Anti-site defect effect on the electronic structure of a Bi<sub>2</sub>Te<sub>3</sub> topological insulator

Chuang, Po-Yu; Su, Shu Hsuan; Chong, Cheong Wei; Chen, Yi Fan; Chou, Yu Heng; Huang, Jie; Chen, Wei Chuan; Cheng, Cheng Maw; Tsuei, Ku Ding; Wang, Chia Hsin; Yang, Yaw Wen; Liao, Yen Fa; Weng, Shih Chang; Lee, Jyh Fu; Lan, Yi-Kang; Chang, Shen Lin; Lee, Chi Hsuan; Yang, Chih Kai; Su, Hailin; Wu, Yu Cheng

doi:10.1039/c7ra08995c

Cited by 48 publications

(39 citation statements)

References 31 publications

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“…[ 12–14,27–29 ] So far, three important aspects regarding the transport properties could be identified in Bi 2 Te 3 ‐based thin films. (1) Atomic defect engineering: defect formation energy calculations and advanced experimental characterizations have revealed [ 101,119–123 ] that vacancies at the anion sites (V Se and V Te ) and anti‐site defects at both anion and cation sites (Bi Te , Sb Te , and Te Bi ) have the lowest formation energies and thus are the dominant atomic defects in thin Bi 2 Te 3 ‐based films. The manipulation of atomic defects and their density is crucial for the optimization of the PF of the films, as will be clarified in Sections 3 and 4.…”

Section: Fabrication and Te Properties Of Bi2te3‐based Filmsmentioning

confidence: 99%

A comprehensive review on Bi₂Te₃‐based thin films: Thermoelectrics and beyond

Tang

Liu

et al. 2022

Interdisciplinary Materials

174

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Bi2Te3‐based materials are not only the most important and widely used room temperature thermoelectric (TE) materials but are also canonical examples of topological insulators in which the topological surface states are protected by the time‐reversal symmetry. High‐performance thin films based on Bi2Te3 have attracted worldwide attention during the past two decades due primarily to their outstanding TE performance as highly efficient TE coolers and as miniature and flexible TE power generators for a variety of electronic devices. Moreover, intriguing topological phenomena, such as the quantum anomalous Hall effect and topological superconductivity discovered in Bi2Te3‐based thin films and heterostructures, have shaped research directions in the field of condensed matter physics. In Bi2Te3‐based films and heterostructures, delicate control of the carrier transport, film composition, and microstructure are prerequisites for successful device operations as well as for experimental verification of exotic topological phenomena. This review summarizes the recent progress made in atomic defect engineering, carrier tuning, and band engineering down to a nanoscale regime and how it relates to the growth and fabrication of high‐quality Bi2Te3‐based films. The review also briefly discusses the physical insight into the exciting field of topological phenomena that were so dramatically realized in Bi2Te3‐ and Bi2Se3‐based structures. It is expected that Bi2Te3‐based thin films and heterostructures will play an ever more prominent role as flexible TE devices collecting and converting low‐level (body) heat into electricity for numerous electronic applications. It is also likely that such films will continue to be a remarkable platform for the realization of novel topological phenomena.

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Section: Fabrication and Te Properties Of Bi2te3‐based Filmsmentioning

confidence: 99%

A comprehensive review on Bi₂Te₃‐based thin films: Thermoelectrics and beyond

Tang

Liu

et al. 2022

Interdisciplinary Materials

174

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“…As a result of further annealing at 200 °C, n decreased slightly from 2.2 × 10 20 to 1.3 × 10 20 cm −3 , which is related to the increased crystallinity and the reduction of Te Bi point defects. [ 40,41 ] During cooling, a semiconducting behavior was observed, analogous to electrical conductivity. In contrast, μ increased during annealing at 200 °C.…”

Section: Resultsmentioning

confidence: 99%

“…The decreased n is related to increased crystallinity, the evaporation of Te, and with that the reduction of Te Bi antiside defects in the polycrystalline film. [ 40 ] The carrier concentration at RT decreased from 10 × 10 20 to 0.4 × 10 20 cm −3 after annealing at 300 °C and decreased exponentially with decreasing temperature. μ in dependency of the temperature is shown in Figure 4c.…”

Section: Resultsmentioning

confidence: 99%

Study of the Annealing Effects of Sputtered Bi₂Te₃Thin Films with Full Thermoelectric Figure of Merit Characterization

Naumochkin

Park

Nielsch

et al. 2021

Physica Rapid Research Ltrs

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Micro‐thermoelectric (TE) devices have a great potential for future applications in the field of energy harvesting to power autonomous sensors. Bi2Te3 sputtered at elevated substrate temperatures exhibits a high figure of merit (ZT) suitable for the fabrication of micro‐TE devices. However, a lift‐off process that does not allow higher substrate temperatures is often used, and although Bi2Te3 is a well‐studied TE material, it lacks full ZT characterization of thin films. Herein, the full TE characterization of sputtered Bi2Te3 thin films is presented, including the charge carrier concentration and mobility, which are deposited at room temperature and postannealed between 150 and 300 °C. The influence of the annealing time and temperature is investigated on a 90 nm‐thick Bi2Te3 film. A maximum ZT of 0.20 is found, which results from the increasing crystallinity and reduction of point defects. To investigate the thickness dependency, Bi2Te3 films with thicknesses of 90, 170, 350, and 470 nm are annealed at 250 °C. A maximum ZT value of 0.26 is observed for the 350 nm Bi2Te3 film. Furthermore, it can be shown that with increasing film thickness, the annealing time has to be increased to maximize ZT.

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“…Figure 4b,c displays the band-mapping results of a MnBi2Te4 sample along direction Г-K and the second derivative of the photoemission intensity, respectively. A Dirac point of MnBi2Te4 was identified in the band gap and differed from the Dirac point buried in the valence band for Bi2Te3 [37,52]. The Fermi level was located above the Dirac point and crossed the bulk conduction band (BCB), indicating that the charge carriers were mainly n-type.…”

Section: Band Structurementioning

confidence: 94%

Epitaxial Growth and Structural Characterizations of MnBi2Te4 Thin Films in Nanoscale

Chang

Chuang

et al. 2021

Nanomaterials

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The intrinsic magnetic topological insulator MnBi2Te4 has attracted much attention due to its special magnetic and topological properties. To date, most reports have focused on bulk or flake samples. For material integration and device applications, the epitaxial growth of MnBi2Te4 film in nanoscale is more important but challenging. Here, we report the growth of self-regulated MnBi2Te4 films by the molecular beam epitaxy. By tuning the substrate temperature to the optimal temperature for the growth surface, the stoichiometry of MnBi2Te4 becomes sensitive to the Mn/Bi flux ratio. Excessive and deficient Mn resulted in the formation of a MnTe and Bi2Te3 phase, respectively. The magnetic measurement of the 7 SL MnBi2Te4 film probed by the superconducting quantum interference device (SQUID) shows that the antiferromagnetic order occurring at the Néel temperature 22 K is accompanied by an anomalous magnetic hysteresis loop along the c-axis. The band structure measured by angle-resolved photoemission spectroscopy (ARPES) at 80 K reveals a Dirac-like surface state, which indicates that MnBi2Te4 has topological insulator properties in the paramagnetic phase. Our work demonstrates the key growth parameters for the design and optimization of the synthesis of nanoscale MnBi2Te4 films, which are of great significance for fundamental research and device applications involving antiferromagnetic topological insulators.

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Anti-site defect effect on the electronic structure of a Bi₂Te₃ topological insulator

Abstract: Tuning the Fermi level (EF) in Bi2Te3 topological-insulator (TI) films is demonstrated on controlling the temperature of growth with molecular-beam epitaxy (MBE).

Cited by 48 publications

References 31 publications

A comprehensive review on Bi₂Te₃‐based thin films: Thermoelectrics and beyond

A comprehensive review on Bi₂Te₃‐based thin films: Thermoelectrics and beyond

Study of the Annealing Effects of Sputtered Bi₂Te₃Thin Films with Full Thermoelectric Figure of Merit Characterization

Epitaxial Growth and Structural Characterizations of MnBi2Te4 Thin Films in Nanoscale

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Anti-site defect effect on the electronic structure of a Bi2Te3 topological insulator

Abstract: Tuning the Fermi level (EF) in Bi2Te3 topological-insulator (TI) films is demonstrated on controlling the temperature of growth with molecular-beam epitaxy (MBE).

Cited by 48 publications

References 31 publications

A comprehensive review on Bi2Te3‐based thin films: Thermoelectrics and beyond

A comprehensive review on Bi2Te3‐based thin films: Thermoelectrics and beyond

Study of the Annealing Effects of Sputtered Bi2Te3Thin Films with Full Thermoelectric Figure of Merit Characterization

Epitaxial Growth and Structural Characterizations of MnBi2Te4 Thin Films in Nanoscale

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Anti-site defect effect on the electronic structure of a Bi₂Te₃ topological insulator

A comprehensive review on Bi₂Te₃‐based thin films: Thermoelectrics and beyond

A comprehensive review on Bi₂Te₃‐based thin films: Thermoelectrics and beyond

Study of the Annealing Effects of Sputtered Bi₂Te₃Thin Films with Full Thermoelectric Figure of Merit Characterization