Positive conductivity type in bismuth film

Inoue, Masasi; Yagi, Hisao

doi:10.1007/bf00896612

Cited by 9 publications

(3 citation statements)

References 7 publications

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“…In 2D materials, the electronic states are distributed in a quantized manner, resulting in broadening band gap and increasing Seebeck coefficient [2], when the thickness decreases to a critical point based on quantum confinement effect [10][11][12]. Measured Seebeck coefficients of our 2D bismuth can go up to −237 µV K −1 , which is 2-5 times higher than reported values on thin film [29] or bulk bismuth [4,14]. To the best of our knowledge, this is the first experimental evidence to prove that scaling down to 2D scale can significantly enhance Seebeck coefficient of bismuth.…”

Section: Resultsmentioning

confidence: 52%

Anisotropic thermoelectric effect and field-effect devices in epitaxial bismuthene on Si (111)

Zhong

Zhao²,

Zhu³

et al. 2020

Nanotechnology

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This experimental study reveals intriguing thermoelectric effects and devices in epitaxial bismuthene, two-dimensional (2D) bismuth with thickness ⩽30 nm, on Si (111). Bismuthene exhibits interesting anisotropic Seebeck coefficients varying 2–5 times along different crystal orientations, implying the existence of a puckered atomic structure like black phosphorus. An absolute value of Seebeck coefficient up to 237 μV K−1 sets a record for elemental Bi ever measured to the best of our knowledge. Electrical conductivity of bismuthene can reach up to 4.6 × 104 S m−1, which is sensitive to thickness and magnetic field. Along with a desired low thermal conductivity ∼1.97 W m−1 K that is 20% of its bulk form, the first experimental zT value at room temperature for bismuthene was measured ∼10–2, which is much higher than many other VA Xenes and comparable to its bulk compounds. Above results suggest a mixed buckled and puckered Bi atomic structure for epitaxial 2D bismuth on Si (111). Our work paves the way to explore potential applications, such as heat flux sensor, energy converting devices and so on for bismuthene.

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Section: Resultsmentioning

confidence: 52%

Anisotropic thermoelectric effect and field-effect devices in epitaxial bismuthene on Si (111)

Zhong

Zhao²,

Zhu³

et al. 2020

Nanotechnology

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“…In the case of bismuth (~2 = 1 eV, a = 7 À and m* = 0.16 x mo) this expression is : 4.2 HALL CONSTANT RH. -Figure 9 summarizes some results obtained for the Hall Constant value as a function of temperature for unannealed films (process n° 1) deposited on different types of substrates and from different authors [12,13]. A general feature of these results is the change in the sign of RH for temperatures ranging between 100 K to 200 K. Fig.…”

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confidence: 91%

“…thickness which is in marked contrast with the main conclusion of the structural study. More recently, however, Inoue et al [12,15] and Kochowski et al [13] have interpreted this result by the presence of surface states formed during condensation of the films. The respective values of ny' and p03BC2h govem the sign of RH in :…”

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confidence: 99%

Structural study of bismuth films and its consequences on their electrical properties

Buxo

Saleh

Sarrabayrouse

et al. 1980

Rev. Phys. Appl. (Paris)

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2014 Les auteurs étudient les propriétés structurales des couches minces de bismuth à 1'aide des techniques suivantes : diffraction des électrons par réftexion, diffraction des rayons X, microscopie électronique par balayage et diffraction et microscopie électronique par transmission. Ils rappellent les propriétés électriques des couches minces de bismuth (mesures de conductivité et du facteur RH). Il apparait que les états de surface jouent un rôle déterminant dans les définitions des propriétés du facteur RH et de la conductivité. Cette conclusion est étayée par les résultats de 1'etude structurale. Une propriété importante du mécanisme de conduction telle que le libre parcours moyen des porteurs a été estimée et sa valeur est aussi en accord avec les résultats de l'étude structurale.La densité des états de surface ainsi que la hauteur de barrière associée aux joints de grain ont été évaluées en fonction des différentes techniques de preparation. Abstract. 2014 The structure of bismuth thin films prepared according to three different deposition techniques is inspected by : reflection electron diffraction, X-ray diffraction, scanning electron microscopy, transmission microscopy and electron diffraction. The electrical conduction properties, RH and conductance measurements, of these films are then discussed. It appears that surface states play a major role in dictating the properties of both RH and conductivity. This is clearly confirmed with the aid of the conclusions of the structural study. By comparing size effect theories with the conductivity data the carrier mean free path can be estimated to be of the order of 1 000 Å in good agreement with the observation of the film structure. The surface state density and the energy barrier that controls the carrier transport across the grain boundaries have also been evaluated as a function of the preparation technique.

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