First principles study of structural, electronic and optical properties of indium gallium nitride arsenide lattice matched to gallium arsenide (original) (raw)
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Optik, 2016
In this work, the first-principle calculations have been performed to predict the structural, electronic and optical properties of cubic InxGa1-xAs for 0≤x≤1, using 16-atom within the Full Potential Linearized Augmented Plane Wave (FP-LAPW) method based on Density Functional Theory (DFT) as implemented in WIEN2k computational code. The Local Density Approximation (LDA) and Wu-Cohen Generalized Gradient Approximation (WC-GGA) were employed as the exchange-correlation term to calculate the structural and electronic properties. Moreover, the Engel-Vosko GGA (EV-GGA) and the recently modified semi-local Becke-Johnson (mBJ) functional were also used to compute the electronic and optical properties in order to get some better degree of precision. The real and the imaginary parts of the dielectric function, refractive index, extinction coefficient, reflectivity, absorption coefficient and optical conductivity were calculated to discuss the linear optical properties of InxGa1-xAs alloys. The achieved results show a great potential utilization in optoelectronic devices especially in infrared applications.
Energy band gaps of Zn1−xMgxSySe1−y lattice matched to GaAs
Physica B: Condensed Matter, 2003
We report on theoretical study of the energy band gaps for the quaternary alloys Zn 1Àx Mg x S y Se 1Ày in conditions of lattice matching to GaAs substrates using simply the empirical pseudopotential method under the virtual crystal approximation which takes into account the effects of compositional disorder. Our results agree generally very well with the available experimental data. It is shown that the band-gap energies of Zn 1Àx Mg x S y Se 1Ày are expressed by the parabolic function of the composition considering the bowing parameter and that Zn 1Àx Mg x S y Se 1Ày can be a direct or an indirect semiconductor depending on the alloy composition. The Zn 0:35 Mg 0:65 S 0:6 Se 0:4 is predicted to meet requirement of the cladding layer for fabricating blue double heterostructure laser diodes using ZnS 0:06 Se 0:94 as the active layer.
Computational study of GaAs 1− x N x and GaN 1− y As y alloys and arsenic impurities in GaN
Journal of Physics: Condensed Matter, 2006
We have studied the structural and electronic properties of As-rich GaAs 1−x N x and N-rich GaN 1−y As y alloys in a large composition range using first-principles methods. We have systematically investigated the effect of the impurity atom configuration near both GaAs and GaN sides of the concentration range on the total energies, lattice constants and bandgaps. The N (As) atoms, replacing substitutionally As (N) atoms in GaAs (GaN), cause the surrounding Ga atoms to relax inwards (outwards), making the Ga-N (Ga-As) bond length about 15% shorter (longer) than the corresponding Ga-As (Ga-N) bond length in GaAs (GaN). The total energies of the relaxed alloy supercells and the bandgaps experience large fluctuations within different configurations and these fluctuations grow stronger if the impurity concentration is increased. Substituting As atoms with N in GaAs induces modifications near the conduction band minimum, while substituting N atoms with As in GaN modifies the states near the valence band maximum. Both lead to bandgap reduction, which is at first rapid but later slows down. The relative size of the fluctuations is much larger in the case of GaAs 1−x N x alloys. We have also looked into the question of which substitutional site (Ga or N) As occupies in GaN. We find that under Ga-rich conditions arsenic prefers the substitutional N site over the Ga site within a large range of Fermi level values.
FP-LAPW calculations of ground state properties for AlN, GaN and InN compounds
We present first-principals all-electrons total-energy calculations concerning structural and electronic properties for the group III-V zinc-blend-like compounds AlN, GaN and InN using the full-potential linearized augmented plane wave (FP-LAPW) approach within the density functional theory (D.F.T) in the local density approximation (L.D.A) and the generalized gradient approximation (G.G.A) for the exchange correlations functional. Moreover, we have calculated bulk properties, including ground-state energies, lattice parameters, bulk modulus, its derivatives, cohesive energy and band structures. We find that the GGA yields improved physical properties for bulk AlN compared to the LDA. For GaN and InN, essentially no improvement is found: the LDA exhibits over binding, whereas the GGA shows a tendency for under binding. The degree of under binding and the overestimation of lattice parameters as obtained within the GGA increase on going from InN to GaN. Band structures are found to be very similar within the LDA and the GGA, for AlN, GaN and InN, therefore, the GGA does not offer any significant advantages.
Theoretical Study of Group-III-Nitride Alloys
1996
Band gap bowing, structural relaxations, and energies of formation were calculated for the three pseudobinary nitride zincblende alloy systems AlGa , In-Ga and In-Al using the full-potential linearized muffin-tin orbital method. The cluster expansion and Connolly-Williams approaches were used to relate calculated band structures and energies of formation of ordered compounds to the behavior of disordered alloys. Effects of bond length and volume variation on those properties are discussed. An interpolation formula for the gap of the full pseudoternary Al x Ga y In z N system is proposed and tested by separate calculations. Extension of the results to the wurtzite alloys is discussed.
Band gap bowing in quaternary nitride semiconducting alloys
Applied Physics Letters, 2011
Structural properties of In x Ga y Al 1−x−y N alloys are derived from total-energy minimization within the local-density approximation ͑LDA͒. The electronic properties are studied by band structure calculations including a semiempirical correction for the "LDA gap error." The effects of varying the composition and atomic arrangements are examined using a supercell geometry. An analytical expression for the band gap is derived for the entire range of compositions. The range of ͑x, y͒ values for which In x Ga y Al 1−x−y N is lattice matched to GaN, and the ensuing energy gaps, are given. This range of available gaps becomes smaller when In atoms form clusters. Comparison to experimental data is made.
Transition energies and direct-indirect band gap crossing in zinc-blende Al_{x}Ga_{1−x}N
Physical Review B, 2013
The electronic and optical properties of zinc-blende (zb) Al x Ga 1−x N over the whole alloy composition range are presented in a joint theoretical and experimental study. Because zb-GaN is a direct (v → c) semiconductor and zb-AlN shows an indirect (v → X c) fundamental band gap, the ternary alloy exhibits a concentration-dependent direct-indirect band gap crossing point the position of which is highly controversial. The dielectric functions of zb-Al x Ga 1−x N alloys are measured employing synchrotron-based ellipsometry in an energy range between 1 and 20 eV. The experimentally determined fundamental energy transitions originating from the , X, and L points are identified by comparison to theoretical band-to-band transition energies. In order to determine the direct-indirect band gap crossing point, the measured transition energies at the X point have to be aligned by the calculated position of the highest valence state. Thereby density-functional theory (DFT) based approaches to the electronic structure, ranging from the standard (semi)local generalized gradient approximation (GGA), self-energy corrected local density approximation (LDA-1/2), and meta-GGA DFT (TB-mBJLDA) to hybrid functional DFT and many-body perturbation theory in the GW approximation, are applied to random and special quasirandom structure models of zb-Al x Ga 1−x N. This study provides interesting insights into the accuracy of the various numerical approaches and contains reliable ab initio data on the electronic structure and fundamental alloy band gaps of zb-Al x Ga 1−x N. Nonlocal Heyd-Scuseria-Ernzerhof-type hybrid-functional DFT calculations or, alternatively, GW quasiparticle calculations are required to reproduce prominent features of the electronic structure. The direct-indirect band gap crossing point of zb-Al x Ga 1−x N is found in the Al rich composition range at an Al content between x = 0.64 and 0.69 in hybrid functional DFT, which is in good agreement with x = 0.71 determined from the aligned experimental transition energies. Thus our study solves the long-standing debate on the nature of the fundamental zb-Al x Ga 1−x N alloy band gap.
The electronic structure of gallium nitride
Physica B: Condensed Matter, 1993
The results of a density functional calculation on gallium nitride are given. We use norm-conserving pseudopotentials with sufficiently extended sets of plane waves to investigate the ground-state properties and the electronic band structure for the zincblende phase of GaN and compare them with the corresponding results for the wurtzite structure. A comparison with the outcomes of other calculations and with the existing experimental data is also given.
Physical Review B, 2005
We present a combined experimental and theoretical study of the local structure of the GaAs 1−y N y dilute nitride alloy. Experimental results obtained by x-ray absorption spectroscopy have been compared with firstprinciples density-functional supercell calculations and with the predictions of three different valence force field models. Both experiments and calculations find that inclusion of N induces static disorder in the Ga-As bond length distribution. An increase of the Ga-As bond length upon N incorporation in gallium arsenide has been observed; this is due to the competing effects of the decrease of the free lattice parameter and the tensile strain due to pseudomorphic growth. The different theoretical calculations reproduce more or less accurately this bond length expansion; we discuss the performance of the different valence force field models in predicting the measured bond lengths.