Raman Spectroscopy and Electroreflectance Studies of Self-Assembled SiGe Nanoislands Grown at Various Temperatures

Valakh, M. Ya.; Holiney, R.Yu.; Dzhagan, Veronika; Krasilnik, Z. F.; Lytvyn, O. S.; Lobanov, D. N.; Milekhin, A. G.; Nikiforov, A. I.; Новиков, А. В.; Pchelyakov, O. P.; Yukhymchuk, Volodymyr

doi:10.1134/1.1853444

Cited by 20 publications

(7 citation statements)

References 12 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In summary, and as has been shown in a number of studies [106,107,109,112,115,118], [123, 125-127, 130-133, 135], the Si-Ge and Ge-Ge mode frequencies as a function of x in the dome superlattice show a decrease with respect to those in the comparable fully strained planar superlattice, which means that the average strain in the dome superlattice is reduced from that in the planar superlattice. The strain reduction can be appreciable [126,131,132]. However, the situation is reversed for the island Si-Si mode, which contradicts the case of the Si-Ge and Ge-Ge modes.…”

Section: Vibrational Properties Of Ge Dots and Si 1−x Ge X Island Sup...mentioning

confidence: 90%

Ge dots and nanostructures grown epitaxially on Si

Baribeau

Rowell

et al. 2006

J. Phys.: Condens. Matter

125

113

View full text Add to dashboard Cite

We review recent progress in the growth and characterization of Si 1−x Ge x islands and Ge dots on (001) Si. We discuss the evolution of the island morphology with Si 1−x Ge x coverage, and the effect of growth parameters or post-growth annealing on the shape of islands and dots. We outline some of the structural, vibrational, and optical properties of Si 1−x Ge x islands and review recent advances in the determination of their composition and strain distribution. In particular, we present an analytical electron transmission microscopy study of the Ge spatial distribution in Ge dots and Si/Si 1−x Ge x island superlattices grown by molecular beam epitaxy and ultra-high vacuum chemical vapour deposition. We describe the use of undulated Si 1−x Ge x island superlattices for infrared detection at telecommunication wavelengths. Finally, we discuss various approaches currently being investigated to engineer Si 1−x Ge x quantum dots and, in particular, control their size, density, and spatial distribution. As examples, we show how C pre-deposition on Si(001) can influence nucleation and growth of Ge islands and how low temperature Si homo-epitaxy can lead to a particular surface cusp morphology that may promote dot nucleation.

show abstract

Section: Vibrational Properties Of Ge Dots and Si 1−x Ge X Island Sup...mentioning

confidence: 90%

Ge dots and nanostructures grown epitaxially on Si

Baribeau

Rowell

et al. 2006

J. Phys.: Condens. Matter

125

113

View full text Add to dashboard Cite

show abstract

“…The vibrational spectrum of the solid solution (alloy) is more complex than the classical two-mode behavior, because they show additional peaks in the intermediate wavenumber region, 205-280 cm −1 . The latter vibrations were suggested as an additional tool to assess the degree of intermixing in the case of heterostructures CZTS/CZTSe, as previously used for studying alloying in binary [27] and elemental [31] heterosystems. Furthermore, the FWHMs of the Raman peaks of the solid solution are close to the width observed in the pure compounds indicating that no significant chemical disorder effects take place in the alloy.…”

Section: Influence Of Composition and Non-stoichiometrymentioning

confidence: 99%

“…In addition to providing the vibrational/phonon spectra of the material, Raman spectroscopy is an efficient and convenient (fast and non-destructive) tool of probing the structure of semiconductors, both bulk, micro-, and nanostructures [27,28], EPC [29], and electronic resonances [30,31]. The knowledge of EPC is particularly important for photovoltaic [32], thermoelectric, and luminescent properties [19,20,23,33].…”

Section: Introductionmentioning

confidence: 99%

Phonon Raman spectroscopy of nanocrystalline multinary chalcogenides as a probe of complex lattice structures

Dzhagan¹,

Litvinchuk²,

Valakh³

et al. 2022

J. Phys.: Condens. Matter

View full text Add to dashboard Cite

Ternary (I-III-VI) and quaternary (I-II-IV-VI) metal-chalcogenides like CuInS2 or Cu2ZnSn(S,Se)4 are among the materials currently most intensively investigated for various applications in the area of alternative energy conversion and light-emitting devices. They promise more sustainable and affordable solutions to numerous applications, compared to more developed and well understood II-VI and III-V semiconductors. Potentially superior properties are based on an unprecedented tolerance of these compounds to non-stoichiometric compositions and polymorphism. However, if not properly controlled, these merits lead to undesirable coexistence of different compounds in a single polycrystalline lattice and huge concentrations of point defects, becoming an immense hurdle on the way toward real-life applications. Raman spectroscopy of phonons has become one of the most powerful tools of structural diagnostics and probing physical properties of bulk and microcrystalline I-III-VI and I-II-IV-VI compounds. The recent explosive growth of the number of reports on fabrication and characterisation of nanostructures of these compounds must be pointed out as well as the steady use of Raman spectroscopy for their characterisation. Interpretation of the vibrational spectra of these compound nanocrystals (NCs) and conclusions about their structure can be complicated compared to bulk counterparts because of size and surface effects as well as emergence of new structural polymorphs that are not realizable in the bulk. This review attempts to summarise the present knowledge in the field of I-III-VI and I-II-IV-VI NCs regarding their phonon spectra and capabilities of Raman and IR spectroscopies in the structural characterisations of these promising families of compounds.

show abstract

“…Here, we studied the dependence of the interface alloying and strain evolution of 3 nm spherical core NCs embedded in the CdS shell with two different shapes: spherical or plate-like. Apart from the novelty and the interesting optical properties of the dot-in-plates structures, one motivation to compare core/shell materials with shells of different shape is to evaluate the influence of strain inhomogeneity on the interdiffusion at the interface of two lattice mismatched semiconductors. , In this study, we succeeded to identify both the CdSe- and CdS-like alloyed interface-related vibrations and to relate the higher-order Raman features at 480–490 cm –1 as well as in the range of 700–1100 cm –1 with certain combinations of first-order optical modes of the core, the shell, and the alloyed interface. We also propose a method based on the frequency of the alloyed phonon modes to extract the average composition of the alloy interface.…”

Section: Introductionmentioning

confidence: 99%

“…Apart from the novelty and the interesting optical properties of the dot-in-plates structures, 18 one motivation to compare core/ shell materials with shells of different shape is to evaluate the influence of strain inhomogeneity on the interdiffusion at the interface of two lattice mismatched semiconductors. 19,20 In this study, we succeeded to identify both the CdSe-and CdS-like alloyed interface-related vibrations and to relate the higherorder Raman features at 480−490 cm −1 as well as in the range of 700−1100 cm −1 with certain combinations of first-order optical modes of the core, the shell, and the alloyed interface.…”

Section: ■ Introductionmentioning

confidence: 99%

Raman- and IR-Active Phonons in CdSe/CdS Core/Shell Nanocrystals in the Presence of Interface Alloying and Strain

et al. 2013

View full text Add to dashboard Cite

Semiconductor core–shell nanocrystals (NCs) have greatly improved luminescent properties including better resistance to photobleaching and ligand exchange. It was suggested that compound alloying at the core/shell interface could play an important role in obtaining bright and stable NCs. Here, we investigate the interface composition and strain evolution in spherical and dot-in-plate CdSe/CdS nanocrystals with shell thickness ranging from 1 to 3 nm, using a combination of Raman and infrared spectroscopy. A slower rate of strain accumulation in the core is observed for dot-in-plate nanocrystals and is linked to the anisotropic shape of the plate-like shell. We resolved the respective contributions of the core, shell, and alloyed interface and observed a drastic change of the shell-related Raman feature with the appearance of the bulk-like optical phonon in the shell thicker than 1 nm. The average composition of the alloy interface is estimated using the frequencies of the alloy modes. Because of the high crystallinity of the samples, up to fourth-order optical phonon processes are observed and analyzed. This work confirms the presence of an alloyed interface in core/shell CdSe/CdS structures of different geometries and establishes a precise roadmap for its quantitative analysis using vibrational spectroscopy.

show abstract

Raman Spectroscopy and Electroreflectance Studies of Self-Assembled SiGe Nanoislands Grown at Various Temperatures

Cited by 20 publications

References 12 publications

Ge dots and nanostructures grown epitaxially on Si

Ge dots and nanostructures grown epitaxially on Si

Phonon Raman spectroscopy of nanocrystalline multinary chalcogenides as a probe of complex lattice structures

Raman- and IR-Active Phonons in CdSe/CdS Core/Shell Nanocrystals in the Presence of Interface Alloying and Strain

Contact Info

Product

Resources

About