Effects of homogeneous irradiation of electron beam on crystal growth and thermoelectric properties of nanocrystalline bismuth selenium telluride thin films

Takashiri, Masayuki; Imai, Kazuo; Uyama, Masato; Hagino, Harutoshi; Tanaka, Saburo; Miyazaki, Kôji; Nishi, Yoshitake

doi:10.1016/j.jallcom.2014.05.146

Cited by 36 publications

(12 citation statements)

References 30 publications

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“…According to Vegard's law, these peak positions correspond to the peaks from the alloys with atomic compositions of Bi 2 Te 3 and (Bi 2 Te 3 ) 0.8 (Bi 2 Se 3 ) 0.2 , respectively. The atomic composition of as-grown thin films (unannealed, 0 MGy dose) was (Bi 2 Te 3 ) 0.9 (Bi 2 Se 3 ) 0.1 , and we confirmed the atomic composition did not change significantly after EB irradiation (1.07 MGy) 24 and thermal annealing (300 C). 26 Therefore, we conclude that the original alloy, (Bi 2 Te 3 ) 0.9 (Bi 2 Se 3 ) 0.1 , transformed into Bi 2 Te 3 and (Bi 2 Te 3 ) 0.8 (Bi 2 Se 3 ) 0.2 as a result of the two-step method and this transformation satisfied the law of conservation of mass.…”

Section: Resultssupporting

confidence: 68%

“…24 We will refer to the thin films that have not undergone EB irradiation treatment as having an EB irradiation dose of 0 MGy. Additionally, we will occasionally refer to the thin film treated with EB irradiation alone as the unannealed thin films, and the thin films with two-step process as the annealed thin films.…”

Section: Resultsmentioning

confidence: 99%

“…[22][23][24] A tungsten filament in a vacuum was used to generate an EB with a voltage of 0.17 MeV and irradiation doses between 0 and 1.07 MGy. We estimate that the temperature increased by approximately 25 K at maximum in this EB irradiation dose range.…”

Section: Methodsmentioning

confidence: 99%

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Enhanced thermoelectric properties of phase-separating bismuth selenium telluride thin films via a two-step method

Takashiri

Kurita

Hagino

et al. 2015

Journal of Applied Physics

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Section: Resultssupporting

confidence: 68%

Section: Resultsmentioning

confidence: 99%

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Enhanced thermoelectric properties of phase-separating bismuth selenium telluride thin films via a two-step method

Takashiri

Kurita

Hagino

et al. 2015

Journal of Applied Physics

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“…This was followed by a homogeneous electron beam (EB) irradiation treatment, which is known not to signi cantly enlarge the crystallite size. 19,20) X-ray diffraction (XRD) patterns were used to determine the crystal orientation (Lotgering factor, F value) and crystallite size of the thin lms, as well as the strain induced within them. We measured the in-plane electrical conductivity and Seebeck coef cient at RT.…”

Section: Introductionmentioning

confidence: 99%

Anisotropic Analysis of Nanocrystalline Bismuth Telluride Thin Films Treated by Homogeneous Electron Beam Irradiation

et al. 2017

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The in-plane and cross-plane transport properties of nanocrystalline bismuth telluride (Bi 2 Te 3 ) thin lms were evaluated to analyze their anisotropic behavior. Bi 2 Te 3 thin lms were prepared via radio frequency (RF) magnetron sputtering, followed by a subsequent treatment of thermal annealing and homogeneous electron beam (EB) irradiation at various EB doses. The crystallographic properties of the thin lms were determined by X-ray diffraction (XRD) analysis. It was determined that the crystal orientation (Lotgering factor; F value) of Bi 2 Te 3 thin lms can be controlled by homogeneous EB irradiation treatments, without resulting in crystal growth. The electrical conductivity and Seebeck coefcient were measured in the in-plane direction of the lms, and the thermal conductivity was measured in the cross-plane direction using the 3ω method. The anisotropic analysis was performed by combining the F value of the thin lms with a simple model based on the transport properties of the basal and lateral planes of single-and poly-crystal Bi 2 Te 3 . The electrical and thermal conductivities of the in-plane and cross-plane directions of the EB-irradiated thin lms clearly differed; however, there was no signi cant difference between the Seebeck coef cient values of the two planes. Finally, we determined that the gure of merit, ZT, was enhanced by the homogeneous EB irradiation treatment, and the inplane ZT value was 25% greater than that of the cross-plane direction.

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“…Since then, research in bismuth telluride-based alloy thin films formed by electrodeposition has received much attention owing to the improvement in thermoelectric properties under the established experimental conditions [16][17][18]. To further improve the thermoelectric performance, deposited films must be subjected to additional treatment such as thermal annealing [9,19], electron beam irradiation [20][21][22], and pulsed laser annealing [23,24]. In particular, thermal annealing is well investigated in bismuth telluride-based alloy thin films, and has been demonstrated to greatly improve thermoelectric properties [25][26][27].…”

Section: Introductionmentioning

confidence: 99%

Effect of thermal annealing on the structural and thermoelectric properties of electrodeposited antimony telluride thin films

Hatsuta

Takemori

Takashiri

2016

Journal of Alloys and Compounds

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Please cite this article as: N. Hatsuta, D. Takemori, M. Takashiri, Effect of thermal annealing on the structural and thermoelectric properties of electrodeposited antimony telluride thin films, Journal of Alloys and Compounds (2016), ABSTRACTWe investigated the effect of thermal annealing on structural and thermoelectric properties of p-type antimony telluride (Sb 2 Te 3 ) thin films fabricated on a stainless steel (SUS304) substrate by electrodeposition. Antimony telluride thin films were annealed for 1 h at temperatures between 200 and 400°C. We observed that the as-deposited thin film and thin films annealed at temperatures less than 250°C possessed a stoichiometric atomic composition (Sb:Te = 40:60) with no impurities from the substrate. At the annealing temperature of 300°C, we observed a certain amount of impurities (Fe, Cr, Ni) in the thin film. The Seebeck coefficient was decreased but the electrical conductivity was increased for films treated at 300°C. As a result, the thin film exhibited a maximum power factor of 13.6 µW/(cm·K 2 ). On further increasing the annealing temperature to 400°C, the film structure and thermoelectric properties were drastically changed. The impurity concentration in the thin film reached approximately 50 at%. The crystal structure of Sb 2 Te 3 completely disappeared, and instead, other chemical compounds formed by alloying the elements of the thin film and the substrate were observed.

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Effects of homogeneous irradiation of electron beam on crystal growth and thermoelectric properties of nanocrystalline bismuth selenium telluride thin films

Cited by 36 publications

References 30 publications

Enhanced thermoelectric properties of phase-separating bismuth selenium telluride thin films via a two-step method

Enhanced thermoelectric properties of phase-separating bismuth selenium telluride thin films via a two-step method

Anisotropic Analysis of Nanocrystalline Bismuth Telluride Thin Films Treated by Homogeneous Electron Beam Irradiation

Effect of thermal annealing on the structural and thermoelectric properties of electrodeposited antimony telluride thin films

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