Thermal expansion and lattice parameters of group IV semiconductors

Reeber, Robert R.; Wang, Kai

doi:10.1016/s0254-0584(96)01808-1

Cited by 145 publications

(55 citation statements)

References 23 publications

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“…However, the quasiparticle energies themselves are temperature-dependent because of additional finite-temperature effects, such as lattice expansion and electron-phonon renormalization [10,[20][21][22][23][24]. We found that the thermal-expansion correction to the indirect band gap is small and amounts only to a 2.5 meV increase of the LDA band gap as the lattice constant increases from the 0 K to the 400 K value [25], in agreement with Ref. 22.…”

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confidence: 89%

Phonon-Assisted Optical Absorption in Silicon from First Principles

et al. 2012

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The phonon-assisted interband optical absorption spectrum of silicon is calculated at the quasiparticle level entirely from first principles. We make use of the Wannier interpolation formalism to determine the quasiparticle energies, as well as the optical transition and electron-phonon coupling matrix elements, on fine grids in the Brillouin zone. The calculated spectrum near the onset of indirect absorption is in very good agreement with experimental measurements for a range of temperatures. Moreover, our method can accurately determine the optical absorption spectrum of silicon in the visible range, an important process for optoelectronic and photovoltaic applications that cannot be addressed with simple models. The computational formalism is quite general and can be used to understand the phonon-assisted absorption processes in general.The phonon-assisted absorption of light in materials is an important optical process both from a fundamental and from a technological point of view. Intraband light absorption by free carriers in metals and doped semiconductors requires the additional momentum provided by the lattice vibrations or defects, while phonon-assisted processes determine the onset of absorption in indirectband-gap semiconductors (Fig. 1). Moreover, the value of the direct band gap in silicon (3.4 eV [1]) is large and precludes optical absorption in the visible. However, silicon is a commercially successful photovoltaic material because of the indirect optical transitions that enable photon capture in the spectral region between the indirect (1.1 eV [2]) and direct band gaps.Despite their importance, at present, only a very limited number of first-principles studies of phonon-assisted optical absorption spectra exist. Ab initio calculations of direct optical absorption spectra including excitonic effects have already been performed for Si and other bulk semiconductors [3] and the underlying methodology is presently well established [4,5]. Phonon-assisted absorption studies are more involved, however, and the associated computational cost is much higher than the direct case. The calculation of the indirect absorption coefficient involves a double sum over k-points in the first Brillouin zone (BZ) to account for all initial and final electron states. In addition, these sums must be performed with a very fine sampling of the zone to get an adequate spectral resolution. The computational cost associated with these BZ sums is in fact prohibitive with the usual methods. Phonon-assisted absorption calculations have been done for the special case of free-carrier absorption in semiconductors [6], where the carriers are initially limited to a region near the Γ point of the first BZ, but a full calculation using brute-force methods for the general case remains beyond the reach of modern computers.The difficulty of zone-integral convergence can be addressed with the maximally-localized Wannier function interpolation method [7]. Using this technique, the quasiparticle energies [8] and optical transition matrix ele...

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confidence: 89%

Phonon-Assisted Optical Absorption in Silicon from First Principles

et al. 2012

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“…As temperature increases from 20 to 60 K, the Si CTE first decreases and then increases with a minimum around 70 K, 45 while the Ge CTE monotonically increases ( Fig. 9(b)).…”

Section: Discussionmentioning

confidence: 99%

Structural and optical properties of axial silicon-germanium nanowire heterojunctions

Wang

Tsybeskov

Kamins

et al. 2015

Journal of Applied Physics

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Access and use of this website and the material on it are subject to the Terms and Conditions set forth at NRC Publications Record / Notice d'Archives des publications de CNRC:http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/ctrl?lang=en http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/ctrl?lang=fr READ THESE TERMS AND CONDITIONS CAREFULLY BEFORE USING THIS WEBSITE.http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/jsp/nparc_cp.jsp?lang=en Vous avez des questions? Nous pouvons vous aider. Pour communiquer directement avec un auteur, consultez la première page de la revue dans laquelle son article a été publié afin de trouver ses coordonnées. Si vous n'arrivez pas à les repérer, communiquez avec nous à PublicationsArchive-ArchivesPublications@nrc-cnrc.gc.ca.

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“…The latter data were taken from Refs. [14] and [15], respectively. For the stiffness constants of GaN and Si the values published in Refs.…”

Section: Resultsmentioning

confidence: 99%

Characterization of growth defects in thin GaN layers with X‐ray microbeam

Barabash

Ice

Röder

et al. 2007

Physica Status Solidi (b)

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The spatially resolved distribution of strain, misfit and threading dislocations, and crystallographic orientation in uncoalesced GaN layers grown on Si(111) by maskless cantilever epitaxy or by pendeo epitaxy on SiC was studied by white beam Laue X-ray microdiffraction, scanning electron and orientation imaging microscopy. Tilt boundaries formed at the column/wing interface depending on the growth conditions. A depth dependent deviatoric strain gradient is found in the GaN. The density of misfit dislocations as well as their arrangement within different dislocation arrays was quantified. Two different kinds of tilt (parallel and perpendicular to the stripe direction) manifested themselves by mutually orthogonal displacements of the (0006) GaN Laue spot relative to the Si(444) Laue spot. The origin of the tilts is discussed with respect to the miscut of the Si(111) surface and misfit dislocations formed at the interface. Regular oscillations of the conventional wing tilt were observed. Irregular crystallographic tilts fluctuations were found in the direction parallel to stripes. The amplitude of fluctuations is an order of magnitude smaller for layers with a lower defects density.

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Thermal expansion and lattice parameters of group IV semiconductors

Cited by 145 publications

References 23 publications

Phonon-Assisted Optical Absorption in Silicon from First Principles

Phonon-Assisted Optical Absorption in Silicon from First Principles

Structural and optical properties of axial silicon-germanium nanowire heterojunctions

Characterization of growth defects in thin GaN layers with X‐ray microbeam

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