Phonons in Ordered Semiconductor Alloys

Mascarenhas, A.; Cheong, Hyeonsik; Seong, Maeng-Je; Alsina, F.

doi:10.1007/978-1-4615-0631-7_14

Cited by 19 publications

(32 citation statements)

References 34 publications

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“…It turns out that the binding energy for the non-twisted interface (24.0 meV Å −2 ) is larger than that of the twisted one (21 meV Å −2 ), which indicates that the non-twisted interface structure is the energetically favorable equilibrium phase and the twisted one is a metastable phase formed in the non-equilibrium growth process. As a matter of fact, a metastable phase is often observed in the non-equilibrium epitaxial growth by MBE and MOCVD; for instance, a well-known phenomenon, spontaneous ordering, has been observed in the epitaxial growth of a semiconductor alloy, GaInP on GaAs in particular [32]. The twisted interface structure is observed by our HR-TEM measurement in a PbTe/CdTe SHJ grown by MBE, as shown in figure 3.…”

Section: The Growth Simulation Of Cdte/pbte(111) Heterojunctionssupporting

confidence: 51%

Twisted ZB–CdTe/RS–PbTe (111) heterojunction as a metastable interface structure

et al. 2012

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The heterostructures of (zinc-blende)-CdTe/(rock-salt)-PbTe are typically found to have their common cubic axes aligned to each other, as in the case of PbTe quantum dots embedded in a CdTe matrix. In this work, we perform both theoretical and experimental studies on the CdTe/PbTe heterostructure in a different geometry: a planar CdTe/PbTe (111) heterostructure. We simulate the epitaxial growth of CdTe (PbTe) on the (111) PbTe (CdTe) substrate, using a density-functional theory. A twisted CdTe/PbTe (111) interface structure has been predicted in the layer-by-layer epitaxial growth on the (111) substrate, in contrast to the non-twisted CdTe/PbTe (111) interface reported in the literature. This predicted structure has been confirmed experimentally in the heterostructure grown by molecular beam epitaxy, using a high-resolution transmission electron microscope. The twisted interface has a lower binding energy than the nontwisted one, indicating that the twisted structure is a metastable phase formed in 5

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Section: The Growth Simulation Of Cdte/pbte(111) Heterojunctionssupporting

confidence: 51%

Twisted ZB–CdTe/RS–PbTe (111) heterojunction as a metastable interface structure

et al. 2012

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“…Representative systems are In 1−x Ga x As, ZnTe 1−x Se x and In 1−x Ga x P, respectively. 7 The related MREI-VCA TO schemes are schematically represented in Fig. 2, while approximating the MREI branches to straight lines, for simplicity.…”

Section: Introductionmentioning

confidence: 99%

Unification of the phonon mode behavior in semiconductor alloys: Theory andab initiocalculations

Pagès¹,

Postnikov²,

Kassem³

et al. 2008

Phys. Rev. B

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We demonstrate how to overcome serious problems in understanding and classification of vibration spectra in semiconductor alloys, following from traditional use of the virtual crystal approximation (VCA). We show that such different systems as InGaAs (1-bond→1-mode behavior), InGaP (modified 2-mode) and ZnTeSe (2-bond→1-mode) obey in fact the same phonon mode behavior -hence probably a universal one -of a percolation-type (1-bond→2-mode). The change of paradigm from the 'VCA insight' (an averaged microscopic one) to the 'percolation insight' (a mesoscopic one) offers a promising link towards the understanding of alloy disorder. The discussion is supported by ab initio simulation of the phonon density of states at the zone-center of representative supercells at intermediary composition (ZnTeSe) and at the impurity-dilute limits (all systems). In particular, we propose a simple ab initio 'protocol' to estimate the basic input parameters of our semi-empirical 'percolation' model for the calculation of the 1-bond→2-mode vibration spectra of zincblende alloys. With this, the model turns self-sufficient.

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“…Recently, the effect was observed in InAs/GaSb by some of us, and speculated as due to the transverse mode of the phonon-polariton [22]. The same effect was also observed in yet another system, a spontaneously ordered GaInP alloy -a monolayer superlattice along the [1 � 11] direction [27]. There two possible mechanisms were given: the q-dependent Frohlich interaction and the Frohlich interaction due to the electrical field induced by surface charges, in connection with the similar effect reported for a bulk material (GaAs) with doping [28].…”

mentioning

confidence: 52%

“…However, we cannot simply attribute the difference to the composition dependence, because one set of samples were grown by MBE, while the other by MOCVD. It is well known that different types of composition modulations may occur in III-V alloys, and the specific form of the modulation depends sensitively on the growth method and condition [34]. Therefore, more systematic investigation is required to understand the microscopic structures of the alloys.…”

Section: Inas1-xsbx Alloysmentioning

confidence: 99%

Raman Scattering Study of Lattice Vibrations in the Type-II Superlattice InAs/InAs1−xSbx

et al. 2017

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InAs/InAs1-xSbx superlattice system differ distinctly from two well-studied superlattice systems GaAs/AlAs and InAs/GaSb, in terms of electronic band alignment, common-element at the interface, and phonon spectrum overlapping of the constituents. This fact leads to unique electronic and vibrational properties of the InAs/InAs1-xSbx system when compared to the other two systems. In this work, we report a polarized Raman study on the vibrational properties of the InAs/InAs1-xSbx SLs as well as selected InAs1-xSbx alloys, all grown on GaSb substrates by either MBE or MOCVD, from both growth surface and cleaved edge. In the SL, from the (001) backscattering geometry, an InAs-like LO mode is observed as the primary feature and its intensity is found to increase with increasing Sb composition; from the (110) cleaved edge backscattering geometry, an InAs-like TO mode is observed as the main feature in two crosspolarization configurations, but an additional InAs-like "forbidden" LO mode was observed in two parallel-polarization configurations. InAs1-xSbx alloys lattice-matched to the substrate (xSb ~ 0.09) grown by MBE were also found to exhibit the "forbidden" LO mode, implying the existence of some unexpected [001] modulation, but the strained xSb ~ 0.35 samples grown by MOCVD were found to behavior like a disordered alloy. The primary conclusions are (1) the InAs-like LO or TO mode could be either a confined or quasi-confined mode in the InAs layers of the SL or extended mode of the whole structure, depending on the Sb composition; (2)InAs/InAsSb and InAs/GaSb SLs exhibit significantly different behaviors in the cleaved edge geometry, but qualitatively similar in the (001) geometry; and (3) the appearance of the "forbidden" LO-like mode is a universal signature for SLs and bulk systems resulting from mixing of phonon modes due to structural modulation or symmetry reduction.3

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Phonons in Ordered Semiconductor Alloys

Cited by 19 publications

References 34 publications

Twisted ZB–CdTe/RS–PbTe (111) heterojunction as a metastable interface structure

Twisted ZB–CdTe/RS–PbTe (111) heterojunction as a metastable interface structure

Unification of the phonon mode behavior in semiconductor alloys: Theory andab initiocalculations

Raman Scattering Study of Lattice Vibrations in the Type-II Superlattice InAs/InAs1−xSbx

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