Ab initio calculation of vibrational spectra of orthorhombic IV–VI layered crystals

Gashimzade, F. M.; Guseinova, D. A.; Jahangirli, Z. A.; Nizametdinova, M. A.

doi:10.1134/s1063783413090126

Cited by 9 publications

(11 citation statements)

References 27 publications

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“…Growth at a low GeS precursor temperature (400 °C) favors lateral attachment of crystalline GeS while producing ultrathin GeS top layers. Raman linescans detect only SnS modes in the center (Figure b,c) while the periphery shows the A g and B 3g vibrational modes of GeS (Figure d), − consistent with the TEM results (Figure ; Figures S4 and S5). Note the significant redshift of the GeS modes near the interface (Figure b), most evident for the B 3g rocksalt-type mode along a which shifts from 210 cm –1 near the periphery (consistent with unstrained GeS) to 205 cm –1 at the lateral interface to SnS.…”

Section: Resultssupporting

confidence: 85%

Lateral Heterostructures of Multilayer GeS and SnS van der Waals Crystals

2020

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Engineered heterostructures derive distinct properties from materials integration and interface formation. Twodimensional crystals have been combined to form vertical stacks and lateral heterostuctures with covalent line interfaces. While thicker vertical stacks have been realized, lateral heterostructures from multilayer van der Waals crystals, which could bring the benefits of high-quality interfaces to bulk-like layered materials, have remained much less explored. Here, we demonstrate the integration of anisotropic layered Sn and Ge monosulfides into complex heterostructures with seamless lateral interfaces and tunable vertical design using a two-step growth process. The anisotropic lattice mismatch at the lateral interfaces between GeS and SnS is relaxed via dislocations and interfacial alloying. Nanoscale optoelectronic measurements by cathodoluminescence spectroscopy show the characteristic light emission of joined high-quality van der Waals crystals. Spectroscopy across the lateral interface indicates valley-selective luminescence in the bulk SnS component that arises due to anisotropic electron transfer across the interface. The results demonstrate the ability to realize high-quality lateral heterostructures of multilayer van der Waals crystals for diverse applications, e.g., in optoelectronics or valleytronics.

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Section: Resultssupporting

confidence: 85%

Lateral Heterostructures of Multilayer GeS and SnS van der Waals Crystals

2020

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“…[ 11 ] Subsequent GeS growth leads to a significant increase in the lateral flake size while maintaining faceted shapes (Figure 1c ; Figure S1 , Supporting Information), consistent with GeS attachment to the lateral edges of the SnS seeds. Optical images confirm this scenario, showing contrast between the centers and the edge rim (Figure 1d ) while Raman line scans (Figure 1e ) detect SnS [ 13 ] and GeS [ 14 , 15 , 16 ] vibrational modes in the center and edge regions, respectively (Figure 1f,g ).…”

Section: Resultsmentioning

confidence: 65%

Multilayer Lateral Heterostructures of Van Der Waals Crystals with Sharp, Carrier–Transparent Interfaces

et al. 2021

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Research on engineered materials that integrate different 2D crystals has largely focused on two prototypical heterostructures: Vertical van der Waals stacks and lateral heterostructures of covalently stitched monolayers. Extending lateral integration to few layer or even multilayer van der Waals crystals could enable architectures that combine the superior light absorption and photonic properties of thicker crystals with close proximity to interfaces and efficient carrier separation within the layers, potentially benefiting applications such as photovoltaics. Here, the realization of multilayer heterstructures of the van der Waals semiconductors SnS and GeS with lateral interfaces spanning up to several hundred individual layers is demonstrated. Structural and chemical imaging identifies {110} interfaces that are perpendicular to the (001) layer plane and are laterally localized and sharp on a 10 nm scale across the entire thickness. Cathodoluminescence spectroscopy provides evidence for a facile transfer of electron‐hole pairs across the lateral interfaces, indicating covalent stitching with high electronic quality and a low density of recombination centers.

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“…The similar phenomenon has been observed in laser thinned GeSe nanosheets, which was attributed to the small thickness and the defects of the sample. 27, 3 , 2 2 and 1 vibration modes of the Ge-Se bonds, [35][36][37] respectively. The other group includes the other five peaks at 52 cm -1 , 84 cm -1 , 109 cm -1 , 239 cm -1 and 256 cm -1 , which were assigned to Se-related defects: the first three peaks correspond to the vibration modes of selenium octacyclic (Se8) molecule, 38 and the last two peaks correspond to the polymer-like structure.…”

Section: Methodsmentioning

confidence: 99%

Synthesis and photoluminescence of high density GeSe triangular nanoplate arrays on Si substrates

Li¹,

Zhang²,

Lv³

et al. 2020

Nanotechnology

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We have grown germanium selenide (GeSe) triangular nanoplate arrays (TNAs) with a high density (3.82 × 10 6 / mm 2 ) on the Si (111) substrate using a simple thermal evaporation method. The thickness and trilateral lengths of a single triangular nanoplate were statistically estimated by atomic force microscopy (AFM) as 44 nm, 365 nm, 458 nm and 605 nm, respectively. Transmission electron microscopy (TEM) images and Xray diffraction (XRD) patterns show that the TNAs were composed of single crystalline GeSe phase. The Se-related defects in the lattice were also revealed by TEM images and Raman vibration modes. Unlike previously reported GeSe compounds, the GeSe TNAs exhibited temperature-dependent photoluminescence (PL). In addition, not previously reported PL peak (1.25 eV) of the 44 nm thick TNAs at 5 K was in the gaps between those of GeSe monolayers (1.5 nm) and thin films (400 nm), revealing a close relationship between the PL peak and the thickness of GeSe. The high-density structure and temperature-dependent PL of the TNAs on the Si substrate may be useful for temperature controllable semiconductor nanodevices.

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Ab initio calculation of vibrational spectra of orthorhombic IV–VI layered crystals

Cited by 9 publications

References 27 publications

Lateral Heterostructures of Multilayer GeS and SnS van der Waals Crystals

Lateral Heterostructures of Multilayer GeS and SnS van der Waals Crystals

Multilayer Lateral Heterostructures of Van Der Waals Crystals with Sharp, Carrier–Transparent Interfaces

Synthesis and photoluminescence of high density GeSe triangular nanoplate arrays on Si substrates

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