Two novel Ge phases and their Si Ge alloys with excellent electronic and optical properties

Fan, Qingyang; Chai, Changchun; Wei, Qun; Zhou, Peikun; Yang, Yintang

doi:10.1016/j.matdes.2017.07.036

Cited by 29 publications

(26 citation statements)

References 75 publications

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“…The 3D surface constructions of the shear modulus G , Young’s modulus E , and Poisson’s ratio for Si- and Ge-diamondyne are shown in Figure 4. If the material is elastic isotropic, the three-dimensional view of its elastic modulus is a sphere [51,52,53]. For the Young’s moduli in Figure 4a,b, the Si- and Ge-diamondyne both exhibit mechanical anisotropy and the Si-diamondyne shows a larger mechanical anisotropy in Young’s modulus than the Ge-diamondyne.…”

Section: Resultsmentioning

confidence: 99%

Electronic, Mechanical and Elastic Anisotropy Properties of X-Diamondyne (X = Si, Ge)

et al. 2019

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The three-dimensional (3D) diamond-like semiconductor materials Si-diamondyne and Ge-diamondyne (also called SiC4 and GeC4) are studied utilizing density functional theory in this work, where the structural, elastic, electronic and mechanical anisotropy properties along with the minimum thermal conductivity are considered. SiC4 and GeC4 are semiconductor materials with direct band gaps and wide band gaps of 5.02 and 5.60 eV, respectively. The Debye temperatures of diamondyne, Si- and Ge-diamondyne are 422, 385 and 242 K, respectively, utilizing the empirical formula of the elastic modulus. Among these, Si-diamondyne has the largest mechanical anisotropy in the shear modulus and Young’s modulus, and Diamond has the smallest mechanical anisotropy in the Young’s modulus and shear modulus. The mechanical anisotropy in the Young’s modulus and shear modulus of Si-diamondyne is more than three times that of diamond as determined by the characterization of the ratio of the maximum value to the minimum value. The minimum thermal conductivity values of Si- and Ge-diamondyne are 0.727 and 0.524 W cm−1 K−1, respectively, and thus, Si- and Ge-diamondyne may be used in the thermoelectric industry.

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Section: Resultsmentioning

confidence: 99%

Electronic, Mechanical and Elastic Anisotropy Properties of X-Diamondyne (X = Si, Ge)

et al. 2019

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“…This is due to the existence of many differently sized rings of silicon atoms in the t ‐Si 64 , such as five‐membered rings, six‐membered rings, eight‐membered rings, ten‐membered rings and twelve‐membered rings. The rings containing different numbers of atoms will increase the energy of the system to varying degrees ,. The planar rings and five‐membered rings will both result in more severe distortion ,.…”

Section: Resultsmentioning

confidence: 99%

“…In addition, in order to obtain direct band gap semiconductor materials, Si−Ge alloys are the most commonly used method. Germanium atoms successfully transformed some indirect band gap silicon into direct band gap semiconductors . Si−Ge alloys can also reduce thermal conductivity and become candidates for thermoelectric materials with higher thermoelectric figures of merit, ZT .…”

Section: Introductionmentioning

confidence: 99%

t‐Si₆₄: A Novel Silicon Allotrope

et al. 2018

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Utilizing first principle calculations, a novel Si64 silicon allotrope in the I41/amd space group with tetragonal symmetry (denoted as t‐Si64 below) is proposed in this work. In addition, also its structural, anisotropic mechanical, and electronic properties along with its minimum thermal conductivity κmin were predicted. The mechanical and thermodynamic stability of t‐Si64 were evaluated by means of elastic constants and phonon spectra. The electronic band structure indicates that t‐Si64 is an indirect band gap semiconductor with a band gap: 0.67 eV (primitive cell) compared to a direct band gap of 0.70 eV with respect to a conventional cell. The minimum thermal conductivity of t‐Si64 (0.74 W cm−1 K−1) is much smaller than that of diamond silicon (1.13 W cm−1 K−1). Therefore, Si−Ge alloys in the I41/amd space group are potential thermoelectric materials.

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“…Therefore, from the three-dimensional contour plots in Figure 4, it can be clearly seen that the mechanical anisotropy of the E of AlN is the largest. Similar to other materials [47][48][49][50], the Y max /Y min ratio (where Y is E, G and v) is used to quantify the anisotropy of various elastic moduli in this work. The maximum values and the minimum values of the E for XN in the Pm−3n phase are illustrated in Figure 5a, respectively.…”

Section: Mechanical and Anisotropy Propertiesmentioning

confidence: 99%

Physical Properties of XN (X = B, Al, Ga, In) in the Pm−3n phase: First-Principles Calculations

et al. 2020

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Three direct semiconductor materials and one indirect semiconductor material, Pm−3n XN (X = B, Al, Ga, In), are investigated in our work, employing density functional theory (DFT), where the structural properties, stability, elastic properties, elastic anisotropy properties and electronic properties are included. The shear modulus G and bulk modulus B of Pm−3n BN are 290 GPa and 244 GPa, respectively, which are slightly less than the values of B and G for c-BN and Pnma BN, while they are larger than those of C64 in the I41/amd phase. The shear modulus of Pm−3n BN is the greatest, and the shear modulus of C64 in the I41/amd phase is the smallest. The Debye temperatures of BN, AlN, GaN and InN are 1571, 793, 515 and 242 K, respectively, using the elastic modulus formula. AlN has the largest anisotropy in the Young’s modulus, shear modulus, and Poisson‘s ratio; BN has the smallest elastic anisotropy in G; and InN has the smallest elastic anisotropy in the Poisson’s ratio. Pm−3n BN, AlN, GaN and InN have the smallest elastic anisotropy along the (111) direction, and the elastic anisotropy of the E in the (100) (010) (001) planes and in the (011) (101) (110) planes is the same. The shear modulus and Poisson’s ratio of BN, AlN, GaN and InN in the Pm−3n phase in the (001), (010), (100), (111), (101), (110), and (011) planes are the same. In addition, AlN, GaN and InN all have direct band-gaps and can be used as a semiconductor within the HSE06 hybrid functional.

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Two novel Ge phases and their Si Ge alloys with excellent electronic and optical properties

Cited by 29 publications

References 75 publications

Electronic, Mechanical and Elastic Anisotropy Properties of X-Diamondyne (X = Si, Ge)

Electronic, Mechanical and Elastic Anisotropy Properties of X-Diamondyne (X = Si, Ge)

t‐Si₆₄: A Novel Silicon Allotrope

Physical Properties of XN (X = B, Al, Ga, In) in the Pm−3n phase: First-Principles Calculations

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Two novel Ge phases and their Si Ge alloys with excellent electronic and optical properties

Cited by 29 publications

References 75 publications

Electronic, Mechanical and Elastic Anisotropy Properties of X-Diamondyne (X = Si, Ge)

Electronic, Mechanical and Elastic Anisotropy Properties of X-Diamondyne (X = Si, Ge)

t‐Si64: A Novel Silicon Allotrope

Physical Properties of XN (X = B, Al, Ga, In) in the Pm−3n phase: First-Principles Calculations

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Product

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t‐Si₆₄: A Novel Silicon Allotrope