Thermoelectric power factor enhancement of calcium-intercalated layered silicene by introducing metastable phase

Terada, T.; Ishibe, Takafumi; Katayama, Toranosuke; Satō, Kazunori; Nakano, Hideyuki; Nakamura, Yoshiaki

doi:10.35848/1882-0786/ac2a57

Cited by 10 publications

(7 citation statements)

References 43 publications

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“…Then the lattice misfit at the interface of the CaSi 2 film and Si(111) substrate is discussed. The orientation relationship between the Si(111) substrate and the epitaxial CaSi 2 film (or grains) in the present work was (001) CaSi2 //(111) Si , [1][2][3][4][5][6][7][8][9][10] CaSi2 // Si , and [001] CaSi2 //[111] Si . Thus, the lattice misfit is calculated from the lattice parameter, a, for each CaSi 2 phase and the d 110 lattice spacing of the Si substrate.…”

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confidence: 66%

Growth of metastable 2H-CaSi₂ films on Si(111) substrates with ultrathin SiO₂ films by solid phase epitaxy

Oh-ishi,

Kojima,

Yoshizaki

et al. 2023

Appl. Phys. Express

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The Si-nano dot substrates formed using the ultrathin silicon oxide films were applied to fabricate CaSi2 films. The CaSi2 formed by this process was identified as the metastable phase 2H as the main component, and the 1H structure existed partially at the grains of the 2H phase. Although no experimental reports exist for the formation of 2H-CaSi2 crystal, the Si-nano dot substrates are considered as the high-entropy substrate to form the metastable phases. We experimentally determined the lattice parameter of the 2H phase by the annular dark field–scanning transmission electron microscopy observations using the Si as an internal standard sample.

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confidence: 66%

Growth of metastable 2H-CaSi₂ films on Si(111) substrates with ultrathin SiO₂ films by solid phase epitaxy

Oh-ishi,

Kojima,

Yoshizaki

et al. 2023

Appl. Phys. Express

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“…To solve this problem, we focus on Ca intercalated layered silicene, CaSi 2 that is stable in the air. 54) In our previous works, 55,56) it was revealed that CaSi 2 including metastable high-buckled silicene was formed with the composition ratio deviation from stoichiometry by solid phase epitaxy (SPE), leading to experimental achievement of high power factor at RT. The relation between composition ratio deviation and deformation of buckled structure is unclear.…”

Section: Introductionmentioning

confidence: 99%

The effect of interdiffusion during formation of epitaxial Ca intercalated layered silicene film on its thermoelectric power factor

Terada

Ishibe

Kobayashi³

et al. 2022

Jpn. J. Appl. Phys.

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Deformation of silicene buckled structure attracts great interest for the possibility of ultrahigh thermoelectric power factor. Therefore, the control method of silicene buckled structure is needed. Here, we developed the method to control composition ratio in epitaxial Ca intercalated layered silicene (CaSi2) film formed by solid phase epitaxy through an atomic interdiffusion between Ca films and Si substrate because of the possible existence of the relation between silicene buckled structure in CaSi2 film and the composition ratio. The interdiffusion is controlled by introducing hydrogen-terminated layer as an interface layer between Ca and Si substrate, resulting in the control of the composition ratio in CaSi2 film. Moreover, we find that the CaSi2 films with different composition ratio exhibit different thermoelectric power factors. This study reveals that introducing the interface layer for interdiffusion control is an effective way to control the composition ratio and to form metastable high-buckled silicene with high power factor.

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“…Recently, it was found that calcium-intercalated silicon atomic layers in CaSi 2 exhibit electronic properties typical of graphene-like materials [ 11 ]. Many scientific groups are currently involved in the research of calcium silicides [ 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 ]. A variety of methods has been proposed to produce calcium silicides with different compositions that exhibit semimetallic or semiconducting properties.…”

Section: Introductionmentioning

confidence: 99%

Radiation-Stimulated Formation of Two-Dimensional Structures Based on Calcium Silicide

et al. 2022

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The formation of CaSi2 polycrystalline structures under the postgrowth electron irradiation of epitaxial CaF2/Si(111) films with embedded thin Si layers was studied. The dependence on the electron exposure time was investigated for two types of structures with different film thicknesses. The optimal conditions for the formation of two-dimensional CaSi2 structures were found. Raman spectra of the structures after a 1 min electron irradiation demonstrated only one pronounced peak corresponding to the vibrations of Si atoms in the plane of the calcium-intercalated two-dimensional Si layer. An increase in the exposure time resulted in the transition from two- to three-dimensional CaSi2 structures having more complex Raman spectra with additional peaks typical of bulk CaSi2 crystals. Based on the results of microscopic studies and transport measurements, a model explaining the observed effects was proposed.

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Thermoelectric power factor enhancement of calcium-intercalated layered silicene by introducing metastable phase

Cited by 10 publications

References 43 publications

Growth of metastable 2H-CaSi₂ films on Si(111) substrates with ultrathin SiO₂ films by solid phase epitaxy

Growth of metastable 2H-CaSi₂ films on Si(111) substrates with ultrathin SiO₂ films by solid phase epitaxy

The effect of interdiffusion during formation of epitaxial Ca intercalated layered silicene film on its thermoelectric power factor

Radiation-Stimulated Formation of Two-Dimensional Structures Based on Calcium Silicide

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Thermoelectric power factor enhancement of calcium-intercalated layered silicene by introducing metastable phase

Cited by 10 publications

References 43 publications

Growth of metastable 2H-CaSi2 films on Si(111) substrates with ultrathin SiO2 films by solid phase epitaxy

Growth of metastable 2H-CaSi2 films on Si(111) substrates with ultrathin SiO2 films by solid phase epitaxy

The effect of interdiffusion during formation of epitaxial Ca intercalated layered silicene film on its thermoelectric power factor

Radiation-Stimulated Formation of Two-Dimensional Structures Based on Calcium Silicide

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Growth of metastable 2H-CaSi₂ films on Si(111) substrates with ultrathin SiO₂ films by solid phase epitaxy

Growth of metastable 2H-CaSi₂ films on Si(111) substrates with ultrathin SiO₂ films by solid phase epitaxy