Autor: Gorczyca, I. - Prolib Integro

Skocz do pozycji: 1.

Tytuł:: Pressure Dependence of the Light Emission in Zinc-Blende InGaAs/GaAs and InGaN/GaN Quantum Wells
Autorzy:: Łepkowski, S.
Gorczyca, I.
Tematy:: 62.20.D-
62.50.-p
81.40.Jj
78.67.De; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1791301.pdf Link otwiera się w nowym oknie
Opis:: We present theoretical study of the pressure coefficient of the light emission $(dE_{E}/dP)$ in compressively strained zinc-blende InGaAs/GaAs and InGaN/GaN quantum wells, grown in a (001) direction. We investigate the contributions to $dE_{E}$/dP arising from (i) third-order (nonlinear) elasticity, (ii) nonlinear elasticity, originating from pressure dependence of elastic constants, and (iii) nonlinear dependence of elastic constants on composition in InGaAs and InGaN alloys. The obtained results indicate that the use of nonlinear elasticity is essential for determination of $dE_{E}$/dP in the strained InGaAs/GaAs and InGaN/GaN quantum wells, while the inclusion of the nonlinear dependence of elastic constants on composition of InGaAs and InGaN alloys does not improve agreement between the theoretical end experimental values of $dE_{E}$/dP in the considered structures.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Poisson Ratio and Biaxial Relaxation Coefficient in $In_{x}Ga_{1-x}N$ and $In_{x}Al_{1-x}N$ Alloys
Autorzy:: Łepkowski, S.
Gorczyca, I.
Tematy:: 62.20.de
61.43.Dq
81.40.Jj; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1492915.pdf Link otwiera się w nowym oknie
Opis:: We present theoretical results showing dependence of Poisson ratio and biaxial relaxation coefficient on composition and atomic arrangement in wurtzite $In_{x}Ga_{1-x}N$ and $In_{x}Al_{1-x}N$ alloys. Our calculations reveal that the Poisson ratio determined for $In_{x}Ga_{1-x}N$ and $In_{x}Al_{1-x}N$ alloys subjected to a uniaxial stress parallel to the c axis of the wurtzite structure shows significant superlinear dependence on composition. The superlinear bowing in Poisson ratio is enlarged by the effect of In clustering. The biaxial relaxation coefficient determined for $In_{x}Ga_{1-x}N$ and $In_{x}Al_{1-x}N$ alloys subjected to a biaxial stress in the plane perpendicular to the c axis of the wurtzite structure changes superlinearly and linearly with x in $In_{x}Ga_{1-x}N$ and $In_{x}Al_{1-x}N$, respectively. The effect of In atom clustering results in sublinear dependence of the biaxial relaxation coefficient in both $In_{x}Ga_{1-x}N$ and $In_{x}Al_{1-x}N$ alloys.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Influence of Chemistry on the Energy Band Structure: AlAs Versus GaAs
Autorzy:: Bogusławski, P.
Gorczyca, I.
Tematy:: 71.25.Tn
71.10.+x; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1891295.pdf Link otwiera się w nowym oknie
Opis:: Energy band structure of AlAs and GaAs is analyzed in terms of the energy structure of the constituent atoms. Conduction band wave functions are projected on s-, p-, and d-symmetry atomic orbitals. The resulting information is combined with the eigenenergies of Al and Ga atoms, in order to-discuss the character of the band gaps, and the sign of deformation potentials.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: ZnS/ZnSe Superlattices under Pressure
Autorzy:: Gorczyca, I.
Christensen, N. E.
Tematy:: 71.25.Tn
73.20.Dx; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1929746.pdf Link otwiera się w nowym oknie
Opis:: Self-consistent linear muffin-tin orbital method is used to calculate the band structure of ZnS/ZnSe (001) strained-layer superlattice and investigate the influence of hydrostatic pressure on the valence band offset (VBO). Three different strain modes corresponding to various values of the relative thicknesses of both materials are considered. A I → II type conversion associated with the conduction-band crossover between the ZnSe well and ZnS barrier layers is found in agreement with recent experimental data.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: Structural and Elastic Properties of Wurtzite Al-Rich In$\text{}_{x}$Al$\text{}_{1 - x}$N Alloys
Autorzy:: Łepkowski, S. P.
Gorczyca, I.
Tematy:: 62.20.de; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/2048088.pdf Link otwiera się w nowym oknie
Opis:: We present theoretical study of lattice parameters and elastic constants of wurtzite Al-rich In$\text{}_{x}$Al$\text{}_{1 - x}$N (x = 0.125, 0.1875 and 0.25) alloys using self-consistent ab initio calculations with a supercell model. Two different atomic arrangements have been considered for a given x, by either distributing the In atoms as uniformly as possible over the supercell or by clustering the In atoms together in a small part of the supercell. Our calculations reveal that the a and c lattice parameters show almost linear dependence on composition for the alloys with uniform distribution of In atoms, while for the case of alloys with clustered In atoms the c lattice parameter deviates from linearity quite significantly. For the alloys with clustered In atoms, we observe that the values of C$\text{}_{11}$, C$\text{}_{12}$, and C$\text{}_{44}$ elastic constants are significantly smaller than the linear interpolated values between the elastic constants of AlN and InN, and the values of C$\text{}_{33}$ elastic constant are significantly larger than the corresponding interpolated values. For the alloys with uniform distribution of In atoms, only C$\text{}_{11}$ elastic constant deviates significantly from linear dependence on composition.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: Calculations of Native Defects in Cubic AlN
Autorzy:: Gorczyca, I.
Svane, A.
Christensen, N. E.
Tematy:: 73.61.Ey
71.55.Eq; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1950799.pdf Link otwiera się w nowym oknie
Opis:: We have studied the electronic structure of native defects in cubic AlN. N and Al vacancies, antisites and interstitials are investigated in different charge states. We have performed first-principles calculations based on density-functional theory, using two methods. The first one is the Green-function technique based on the linear muffin-tin orbital method in the atomic-spheres approximation. Defects considered are all ideal substantial ones, i.e., no relaxation of the neighboring atoms is allowed for in this method. The results for aluminium vacancy and for nitrogen antisite are compared to the calculations using supercell approach and the full-potential linear muffin-tin orbital (the second method) with lattice relaxation included.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 7.

Tytuł:: Calculations of Native Defects and Impurities in Cubic GaN Including High Pressure Effects
Autorzy:: Gorczyca, I.
Svane, A.
Christensen, Ν. E.
Tematy:: 73.61.Ey
71.55.Eq; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1933745.pdf Link otwiera się w nowym oknie
Opis:: Using the Green-function matrix technique based on the linear muffin-tin orbital method in the atomic-spheres approximation we perform self-consistent calculations of the electronic structure for native defects and impurities in cubic GaN. Native defects as N and Ga vacancies and antisites and substitutional impurities: Zn, C and Ge in different charge states are investigated. Resulting positions of the defect levels are compared with tight-binding and pseudopotential calculations. High pressure behavior is also studied in comparison with some other theoretical and experimental data.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 8.

Tytuł:: Calculations of Point Defects in AlN and GaN; Lattice Relaxation Effects
Autorzy:: Gorczyca, I.
Christensen, N. E.
Svane, A.
Tematy:: 73.61.Ey
71.55.Eq; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1968105.pdf Link otwiera się w nowym oknie
Opis:: Native defects (vacancies, antisites and interstitials) and substitutional impurities (Mg, Zn, and C) in cubic GaN and AlN are studied by means of ab initio theoretical calculations. We examine the energetic positions of the defect levels and lattice relaxations effects. Whereas small relaxations are found in the case of vacancies, the calculations predict that large atomic displacements are associated with antisites. We also discuss the metastable behavior of the nitrogen antisite.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 9.

Tytuł:: Band Structure and Refractive Index of Gallium Nitride Under Pressure
Autorzy:: Perlin, P.
Gorczyca, I.
Suski, T.
Teisseyre, H.
Grzegory, I.
Christensen, N.
Tematy:: 71.25.Tn
78.20.Ci; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1891272.pdf Link otwiera się w nowym oknie
Opis:: The effect of hydrostatic pressure on direct gap and refractive index of GaN is investigated up to 5.5 GPa. Band structure of GaN is calculated by Linear Muffin-Tin Orbitals (LMTO) method for different values of pressure. Resulting pressure coefficient of the main gap and of the refractive index are in a good agreement with the experimental ones.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 10.

Tytuł:: Electronic Structure and Optical Properties of GaAs$\text{}_{1-x}$N$\text{}_{x}$ and Ga$\text{}_{1-x}$B$\text{}_{x}$As Alloys
Autorzy:: Gonzalez Szwacki, N.
Bogusławski, P.
Gorczyca, I.
Christensen, N. E.
Svane, A.
Tematy:: 71.20.Nr
78.20.Bh; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/2035594.pdf Link otwiera się w nowym oknie
Opis:: The electronic band structure of GaAs$\text{}_{1-x}$N$\text{}_{x}$ (x=0.016 and 0.031) and Ga$\text{}_{1-x}$B$\text{}_{x}$As (x= 0.031) is studied by ab initio calculations using a supercell approach. Based on ab initio calculations and group theory we present a comprehensive analysis of the electronic structure of GaAs:N and GaAs:B alloys. In particular, we study the effective mass of conduction electrons in GaAs:N as a function of pressure and the Fermi energy. We find that the lowest conduction band is strongly non-parabolic, which leads to an increase in the effective mass with the electron energy. The rate of the increase is enhanced by the hydrostatic pressure. Theoretical results are compared to experimental data, and a qualitative agreement is found.
Dostawca treści:: Biblioteka Nauki

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