ◽  
Gan Heterostructure ◽  
Mixed Layers

ABSTRACTWe present first-principles calculations of structural and electronic properties of heterova-lent SiC/GaN, SiC/AIN, and isovalent AIN/GaN heterostructures that are grown pseudo-morphically on (001) or (110) SiC substrates. For the polar interfaces, we have investigated reconstructed stoichiometric interfaces consisting of one and two mixed layers with lateral c(2 × 2), 2 × 1, 1 × 2, and 2 × 2 arrangements. The preferred bonding configurations of the reconstructed interfaces are found to be Si-N and Ga-C. With respect to vacuum, the valence band maximum is found to be highest in SiC and lowest in A1N. In these systems, the valence band offsets deviate substantially from the transitivity rule and depend sensitively on the microscopic details of the interface geometry. The SiC/AIN and AIN/GaN heterostructures are predicted to be of type I, whereas SiC/GaN heterostructure can be of type I or II.

Strain-induced semimetal-to-semiconductor transition and indirect-to-direct band gap transition in monolayer 1T-TiS2

RSC Advances ◽  
2015 ◽  
Vol 5 (102) ◽  
pp. 83876-83879 ◽  
Author(s):  
Chengyong Xu ◽  
Paul A. Brown ◽  
Kevin L. Shuford
Keyword(s):  
Band Gap ◽  
Electronic Properties ◽  
Plane Strain ◽  
Material Properties ◽  
First Principles ◽  
Tensile Strain ◽  
First Principles Calculations ◽  
Direct Band Gap ◽  
Direct Band ◽  
Uniform Plane

We have investigated the effect of uniform plane strain on the electronic properties of monolayer 1T-TiS2using first-principles calculations. With the appropriate tensile strain, the material properties can be transformed from a semimetal to a direct band gap semiconductor.

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.

First-Principles Calculations of Titanium Dopants in Alumina

2005 ◽  
Vol 475-479 ◽  
pp. 3095-3098
Author(s):  
Katsuyuki Matsunaga ◽  
Teruyasu Mizoguchi ◽  
Atsutomo Nakamura ◽  
Takahisa Yamamoto ◽  
Yuichi Ikuhara
Keyword(s):  
Band Gap ◽  
First Principles ◽  
Electronic Structures ◽  
First Principles Calculations ◽  
Pseudopotential Calculations ◽  
Formation Energies

First-principles pseudopotential calculations were performed to investigate atomic and electronic structures of titanium (Ti) dopants in alumina (Al2O3). It was found that a substitutional Ti3+ defect induced an extra level occupied by one electron within the band gap of Al2O3. When two or more substitutional Ti3+ defects were located closely to each other, the defect-induced levels exhibited strong bonding interactions, and their formation energies decreased with increasing numbers of Ti3+ defects. This indicates that association and clustering of substitutional Ti3+ defects in Al2O3 can take place due to the interaction of the defect-induced levels.

New Pt-based Superalloy System Designed from First Principles

2008 ◽  
Vol 1128 ◽  
Author(s):  
Vsevolod I. Razumovskiy ◽  
Eyvaz I. Isaev ◽  
Andrei V. Ruban ◽  
Pavel A. Korzhavyi
Keyword(s):  
Elastic Properties ◽  
First Principles ◽  
Defect Formation ◽  
Alloy System ◽  
First Principles Calculations ◽  
Phonon Spectra ◽  
Ultrahigh Temperature ◽  
New Generation ◽  
Formation Energies ◽  
Temperature Applications

AbstractPt-Sc alloys with the γ-γ′ microstructure are proposed as a basis for a new generation of Pt-based superalloys for ultrahigh-temperature applications. This alloy system was identified on the basis of first-principles calculations. Here we discuss the prospects of the Pt-Sc alloy system on the basis of calculated elastic properties, phonon spectra, and defect formation energies.

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