Theoretical investigation of group-IV binary compounds in the P4/ncc phase

Si, Zejian; Chai, Changchun; Zhang, Wei; Song, Yanxing; Yang, Yintang

doi:10.1016/j.rinp.2021.104349

Cited by 7 publications

(5 citation statements)

References 58 publications

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“…The VBM is provided by the SnC layer. The m * h is 0.62m 0 along K-M direction and 0.52m 0 along K-Γ direction, agreeing well with the results of other studies [73]. Our research results demonstrate that the m * e along K-M direction is rather small, which is conducive to the separation of photo-generated electrons and holes.…”

Section: Effective Masses Calculationssupporting

confidence: 91%

Z-scheme SnC/HfS₂ van der Waals heterojunction increases photocatalytic overall water splitting

Dai¹,

Cao²,

Wang³

et al. 2022

J. Phys. D: Appl. Phys.

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Z-scheme heterostructures are efficient photocatalysts due to their small forbidden bandgap and high redox reaction ability. This paper designed the SnC/HfS2 heterojunction and explored its band structure and photocatalytic properties for water decomposition based on density functional theory. Our results suggest that SnC/HfS2 heterostructure is a typical direct Z-scheme heterojunction, which can effectively separate carriers and possesses strong oxidation and reduction capabilities. The VBM of SnC approach to the CBM of HfS2, in favor of the recombination of carriers between layers. The very small interlayer bandgap and appropriate built-in electric field direction make the migration of electrons and holes along the Z-scheme path. The photo-generated electrons on SnC make the hydrogen evolution reaction happen continuously, while the photo-generated holes on HfS2 make the oxygen evolution reaction happen continuously. The calculation of the reaction energy barrier suggests that the procedure of photocatalytic water splitting on the SnC/HfS2 heterostructure can be spontaneous. All the results reveal that SnC/HfS2 heterostructure is a potential direct Z-scheme photocatalyst for the overall water decomposition.

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Section: Effective Masses Calculationssupporting

confidence: 91%

Z-scheme SnC/HfS₂ van der Waals heterojunction increases photocatalytic overall water splitting

Dai¹,

Cao²,

Wang³

et al. 2022

J. Phys. D: Appl. Phys.

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“…However, the most important inconvenience of this system is the low light absorption-emission efficiency of bulk Si-Ge with an indirect band gap that counts against the long-held goal of integrated group IV photonics. This inconvenience can be solved by nanostructuring (quantum confinement) combined with strain [11][12][13] or by exploiting other crystalline structures different from Fd-3m diamond [14,15], such as metastable hexagonal phase [16]. Other solutions are to develop plasmonic structures [17], to fabricate structures with GeSi quantum dots (QDs) embedded in microresonators [18], or by employing hydrogenation technique for passivating detrimental defects [19], all these enabling the enhancement of GeSi and Ge QDs photoluminescence.…”

Section: Introductionmentioning

confidence: 99%

Nanocrystallized Ge-Rich SiGe-HfO2 Highly Photosensitive in Short-Wave Infrared

et al. 2021

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Group IV nanocrystals (NCs), in particular from the Si–Ge system, are of high interest for Si photonics applications. Ge-rich SiGe NCs embedded in nanocrystallized HfO2 were obtained by magnetron sputtering deposition followed by rapid thermal annealing at 600 °C for nanostructuring. The complex characterization of morphology and crystalline structure by X-ray diffraction, μ-Raman spectroscopy, and cross-section transmission electron microscopy evidenced the formation of Ge-rich SiGe NCs (3–7 nm diameter) in a matrix of nanocrystallized HfO2. For avoiding the fast diffusion of Ge, the layer containing SiGe NCs was cladded by very thin top and bottom pure HfO2 layers. Nanocrystallized HfO2 with tetragonal/orthorhombic structure was revealed beside the monoclinic phase in both buffer HfO2 and SiGe NCs–HfO2 layers. In the top part, the film is mainly crystallized in the monoclinic phase. High efficiency of the photocurrent was obtained in a broad spectral range of curves of 600–2000 nm at low temperatures. The high-quality SiGe NC/HfO2 matrix interface together with the strain induced in SiGe NCs by nanocrystallization of both HfO2 matrix and SiGe nanoparticles explain the unexpectedly extended photoelectric sensitivity in short-wave infrared up to about 2000 nm that is more than the sensitivity limit for Ge, in spite of the increase of bandgap by well-known quantum confinement effect in SiGe NCs.

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“…Semiconductor quantum wells (QWs) and superlattices (SLs) have formed the basis of fabricating many modern electronic and optoelectronic devices, including the light-emitting diodes (LEDs), laser diodes (LDs), field-effect transistors (FETs), etc. [1][2][3][4][5][6][7][8][9][10]. Compared with II-VI and III-V compounds, the epitaxial growth of C-based zinc-blende (zb) IV-IV (XC with X = Si, Ge, Sn) binary materials, alloys and heterostructures (i.e., QWs, SLs, etc.)…”

Section: Introductionmentioning

confidence: 99%

“…of higher thermal conductivity, wider electronic energy bandgaps, and higher mechanical strength have recently stimulated interest among the technologists to design different types of device structures (e.g., meta-photonic heterostructures, holographic displays, lasers, etc.) and for the scientists to evaluate their basic traits [1][2][3][4][5][6][7][8][9][10]. The progress in device engineering has Solids 2023, 4 288 demanded careful selection of the C-based wide-bandgap E g (SiC = 2.42 eV; GeC = 1.52 eV) materials which maintain physical properties both at elevated temperatures and higher radiation levels [2][3][4][5][6][7][8][9].…”

Section: Introductionmentioning

confidence: 99%

“…and for the scientists to evaluate their basic traits [1][2][3][4][5][6][7][8][9][10]. The progress in device engineering has Solids 2023, 4 288 demanded careful selection of the C-based wide-bandgap E g (SiC = 2.42 eV; GeC = 1.52 eV) materials which maintain physical properties both at elevated temperatures and higher radiation levels [2][3][4][5][6][7][8][9]. A major precondition for realizing commercial wide-bandgap heterojunction-based devices requires large-area substrates for the preparation of functional multilayer structures.…”

Section: Introductionmentioning

confidence: 99%

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Evaluating Phonon Characteristics by Varying the Layer and Interfacial Thickness in Novel Carbon-Based Strained-Layer Superlattices

Talwar,

Becla

2023

Solids

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Systematic results of lattice dynamical calculations are reported as a function of m and n for the novel (SiC)m/(GeC)n superlattices (SLs) by exploiting a modified linear-chain model and a realistic rigid-ion model (RIM). A bond polarizability method is employed to simulate the Raman intensity profiles (RIPs) for both the ideal and graded (SiC)10-Δ/(Si0.5Ge0.5C)Δ/(GeC)10-Δ/(Si0.5Ge0.5C)Δ SLs. We have adopted a virtual-crystal approximation for describing the interfacial layer thickness, Δ (≡0, 1, 2, and 3 monolayers (MLs)) by selecting equal proportions of SiC and GeC layers. Systematic variation of Δ has initiated considerable upward (downward) shifts of GeC-(SiC)-like Raman peaks in the optical phonon frequency regions. Our simulated results of RIPs in SiC/GeC SLs are agreed reasonably well with the recent analyses of Raman scattering data on graded short-period GaN/AlN SLs. Maximum changes in the calculated optical phonons (up to ±~47 cm−1) with Δ = 3, are proven effective for causing accidental degeneracies and instigating localization of atomic displacements at the transition regions of the SLs. Strong Δ-dependent enhancement of Raman intensity features in SiC/GeC are considered valuable for validating the interfacial constituents in other technologically important heterostructures. By incorporating RIM, we have also studied the phonon dispersions [ωjSLq→] of (SiC)m/(GeC)n SLs along the growth [001] as well as in-plane [100], [110] directions [i.e., perpendicular to the growth]. In the acoustic mode regions, our results of ωjSLq→ have confirmed the formation of mini-gaps at the zone center and zone edges while providing strong evidences of the anti-crossing and phonon confinements. Besides examining the angular dependence of zone-center optical modes, the results of phonon folding, confinement, and anisotropic behavior in (SiC)m/(GeC)n are compared and contrasted very well with the recent first-principles calculations of (GaN)m/(AlN)n strained layer SLs.

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Theoretical investigation of group-IV binary compounds in the P4/ncc phase

Cited by 7 publications

References 58 publications

Z-scheme SnC/HfS₂ van der Waals heterojunction increases photocatalytic overall water splitting

Z-scheme SnC/HfS₂ van der Waals heterojunction increases photocatalytic overall water splitting

Nanocrystallized Ge-Rich SiGe-HfO2 Highly Photosensitive in Short-Wave Infrared

Evaluating Phonon Characteristics by Varying the Layer and Interfacial Thickness in Novel Carbon-Based Strained-Layer Superlattices

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Theoretical investigation of group-IV binary compounds in the P4/ncc phase

Cited by 7 publications

References 58 publications

Z-scheme SnC/HfS2 van der Waals heterojunction increases photocatalytic overall water splitting

Z-scheme SnC/HfS2 van der Waals heterojunction increases photocatalytic overall water splitting

Nanocrystallized Ge-Rich SiGe-HfO2 Highly Photosensitive in Short-Wave Infrared

Evaluating Phonon Characteristics by Varying the Layer and Interfacial Thickness in Novel Carbon-Based Strained-Layer Superlattices

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Product

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Z-scheme SnC/HfS₂ van der Waals heterojunction increases photocatalytic overall water splitting

Z-scheme SnC/HfS₂ van der Waals heterojunction increases photocatalytic overall water splitting