Electronic Structures of Wide Band-Gap (AlN)m(GaN)n[001] Superlattices

1995 ◽  
Vol 395 ◽  
Author(s):  
Z.-J. Tian ◽  
M.W.C. Dharma-Wardana ◽  
L.J. Lewis
Keyword(s):  
Band Gap ◽  
Electronic Band Structure ◽  
Wide Band ◽  
Orbital Method ◽  
Full Potential ◽  
Wide Band Gap ◽  
Electronic Band ◽  
Level Shifts ◽  
Direct Band ◽  
Near Term

ABSTRACTWide bandgap III-V nitrides, such as GaN and AlN, have become topical in the near-term technology of blue lasers. We report detailed electronic band-structure calculations for (AlN)m(GaN)n [001] zinc-blende superlattices (SL), with m + n ≤ 12, using the all-electron full-potential linear-muffin-tin-orbital method. For n ≥ 3, the SL are found to have a direct band gap. For n ≤ 2 and m ≥ 3, all the band gaps are indirect. In ultrathin SL, m ≤ 3 and n ≤ 2, only (m, n)= (3,1) is found to have an indirect gap. The band offsets are estimated by calculating the core-level shifts of nitrogen atoms in the central planes of the GaN and A1N layers. The calculated densities of states, electron- and hole- effective masses (m), etc., as a function of m and n, are reported; a remarkable dependence of m on the number of layers is revealed.

scholarly journals Li2CaGeO4 – Wide Band Gap Semiconductor: First Principles Investigation of the Structural, Electronic, Optical and Elastic Properties

2020 ◽  
Author(s):  
Saadi Berri
Keyword(s):  
Elastic Anisotropy ◽  
Electronic Band Structure ◽  
Wide Band ◽  
Full Potential ◽  
Wide Band Gap ◽  
Pressure Derivative ◽  
Electronic Band ◽  
Augmented Plane Wave ◽  
Derived Properties ◽  
Linearized Augmented Plane Wave

The electronic structure and some of its derived properties of Li2CaGeO4 compound have been investigated. The calculations have been performed using the full-potential linearized augmented plane wave plus local orbitals method and ultra-soft pseudo-potentials . The optimized lattice parameters are found to be ingood accord with experiment. Features such as bulk modulus and its pressure derivative, electronic band structure and density of states are reported. The elastic anisotropy of the crystal is discussed and visualized. Moreover, the optical properties reveal that Li2CaGeO4 compound are suitable candidates for optoelectronic devices in the visible and ultraviolet (UV) regions.

Electronic Structure of Wide-Band-Gap Chalcopyrites

1992 ◽  
Vol 281 ◽  
Author(s):  
A. Petukhov ◽  
W. R. L. Lambrecht ◽  
B. Segall
Keyword(s):  
Electronic Structure ◽  
Band Gap ◽  
Structural Parameters ◽  
Wide Band ◽  
Orbital Method ◽  
Wide Band Gap ◽  
Electronic Band ◽  
Lattice Constants ◽  
Cohesive Energies ◽  
Electronic Band Structures

ABSTRACTElectronic band structures, equilibrium lattice constants and structural parameters, cohesive energies, and bulk moduli calculated by means of the linear-muffin-tin orbital method are presented for BeSiN2, MgSiN2 and MgSiP2 chalcopyrites. The relationships of these compounds to the “parent” III-V compounds are clarified.

OPTICAL ABSORPTION BEHAVIOR OF Co (II) ION DOPED PVA ASSISTED CdSe NANOPARTICLES

2013 ◽  
Vol 22 ◽  
pp. 346-350
Author(s):  
K. RAVINDRANADH ◽  
R. V. S. S. N. RAVIKUMAR ◽  
M. C. RAO
Keyword(s):  
Band Gap ◽  
Room Temperature ◽  
Urbach Energy ◽  
Wavelength Region ◽  
Wide Band ◽  
Cdse Nanoparticles ◽  
Poly Vinyl Alcohol ◽  
Wide Band Gap ◽  
Direct Band ◽  
Bulk Band

CdSe is an important II-VI, n-type direct band gap semiconductor with wide band gap (bulk band gap of 2.6 eV) and an attractive host for the development of doped nanoparticles. Poly vinyl alcohol (PVA) is used as a capping agent to stabilize the CdSe nanoparticles. The optical properties of Co (II) ion doped PVA capped CdSe nanoparticles grown at room temperature are studied in the wavelength region of 200-1400 nm. The spectrum of Co (II) ion doped PVA capped CdSe nanoparticles exhibit five bands at 1185, 620, 602, 548 and 465 nm (8437, 16125, 16607, 18243 and 21499 cm-1). The bands observed at 1185, 548 and 465 nm are correspond to the three spin allowed transitions 4T1g (F) → 4T2g (F), 4T1g (F) → 4A2g (F) and 4T1g (F) → 4T1g (P) respectively. The other bands observed at 602 nm and 620 nm are assigned to spin forbidden transitions 4T1g (F) → 2T2g (G), 4T1g (F) → 2T1g (G) . The small value of the Urbach energy indicates greater stability of the prepared sample.

STRUCTURAL PHASE TRANSITION, ELASTIC AND ELECTRONIC PROPERTIES OF CuXSe2(X = In, Ga) CHALCOPYRITE

2012 ◽  
Vol 19 (02) ◽  
pp. 1250021 ◽  
Author(s):  
T. BOUGUETAIA ◽  
B. ABIDRI ◽  
B. BENBAHI ◽  
D. RACHED ◽  
S. HIADSI ◽  
...  
Keyword(s):  
Band Gap ◽  
Electronic Properties ◽  
Density Functional ◽  
Local Density ◽  
Structural Phase ◽  
Theoretical Data ◽  
Young Modulus ◽  
Orbital Method ◽  
Full Potential ◽  
Direct Band

The structural, elastic and electronic properties of chalcopyrite compound CuInSe2 and CuGaSe2 have been investigated using the full-potential linearized muffin-tin orbital method (FP-LMTO) within the frame of density functional theory (DFT). In this approach, the local density approximation is used for the exchange-correlation potential using Perdew–Wang parametrization. The equilibrium lattice parameters, bulk modulus, transition pressure, elastic constants and their related parameters such as Poisson's ratio, Young modulus, shear modulus and Debye temperature were calculated and compared with available experimental and theoretical data. They are in reasonable agreement. In this paper the electronic properties are treated with GGA + U approach, which brings out the important role played by the d-state of noble metal (Cu) and give the correct nature of the energy band gap. Our obtained results show that both compounds exhibit semi-conductor behaviour with direct band gap.

Ab initio Electronic Band Structure Calculations for Beryllium Chalcogenides

1998 ◽  
Vol 12 (19) ◽  
pp. 1975-1984 ◽  
Author(s):  
G. Kalpana ◽  
G. Pari ◽  
A. Mookerjee ◽  
A. K. Bhattacharyya
Keyword(s):  
Bulk Modulus ◽  
Band Gap ◽  
Structural Transition ◽  
Electronic Band Structure ◽  
Local Density ◽  
Structural Phase ◽  
Experimental Results ◽  
Orbital Method ◽  
Electronic Band ◽  
Indirect Band Gap

The first principles tight-binding linear muffin-tin orbital method within the local density approximation (LDA) has been used to calculate the ground state properties structural phase transition and pressure dependence of the band gap of BeS, BeSe and BeTe. We have calculated the energy-volume relations for these compounds in the B3 and B8 phases. The calculated lattice parameters, bulk modulus and the pressure-volume relation were found to be in good agreement with the recent experimental results. We have also calculated the cohesive energy for them and they are consistent with the bulk modulus. The calculated B3 to B8 structural transition pressure for BeS, BeS and BeTe agree well with the experimental results. Our calculations show that these compounds are indirect band gap (Γ-X) semiconductors at ambient conditions. The calculated band gap values are found to be underestimated by 20–30% which is due to the usage of LDA. After the structural transition to the B8 phase BeS continues to be indirect band gap semiconductor and ultimately it becomes metallic above 100 GPa. BeSe and BeTe are metallic at B3 to B8 structural transition.

STRUCTURAL, ELASTIC, ELECTRONIC, CHEMICAL BONDING AND OPTICAL PROPERTIES OF M2Se (M = Li, Na, K, Rb) THROUGH FIRST PRINCIPLE STUDY

2013 ◽  
Vol 27 (30) ◽  
pp. 1350170 ◽  
Author(s):  
ROSHAN ALI ◽  
R. KHANATA ◽  
BIN AMIN ◽  
G. MURTAZA ◽  
S. BIN OMRAN
Keyword(s):  
Optical Properties ◽  
Band Gap ◽  
Chemical Bonding ◽  
Energy Band ◽  
Electronic Band Structure ◽  
Full Potential ◽  
Energy Band Gap ◽  
Electronic Band ◽  
Direct Energy ◽  
Metal Selenides

Structural, elastic, electronic and optical properties as well as chemical bonding of the binary alkali metal selenides M 2 Se ( M = Li , Na , K , Rb ) were calculated using the full potential linearized augmented plane method. From the elastic constants it is inferred that these compounds are brittle in nature. The results of the electronic band structure show that Na 2 Se has a direct energy band gap (Γ-Γ), Li 2 Se has an indirect energy band gap (Γ- X), while K 2 Se and Rb 2 Se have an indirect energy band gap (X-Γ). Analysis of the charge distribution plots reveals a dominated ionic bonding in the herein studied compounds. Additionally, we have calculated the optical properties, namely, the real and the imaginary parts of the dielectric function, refractive index, extinction coefficient, optical conductivity and reflectivity for radiation up to 30.0 eV. All these compounds have direct energy band gap greater than 3.1 eV suggesting their use for manufacturing high frequency devices.

Flexible Modulation of Electronic Band Structures of Wide Band Gap GaN Semiconductors Using Bioinspired, Nonbiological Helical Peptides

2017 ◽  
Vol 28 (2) ◽  
pp. 1704034 ◽  
Author(s):  
Sven Mehlhose ◽  
Nataliya Frenkel ◽  
Hirotaka Uji ◽  
Sara Hölzel ◽  
Gesche Müntze ◽  
...  
Keyword(s):  
Band Gap ◽  
Wide Band ◽  
Wide Band Gap ◽  
Band Structures ◽  
Electronic Band ◽  
Helical Peptides ◽  
Electronic Band Structures

First-principles calculations on structure and electronic properties of α-zirconium hydrogen phosphate

MRS Advances ◽  
2019 ◽  
Vol 4 (50) ◽  
pp. 2699-2707
Author(s):  
V. W. Elloh ◽  
Soni Mishra ◽  
A. Yaya ◽  
Abhishek Kumar Mishra
Keyword(s):  
Band Gap ◽  
First Principles ◽  
Density Functional ◽  
Semiconductor Device ◽  
Electronic Band Structure ◽  
Structural Parameters ◽  
Hydrogen Phosphate ◽  
Electronic Band ◽  
Potential Applications ◽  
Direct Band

AbstractLayered zirconium hydrogen phosphate intercalation compounds can be easily tuned, leading to potential applications in many fields, specifically by introducing them in different polymeric composites as nanofillers. Employing first-principles density functional theory based calculations, we have investigated ground state electronic structure properties of α-zirconium hydrogen phosphate (α-ZrP). We discuss the structure and electronic band structure, where projected density of states calculations have been discussed to understand the different atomic orbitals contributions to electronic bands. ZrP has numerous properties of interest for use in many semiconductor device structures, specifically, layered zirconium hydrogen phosphate has substantial promise for both optical devices and for high power electronics due to its large direct band gap. Our structural calculations suggest that layered zirconium hydrogen phosphate exhibits monoclinic structure. The calculated structural parameters and band gap are in good agreement with available experimental data.

Methylamine Growth of SiCN Films Using ECR-CVD

1999 ◽  
Vol 606 ◽  
Author(s):  
C.-Y. Wen ◽  
J.-J. Wu ◽  
H.J. Lo ◽  
L.C. Chen ◽  
K.H. Chen ◽  
...  
Keyword(s):  
Carbon Source ◽  
Carbon Content ◽  
Band Gap ◽  
Gas Phase ◽  
Wide Band ◽  
Point Of View ◽  
Nucleation Density ◽  
Wide Band Gap ◽  
Direct Band ◽  
Lower Carbon

AbstractContinuous polycrystalline SiCN films with high nucleation density have been successfully deposited by using CH3NH2, as carbon source gas in an ECR-CVD reactor. Fom the kinetic point of view, using CH3NH2, as carbon source could provide more abundant active carbon species in the gas phase to enhance the carbon incorporation in the SiCN films. The compositions of the SiCN films analyzed from Rutherford Backscattering Spectroscopy showed that higher [CH3NH2,]/[SiH4] ratio led to higher carbon content in the films. Moreover, a lower carbon content was measured when the film was deposited at higher substrate temperature. The direct band gap of the aforementioned SiCN films determined using PzR is around 4.4 eV, indicating a wide band gap material for blue-UV optoelectronics.

scholarly journals Structural, Electronic and Optical Properties of InAs Phases: By GGA-PBG and GGA-EV Approximations

2017 ◽  
Vol 41 (3) ◽  
pp. 172-182
Author(s):  
Leila Sohrabi ◽  
Arash Boochani ◽  
S. Ali Sebt ◽  
S. Mohammad Elahi
Keyword(s):  
Optical Properties ◽  
Band Gap ◽  
Density Functional ◽  
Photonic Devices ◽  
Optical Parameters ◽  
Full Potential ◽  
Electronic Band ◽  
Electronic And Optical Properties ◽  
Direct Band ◽  
Electronic Band Gap

Structural, electronic and optical properties of InAs are investigated in the zinc-blende (ZB), rock-salt (RS) and wurtzite (WZ) phases using the full potential linearised augmented plane wave method in the framework of density functional theory (DFT). The electronic band gap of the ZB and WZ phases are improved and in good agreement with experiments by GGA-EV approximation. This compound has a direct band gap in the ZB and WZ phases in point at the centre Brillouin zone and in the RS phase the conduction band crosses towards the valence band and has metallic behaviour. Also, the optical parameters such as the real and imaginary parts of epsilon, energy loss, and the refraction and reflection indices of all the phases are calculated and compared. The calculated optical properties of InAs have promising applications such as the design of optoelectronic and photonic devices.

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