scholarly journals Electronic Structure of Rock Salt Alloys of Rare Earth and Group III Nitrides

Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 4997
Author(s):  
Maciej J. Winiarski
Keyword(s):  
First Principles ◽  
Electronic Structures ◽  
Group Iii Nitrides ◽  
Linear Increase ◽  
Lattice Parameters ◽  
Ionic Radii ◽  
Band Gap Engineering ◽  
Group Iii ◽  
Cubic Lattice ◽  
P Type

Lattice parameters and electronic properties of RE1−xAxN alloys, where RE = Sc, Y, Lu and A = Al, Ga, and In, have been derived from first principles. The materials are expected to exhibit a linear decrease in cubic lattice parameters and a tendency to a linear increase in band gaps as a function of composition. These effects are connected with a strong mismatch between ionic radii of the RE and group III elements, which leads to chemical pressure in the mixed RE and group III nitrides. The electronic structures of such systems are complex, i.e., some contributions of the d- and p-type states, coming from RE and A ions, respectively, are present in their valence band regions. The findings discussed in this work may encourage further experimental efforts of band gap engineering in RE-based nitrides via doping with group III elements.

First-principles study of the structural and thermoelectric properties of Y-doped α-SrSi2

2022 ◽  
Author(s):  
Masato Yamaguchi ◽  
Daishi Shiojiri ◽  
Tsutomu Iida ◽  
Naomi Hirayama ◽  
Yoji IMAI
Keyword(s):  
Thermoelectric Properties ◽  
First Principles ◽  
Electronic Structures ◽  
Narrow Band ◽  
Hybrid Functional ◽  
Promising Candidate ◽  
Functional Theory ◽  
Seebeck Coefficients ◽  
Increasing Temperature ◽  
P Type

Abstract The narrow-gap semiconductor α-SrSi2 is a promising candidate for low-temperature thermoelectric applications with low environmental load. The only experimental report in which α-SrSi2 is reported to have n-type conductivity is one where it had been doped with yttrium. To further clarify the effects of impurities, theoretical studies are needed. The α-SrSi2 has a very narrow band gap (~13–35 meV), causing difficulties in the accurate calculation of the electronic and thermoelectric properties. In our previous study, we overcame this problem for undoped α-SrSi2 using hybrid functional theory. We used this method in this study to investigate the structures, energetic stabilities, electronic structures, and thermoelectric properties of Y-doped α-SrSi2. The results indicate that substitution at Sr-sites is energetically about two times more stable than that at Si-sites. Furthermore, negative Seebeck coefficients were obtained at low temperatures and reverted to p-type with increasing temperature, which is consistent with the experimental results.

scholarly journals Estimation of Lattice Constants and Band Gaps of Group-III Nitrides using Local and Semi Local Functionals

2018 ◽  
Vol 34 (4) ◽  
pp. 2137-2143 ◽  
Author(s):  
Sandeep Arora ◽  
Dharamvir Singh Ahlawat ◽  
Dharambir Singh
Keyword(s):  
Band Gap ◽  
Local Density ◽  
Group Iii Nitrides ◽  
Lattice Parameters ◽  
Exchange Potential ◽  
Generalized Gradient ◽  
Group Iii ◽  
Lattice Constants ◽  
Mean Error ◽  
Gap Values

We performed the optimization of lattice constants of Group- III nitrides (InN, AlN, GaN) in wurtzite and Zinc blende structures using various semilocal exchange correlation functional in generalized gradient approximations (GGA) namely PBE, WC, PBEsol in addition to local density approximation (LDA) functional. We used these optimized lattice parameters to predict the band gap values using modified Becke Johnson exchange potential with original and improved parameterization as suggested by David Koller for semiconductors having band gap values below 7eV. Among the different functionals considered, PBEsol optimize the lattice parameters with smallest mean error (0.00639 Å) relative to experimental values, while WC approximation with a slightly greater value of mean error (0.00513 Å). It is shown that mBJLDA approximation improves the band gap for the materials studied when compared with LDA and GGA results. It is also shown that LDA optimized parameters with mBJLDA approximation, which leads to mean error of 0.162 eV reproduces the experimental band gap in most efficient way.

scholarly journals Critical Thermodynamic Conditions for the Formation of p-Type β-Ga2O3 with Cu Doping

Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5161
Author(s):  
Chuanyu Zhang ◽  
Zhibing Li ◽  
Weiliang Wang
Keyword(s):  
Oxygen Partial Pressure ◽  
First Principles ◽  
Electronic Structures ◽  
First Principles Calculation ◽  
Third Generation ◽  
Cu Doping ◽  
Thermodynamic Conditions ◽  
The Stability ◽  
P Type ◽  
Formation Energies

As a promising third-generation semiconductor, β-Ga2O3 is facing bottleneck for its p-type doping. We investigated the electronic structures and the stability of various Cu doped structures of β-Ga2O3. We found that Cu atoms substituting Ga atoms result in p-type conductivity. We derived the temperature and absolute oxygen partial pressure dependent formation energies of various doped structures based on first principles calculation with dipole correction. Then, the critical thermodynamic condition for forming the abovementioned substitutional structure was obtained.

Interfacial electronic features in methyl-ammonium lead iodide and p-type oxide heterostructures: new insights for inverted perovskite solar cells

2020 ◽  
Vol 22 (48) ◽  
pp. 28401-28413
Author(s):  
Adriana Pecoraro ◽  
Antonella De Maria ◽  
Paola Delli Veneri ◽  
Michele Pavone ◽  
Ana B. Muñoz-García
Keyword(s):  
Solar Cells ◽  
First Principles ◽  
Electronic Structures ◽  
Perovskite Solar Cells ◽  
Lead Iodide ◽  
Oxide Heterostructures ◽  
P Type

First-principles simulations unveil the interface electronic structures of MAPI/NiO and MAPI/CuGaO2 heterojunctions in inverted perovskite solar cells.

Elastic Constants and Related Properties of the Group III-Nitrides

1995 ◽  
Vol 395 ◽  
Author(s):  
Kwiseon Kim ◽  
Walter R. L. Lambrecht ◽  
B. Segall
Keyword(s):  
Elastic Constants ◽  
First Principles ◽  
Bond Angle ◽  
Local Density ◽  
Group Iii Nitrides ◽  
Internal Displacement ◽  
Orbital Method ◽  
Model Parameters ◽  
Full Potential ◽  
Group Iii

ABSTRACTThe elastic constants of the Group-III nitrides, c-BN, AlN and GaN were calculated from first-principles using the full-potential linear muffin-tin orbital method and local density approximation. The relation between the elatic constants in zincblende and wurtzite is studied by means of a tensor coordinate transformation approach. The latter combined with a correction for the internal displacement of the rotated tetrahedra is found to provide good results for the Ch11Ch12 and Ch44 but not for Ch13 and Ch33. These two require explicit calculations involving distortions along the c-axis. The calculations also provide information on the transverse optical phonons. By deriving Keating model parameters we show that BN is much stiffer against bond-angle distortions than the other nitrides.

Electron Properties of F, and N Doped Hematite: The Application for Photocatalysis

2012 ◽  
Vol 562-564 ◽  
pp. 298-301 ◽  
Author(s):  
Xiao Hong Wen ◽  
Hai Jun Pan
Keyword(s):  
Photocatalytic Activity ◽  
Water Splitting ◽  
Fermi Energy ◽  
First Principles ◽  
Electronic Structures ◽  
Shallow Donor ◽  
Electron Hole ◽  
Conduction Bands ◽  
P Type ◽  
Pec Water Splitting

To improve photocatalytic activity of hematite, the electronic structures of F, and N doped hematite were studied via the first-principles band calculations with GGA+U methods. By analyzing the band structures of pure and doped hematite, we showed that the significant acceptor levels were induced by N dopants, whereas F dopants created shallow donor levels and Fermi energy entered the conduction bands. Our findings proposed that p-type dopant N was in favor of realizing the expectation of producing hydrogen in the visible-light photoelectrochemical (PEC) water splitting without voltage bias, and n-type dopant F was helpful to solve the problem of recombination of photo-produced electron-hole pairs The results of our calculation should be applicable to the improvement of photocatalytic performances of hematite.

scholarly journals Anomalous doping effect in black phosphorene using first-principles calculations

2015 ◽  
Vol 17 (25) ◽  
pp. 16351-16358 ◽  
Author(s):  
Weiyang Yu ◽  
Zhili Zhu ◽  
Chun-Yao Niu ◽  
Chong Li ◽  
Jun-Hyung Cho ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
First Principles ◽  
Electronic Structures ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Doping Effect ◽  
First Principles Calculations ◽  
Functional Theory ◽  
Group Iii ◽  
Black Phosphorene

Using first-principles density functional theory calculations, we investigate the geometries, electronic structures, and thermodynamic stabilities of substitutionally doped phosphorene sheets with group III, IV, V, and VI elements.

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