Nanomechanical properties of Bi2Te3 thin films by nanoindentation

Tasi, Cheng Hsun; Tseng, Yu Chin; Jian, Sheng-Rui; Liao, Ying-Yen; Lin, Chih Ming; Yang, Ping; Chen, Dao Long; Chen, Hsueh Ju; Luo, Chih-Wei; Juang, Jenh‐Yih

doi:10.1016/j.jallcom.2014.09.028

Cited by 26 publications

(19 citation statements)

References 41 publications

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“…Bismuth telluride (Bi 2 Te 3 )-based TE alloys exhibit the lowest and highest reported elastic modulus values, as low as ~40 GPa and up to ~200 GPa, depending on the exact alloying and fabrication procedure [12,18]. Lead telluride (PbTe)-based alloys (which is the most researched alloy system) exhibit modulus values of ~60 GPa [1].…”

Section: Elastic Modulusmentioning

confidence: 99%

Mechanical Properties of Thermoelectric Materials for Practical Applications

Guttmann¹,

Gelbstein²

2018

Bringing Thermoelectricity Into Reality

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Thermoelectric (TE) direct conversion of thermal energy into electricity is a novel renewable energy conversion method currently at a technological readiness level of 3-5 approaching laboratory prototypes. While approaching practical thermoelectric devices, an increase in the thermoelectric element's efficiency is needed at the entire service temperature range. Yet, the main focus of research was concentrated on the electronic properties of the materials, while research on the mechanical properties was left behind. As it is shown in this chapter, knowing and controlling the mechanical properties of TE materials are paramount necessities for approaching practical TEGs. The material's elastic constants, strength and fracture toughness are the most crucial parameters for designing of practical devices. The elastic constants provide understanding about the material's stiffness, while strength provides the loading conditions in which the material will keep its original shape. Knowing the fracture toughness provides the stress envelope in which the material could operate and its susceptibility to inherent fabrication faults. The characterization methods of these properties are varied and may be physical or pure mechanical in nature. It is the authors opinion to prefer the mechanical methods, so the results obtained will describe more accurately the material's response to mechanical loading.

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Section: Elastic Modulusmentioning

confidence: 99%

Mechanical Properties of Thermoelectric Materials for Practical Applications

Guttmann¹,

Gelbstein²

2018

Bringing Thermoelectricity Into Reality

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“…However, the occurrence of vacancies shifts the Fermi level from the bulk band gap and induces the formation of BiO bonds , while surface oxidation implies the degradation of the peculiar electronic properties of TIs . Moreover, crystal defects, whose amount is relatively large in some of the above‐mentioned growth processes, could also have a detrimental effect on the mechanical properties . Therefore, TIs displaying high amount of crystal defects cannot be successfully employed in technological applications.…”

Section: Introductionmentioning

confidence: 99%

“…Previous related works on Bi 2 Te 3 TIs were mostly focused on the optoelectronic and thermoelectric properties , while there is a relative lack of research efforts devoted to the mechanical characterization. Indeed, only a few contributions addressed this topic and analyzed Bi 2 Te 3 nanosheets and thin films , while none of them dealt with Bi 2 Te 3 single crystals. However, knowledge of the mechanical properties is required in order to design structural/functional elements operating at the nanoscale, such as nanoelectromechanical systems (NEMS), flexible electronics devices , and TI‐based mechanical metamaterials .…”

Section: Introductionmentioning

confidence: 99%

Nanoindentation of single‐crystal Bi₂Te₃ topological insulators grown with the Bridgman–Stockbarger method

Lamuta

Cupolillo

Politano

et al. 2016

Physica Status Solidi (b)

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In this work, bismuth telluride (Bi 2 Te 3 ) single crystals were grown from melted polycrystalline Bi-Te material using the Bridgman-Stockbarger method. Crystalline quality and surface chemistry were investigated through X-ray diffraction analysis and X-ray photoelectron spectroscopy. The mechanical properties were investigated by means of depth-sensing nanoindentation tests carried out using the continuous stiffness measurement (CSM) technique. In turn, the distribution of material hardness and Young's modulus in the depth direction (i.e., perpendicular to the single crystal basal plane) were resolved and quantitative comparisons with the available data extracted from previous literature works were drawn. It is shown that the obtained single crystals are free of contaminants and/or oxide phases and that the mechanical properties lie between those reported in recent literature for Bi 2 Te 3 polycrystalline thin films and 2D nanosheets.

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“…The elastic modulus (Ei) and Poisson ratio (υi) of the Berkovich indenter used in this study were 1141 GPa and 0.07, respectively [34]. The υf was assumed to be 0.25 by referencing the Poisson’s ratio of thin films [29,41,42].…”

Section: Resultsmentioning

confidence: 99%

Nanomechanical and Material Properties of Fluorine-Doped Tin Oxide Thin Films Prepared by Ultrasonic Spray Pyrolysis: Effects of F-Doping

Tuyen

Tiên

2019

Materials

Self Cite

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Fluorine-doped tin oxide (FTO) thin films were deposited on glass substrates using ultrasonic spray pyrolysis (USP) at a fixed substrate temperature of 400 °C and various Fluorine/Tin (F/Sn) atomic ratios of 0, 0.1, 0.5, and 1.0. Effects of F/Sn atomic ratios on structural-morphological, compositional, electrical, optical, and nanomechanical properties of the FTO thin films were systematically studied. The FTO films exhibited a tetragonal structure with preferred orientations of (110), (200), and (211), and polycrystalline morphology with spear-like or coconut shell-like particles on the surfaces. The presence of F-doping was confirmed by XPS results with clear F1s peaks, and F-concentration was determined to be 0.7% for F/Sn = 0.1 and 5.1% for F/Sn = 0.5. Moreover, the resistivity of FTO films reduced remarkably from 4.1 mΩcm at F/Sn = 0 to 0.7 mΩcm at F/Sn = 1, primarily due to the corresponding increase of carrier concentration from 2 × 1020 cm−3 to 1.2 × 1021 cm−3. The average optical transmittance of the films prepared at F/Sn of 0–0.5 was over 90%, and it decreased to 84.4% for the film prepared at F/Sn = 1. The hardness (H) and Young’s modulus (E) of the FTO films increased when the F/Sn ratios increased from 0 to 0.5, reaching maximum values of H = 12.3 ± 0.4 GPa, E = 131.7 ± 8.0 GPa at F/Sn = 0.5. Meanwhile, the H and E reduced considerably when the F/Sn ratio further increased to 1.0, following the inverse Hall-Petch effect approximately, suggesting that the grain boundary effect played a primary role in manipulating the nanomechanical properties of the FTO films. Furthermore, favorable mechanical properties with large H/Ef and H 3 / E f 2 ratios were found for the FTO film prepared at F/Sn = 0.5, which possessed high crystallinity, large grain size, and compact morphology.

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Nanomechanical properties of Bi2Te3 thin films by nanoindentation

Cited by 26 publications

References 41 publications

Mechanical Properties of Thermoelectric Materials for Practical Applications

Mechanical Properties of Thermoelectric Materials for Practical Applications

Nanoindentation of single‐crystal Bi₂Te₃ topological insulators grown with the Bridgman–Stockbarger method

Nanomechanical and Material Properties of Fluorine-Doped Tin Oxide Thin Films Prepared by Ultrasonic Spray Pyrolysis: Effects of F-Doping

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Nanomechanical properties of Bi2Te3 thin films by nanoindentation

Cited by 26 publications

References 41 publications

Mechanical Properties of Thermoelectric Materials for Practical Applications

Mechanical Properties of Thermoelectric Materials for Practical Applications

Nanoindentation of single‐crystal Bi2Te3 topological insulators grown with the Bridgman–Stockbarger method

Nanomechanical and Material Properties of Fluorine-Doped Tin Oxide Thin Films Prepared by Ultrasonic Spray Pyrolysis: Effects of F-Doping

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Nanoindentation of single‐crystal Bi₂Te₃ topological insulators grown with the Bridgman–Stockbarger method