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Surendran M, Singh S, Chen H, Wu C, Avishai A, Shao YT, Ravichandran J. A Hybrid Pulsed Laser Deposition Approach to Grow Thin Films of Chalcogenides. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024; 36:e2312620. [PMID: 38288906 DOI: 10.1002/adma.202312620] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2023] [Revised: 01/24/2024] [Indexed: 02/13/2024]
Abstract
Vapor-pressure mismatched materials such as transition metal chalcogenides have emerged as electronic, photonic, and quantum materials with scientific and technological importance. However, epitaxial growth of vapor-pressure mismatched materials are challenging due to differences in the reactivity, sticking coefficient, and surface adatom mobility of the mismatched species constituting the material, especially sulfur containing compounds. Here, a novel approach is reported to grow chalcogenides-hybrid pulsed laser deposition-wherein an organosulfur precursor is used as a sulfur source in conjunction with pulsed laser deposition to regulate the stoichiometry of the deposited films. Epitaxial or textured thin films of sulfides with variety of structure and chemistry such as alkaline metal chalcogenides, main group chalcogenides, transition metal chalcogenides, and chalcogenide perovskites are demonstrated, and structural characterization reveal improvement in thin film crystallinity, and surface and interface roughness compared to the state-of-the-art. The growth method can be broadened to other vapor-pressure mismatched chalcogenides such as selenides and tellurides. This work opens up opportunities for broader epitaxial growth of chalcogenides, especially sulfide-based thin film technological applications.
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Affiliation(s)
- Mythili Surendran
- Mork Family Department of Chemical Engineering and Materials Science, and Core Center for Excellence in Nano Imaging, University of Southern California, 925 Bloom Walk, Los Angeles, CA, 90089, USA
| | - Shantanu Singh
- Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, 925 Bloom Walk, Los Angeles, CA, 90089, USA
| | - Huandong Chen
- Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, 925 Bloom Walk, Los Angeles, CA, 90089, USA
| | - Claire Wu
- Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, 925 Bloom Walk, Los Angeles, CA, 90089, USA
| | - Amir Avishai
- Core Center for Excellence in Nano Imaging, University of Southern California, 925 Bloom Walk, Los Angeles, CA, 90089, USA
| | - Yu-Tsun Shao
- Mork Family Department of Chemical Engineering and Materials Science, and Core Center for Excellence in Nano Imaging, University of Southern California, 925 Bloom Walk, Los Angeles, CA, 90089, USA
| | - Jayakanth Ravichandran
- Mork Family Department of Chemical Engineering and Materials Science, Core Center for Excellence in Nano Imaging and Ming Hsieh Department of Electrical and Computer Engineering, University of Southern California, 925 Bloom Walk, Los Angeles, CA, 90089, USA
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2
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Pandey L, Husain S, Barwal V, Hait S, Gupta NK, Mishra V, Kumar N, Sharma N, Dixit D, Singh V, Chaudhary S. Topological transport properties of highly oriented Bi 2Te 3thin film deposited by sputtering. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2023; 35:355702. [PMID: 37172602 DOI: 10.1088/1361-648x/acd50a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Accepted: 05/12/2023] [Indexed: 05/15/2023]
Abstract
Topological insulators (TIs) are the promising materials for next-generation technology due to their exotic features such as spin momentum locking, conducting surface states, etc. However, the high-quality growth of TIs by sputtering technique, which is one of the foremost industrial requirements, is extremely challenging. Also, the demonstration of simple investigation protocols to characterize topological properties of TIs using electron-transport methods is highly desirable. Here, we report the quantitative investigation of non-trivial parameters employing magnetotransport measurements on a prototypical highly textured Bi2Te3TI thin film prepared by sputtering. Through the systematic analyses of the temperature and magnetic field dependent resistivity, all topological parameters associated with TIs, such as coherency factorα, Berry phase (ΦB), mass term (m), the dephasing parameter (p), slope of temperature dependent conductivity correction (κ) and the surface state penetration depth (λ) are estimated by using the modified 'Hikami-Larkin-Nagaoka', 'Lu-Shen' and 'Altshuler-Aronov' models. The obtained values of topological parameters are well comparable to those reported on molecular beam epitaxy grown TIs. The epitaxial growth of Bi2Te3film using sputtering, and investigation of the non-trivial topological states from its electron-transport behavior are important for their fundamental understanding and technological applications.
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Affiliation(s)
- Lalit Pandey
- Thin Film Laboratory, Department of Physics, Indian Institute of Technology Delhi, New Delhi 110016, India
| | - Sajid Husain
- Thin Film Laboratory, Department of Physics, Indian Institute of Technology Delhi, New Delhi 110016, India
| | - Vineet Barwal
- Thin Film Laboratory, Department of Physics, Indian Institute of Technology Delhi, New Delhi 110016, India
| | - Soumyarup Hait
- Thin Film Laboratory, Department of Physics, Indian Institute of Technology Delhi, New Delhi 110016, India
| | - Nanhe Kumar Gupta
- Thin Film Laboratory, Department of Physics, Indian Institute of Technology Delhi, New Delhi 110016, India
| | - Vireshwar Mishra
- Thin Film Laboratory, Department of Physics, Indian Institute of Technology Delhi, New Delhi 110016, India
| | - Nakul Kumar
- Thin Film Laboratory, Department of Physics, Indian Institute of Technology Delhi, New Delhi 110016, India
| | - Nikita Sharma
- Thin Film Laboratory, Department of Physics, Indian Institute of Technology Delhi, New Delhi 110016, India
| | - Dinesh Dixit
- Central Research Facility, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India
| | - Veer Singh
- Central Research Facility, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India
| | - Sujeet Chaudhary
- Thin Film Laboratory, Department of Physics, Indian Institute of Technology Delhi, New Delhi 110016, India
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3
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Krishnamoorthy HNS, Dubrovkin AM, Adamo G, Soci C. Topological Insulator Metamaterials. Chem Rev 2023; 123:4416-4442. [PMID: 36943013 DOI: 10.1021/acs.chemrev.2c00594] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/23/2023]
Abstract
Confinement of electromagnetic fields at the subwavelength scale via metamaterial paradigms is an established method to engineer light-matter interaction in most common material systems, from insulators to semiconductors and from metals to superconductors. In recent years, this approach has been extended to the realm of topological materials, providing a new avenue to access nontrivial features of their electronic band structure. In this review, we survey various topological material classes from a photonics standpoint, including crystal growth and lithographic structuring methods. We discuss how exotic electronic features such as spin-selective Dirac plasmon polaritons in topological insulators or hyperbolic plasmon polaritons in Weyl semimetals may give rise to unconventional magneto-optic, nonlinear, and circular photogalvanic effects in metamaterials across the visible to infrared spectrum. Finally, we dwell on how these effects may be dynamically controlled by applying external perturbations in the form of electric and magnetic fields or ultrafast optical pulses. Through these examples and future perspectives, we argue that topological insulator, semimetal and superconductor metamaterials are unique systems to bridge the missing links between nanophotonic, electronic, and spintronic technologies.
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Affiliation(s)
- Harish N S Krishnamoorthy
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore
- Centre for Disruptive Photonic Technologies, The Photonic Institute, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore
| | - Alexander M Dubrovkin
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore
- Centre for Disruptive Photonic Technologies, The Photonic Institute, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore
| | - Giorgio Adamo
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore
- Centre for Disruptive Photonic Technologies, The Photonic Institute, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore
| | - Cesare Soci
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore
- Centre for Disruptive Photonic Technologies, The Photonic Institute, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore
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4
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Zhao T, Guo J, Li T, Wang Z, Peng M, Zhong F, Chen Y, Yu Y, Xu T, Xie R, Gao P, Wang X, Hu W. Substrate engineering for wafer-scale two-dimensional material growth: strategies, mechanisms, and perspectives. Chem Soc Rev 2023; 52:1650-1671. [PMID: 36744507 DOI: 10.1039/d2cs00657j] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The fabrication of wafer-scale two-dimensional (2D) materials is a prerequisite and important step for their industrial applications. Chemical vapor deposition (CVD) is the most promising approach to produce high-quality films in a scalable way. Recent breakthroughs in the epitaxy of wafer-scale single-crystalline graphene, hexagonal boron nitride, and transition-metal dichalcogenides highlight the pivotal roles of substrate engineering by lattice orientation, surface steps, and energy considerations. This review focuses on the existing strategies and underlying mechanisms, and discusses future directions in epitaxial substrate engineering to deliver wafer-scale 2D materials for integrated electronics and photonics.
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Affiliation(s)
- Tiange Zhao
- School of Materials, State Key Laboratory of Optoelectronic Materials and Technologies, Sun Yat-sen University, Guangzhou 510275, China. .,State Key Laboratory of Infrared Physics, Shanghai Institute of Technical Physics Chinese Academy of Sciences, 500 Yutian Road, Shanghai 200083, China.
| | - Jiaxiang Guo
- State Key Laboratory of Infrared Physics, Shanghai Institute of Technical Physics Chinese Academy of Sciences, 500 Yutian Road, Shanghai 200083, China.
| | - Taotao Li
- National Laboratory of Solid State Microstructures, School of Electronic Science and Engineering and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, China.
| | - Zhen Wang
- State Key Laboratory of Infrared Physics, Shanghai Institute of Technical Physics Chinese Academy of Sciences, 500 Yutian Road, Shanghai 200083, China.
| | - Meng Peng
- State Key Laboratory of Infrared Physics, Shanghai Institute of Technical Physics Chinese Academy of Sciences, 500 Yutian Road, Shanghai 200083, China.
| | - Fang Zhong
- State Key Laboratory of Infrared Physics, Shanghai Institute of Technical Physics Chinese Academy of Sciences, 500 Yutian Road, Shanghai 200083, China.
| | - Yue Chen
- State Key Laboratory of Infrared Physics, Shanghai Institute of Technical Physics Chinese Academy of Sciences, 500 Yutian Road, Shanghai 200083, China.
| | - Yiye Yu
- State Key Laboratory of Infrared Physics, Shanghai Institute of Technical Physics Chinese Academy of Sciences, 500 Yutian Road, Shanghai 200083, China.
| | - Tengfei Xu
- State Key Laboratory of Infrared Physics, Shanghai Institute of Technical Physics Chinese Academy of Sciences, 500 Yutian Road, Shanghai 200083, China.
| | - Runzhang Xie
- State Key Laboratory of Infrared Physics, Shanghai Institute of Technical Physics Chinese Academy of Sciences, 500 Yutian Road, Shanghai 200083, China.
| | - Pingqi Gao
- School of Materials, State Key Laboratory of Optoelectronic Materials and Technologies, Sun Yat-sen University, Guangzhou 510275, China.
| | - Xinran Wang
- National Laboratory of Solid State Microstructures, School of Electronic Science and Engineering and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, China. .,School of Integrated Circuits, Nanjing University, Suzhou, China.,Suzhou Laboratory, Suzhou, China
| | - Weida Hu
- State Key Laboratory of Infrared Physics, Shanghai Institute of Technical Physics Chinese Academy of Sciences, 500 Yutian Road, Shanghai 200083, China.
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5
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Jalil AR, Schüffelgen P, Valencia H, Schleenvoigt M, Ringkamp C, Mussler G, Luysberg M, Mayer J, Grützmacher D. Selective Area Epitaxy of Quasi-1-Dimensional Topological Nanostructures and Networks. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:354. [PMID: 36678107 PMCID: PMC9863233 DOI: 10.3390/nano13020354] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 01/11/2023] [Accepted: 01/12/2023] [Indexed: 06/17/2023]
Abstract
Quasi-one-dimensional (1D) topological insulators hold the potential of forming the basis of novel devices in spintronics and quantum computing. While exposure to ambient conditions and conventional fabrication processes are an obstacle to their technological integration, ultra-high vacuum lithography techniques, such as selective area epitaxy (SAE), provide all the necessary ingredients for their refinement into scalable device architectures. In this work, high-quality SAE of quasi-1D topological insulators on templated Si substrates is demonstrated. After identifying the narrow temperature window for selectivity, the flexibility and scalability of this approach is revealed. Compared to planar growth of macroscopic thin films, selectively grown regions are observed to experience enhanced growth rates in the nanostructured templates. Based on these results, a growth model is deduced, which relates device geometry to effective growth rates. After validating the model experimentally for various three-dimensional topological insulators (3D TIs), the crystal quality of selectively grown nanostructures is optimized by tuning the effective growth rates to 5 nm/h. The high quality of selectively grown nanostructures is confirmed through detailed structural characterization via atomically resolved scanning transmission electron microscopy (STEM).
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Affiliation(s)
- Abdur Rehman Jalil
- Peter Grünberg Institute (PGI-9), Forschungszentrum Jülich, 52425 Jülich, Germany
- JARA-FIT (Fundamentals of Future Information Technology), Jülich-Aachen Research Alliance, Forschungszentrum Jülich and RWTH Aachen University, 52425 Jülich, Germany
- Peter Grünberg Institute (PGI-10), JARA-Green IT, Forschungszentrum Jülich, 52425 Jülich, Germany
| | - Peter Schüffelgen
- Peter Grünberg Institute (PGI-9), Forschungszentrum Jülich, 52425 Jülich, Germany
- JARA-FIT (Fundamentals of Future Information Technology), Jülich-Aachen Research Alliance, Forschungszentrum Jülich and RWTH Aachen University, 52425 Jülich, Germany
| | - Helen Valencia
- JARA-FIT (Fundamentals of Future Information Technology), Jülich-Aachen Research Alliance, Forschungszentrum Jülich and RWTH Aachen University, 52425 Jülich, Germany
- Ernst Ruska-Centre (ER-C) for Microscopy and Spectroscopy with Electrons, Forschungszentrum Juelich, 52425 Jülich, Germany
| | - Michael Schleenvoigt
- Peter Grünberg Institute (PGI-9), Forschungszentrum Jülich, 52425 Jülich, Germany
- JARA-FIT (Fundamentals of Future Information Technology), Jülich-Aachen Research Alliance, Forschungszentrum Jülich and RWTH Aachen University, 52425 Jülich, Germany
| | - Christoph Ringkamp
- Peter Grünberg Institute (PGI-9), Forschungszentrum Jülich, 52425 Jülich, Germany
- JARA-FIT (Fundamentals of Future Information Technology), Jülich-Aachen Research Alliance, Forschungszentrum Jülich and RWTH Aachen University, 52425 Jülich, Germany
| | - Gregor Mussler
- Peter Grünberg Institute (PGI-9), Forschungszentrum Jülich, 52425 Jülich, Germany
- JARA-FIT (Fundamentals of Future Information Technology), Jülich-Aachen Research Alliance, Forschungszentrum Jülich and RWTH Aachen University, 52425 Jülich, Germany
| | - Martina Luysberg
- Ernst Ruska-Centre (ER-C) for Microscopy and Spectroscopy with Electrons, Forschungszentrum Juelich, 52425 Jülich, Germany
| | - Joachim Mayer
- Ernst Ruska-Centre (ER-C) for Microscopy and Spectroscopy with Electrons, Forschungszentrum Juelich, 52425 Jülich, Germany
- Central Facility for Electron Microscopy (GFE), RWTH Aachen University, 52074 Aachen, Germany
| | - Detlev Grützmacher
- Peter Grünberg Institute (PGI-9), Forschungszentrum Jülich, 52425 Jülich, Germany
- JARA-FIT (Fundamentals of Future Information Technology), Jülich-Aachen Research Alliance, Forschungszentrum Jülich and RWTH Aachen University, 52425 Jülich, Germany
- Peter Grünberg Institute (PGI-10), JARA-Green IT, Forschungszentrum Jülich, 52425 Jülich, Germany
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6
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Kim D, Yang C, Park YD. Towards More Accurate Determination of the Thermoelectric Properties of Bi 2Se 3 Epifilms by Suspension via Nanomachining Techniques. SENSORS (BASEL, SWITZERLAND) 2022; 22:8042. [PMID: 36298391 PMCID: PMC9609336 DOI: 10.3390/s22208042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Revised: 10/12/2022] [Accepted: 10/19/2022] [Indexed: 06/16/2023]
Abstract
We report on the characterization of the thermoelectric properties of Bi2Se3 epifilms. MBE-grown Bi2Se3 films on GaAs (111) A are nanomachined with integrated Pt elements serving as local joule heaters, thermometers, and voltage probes. We suspended a 4 µm × 120 µm Bi2Se3 by nanomachining techniques. Specifically, we selectively etched GaAs buffer/substrate layers by citric acid solution followed by a critical point drying method. We found that the self-heating 3ω method is an appropriate technique for the accurate measurement of the thermal conductivity of suspended Bi2Se3. The measured thermoelectric properties of 200 nm thick Bi2Se3 at room temperature were κ=1.95 W/m K, S=−102.8 μV/K, σ = 75,581 S/m and the figure of merit was ZT=0.12. The study introduces a method to measure thermal conductivity accurately by suspending thin films.
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Affiliation(s)
- Donguk Kim
- Department of Physics & Astronomy, Seoul National University, Seoul 08858, Korea
| | - Chanuk Yang
- Department of Physics, Research Institute of Physics and Chemistry, Jeonbuk National University, Jeonju 54896, Korea
| | - Yun Daniel Park
- Department of Physics & Astronomy, Seoul National University, Seoul 08858, Korea
- Institute of Applied Physics, Seoul National University, Seoul 08858, Korea
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7
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Li CH, Moon J, van 't Erve OMJ, Wickramaratne D, Cobas ED, Johannes MD, Jonker BT. Spin-Sensitive Epitaxial In 2Se 3 Tunnel Barrier in In 2Se 3/Bi 2Se 3 Topological van der Waals Heterostructure. ACS APPLIED MATERIALS & INTERFACES 2022; 14:34093-34100. [PMID: 35820066 DOI: 10.1021/acsami.2c08053] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Current-generated spin arising from spin-momentum locking in topological insulator (TI) surface states has been shown to switch the magnetization of an adjacent ferromagnet (FM) via spin-orbit torque (SOT) with a much higher efficiency than heavy metals. However, in such FM/TI heterostructures, most of the current is shunted through the FM metal due to its lower resistance, and recent calculations have also shown that topological surface states can be significantly impacted when interfaced with an FM metal such as Ni and Co. Hence, placing an insulating layer between the TI and FM will not only prevent current shunting, therefore minimizing overall power consumption, but may also help preserve the topological surface states at the interface. Here, we report the van der Waals epitaxial growth of β-phase In2Se3 on Bi2Se3 by molecular beam epitaxy and demonstrate its spin sensitivity by the electrical detection of current-generated spin in Bi2Se3 surface states using a Fe/In2Se3 detector contact. Our density functional calculations further confirm that the linear dispersion and spin texture of the Bi2Se3 surface states are indeed preserved at the In2Se3/Bi2Se3 interface. This demonstration of an epitaxial crystalline spin-sensitive barrier that can be grown directly on Bi2Se3, and verification that it preserves the topological surface state, is electrically insulating and spin-sensitive, is an important step toward minimizing overall power consumption in SOT switching in TI/FM heterostructures in fully epitaxial topological spintronic devices.
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Affiliation(s)
- Connie H Li
- Materials Science and Technology Division, Naval Research Laboratory, Washington, DC 20375, United States
| | - Jisoo Moon
- Materials Science and Technology Division, Naval Research Laboratory, Washington, DC 20375, United States
- National Research Council, Washington, DC 20001, United States
| | - Olaf M J van 't Erve
- Materials Science and Technology Division, Naval Research Laboratory, Washington, DC 20375, United States
| | - Darshana Wickramaratne
- Materials Science and Technology Division, Naval Research Laboratory, Washington, DC 20375, United States
| | - Enrique D Cobas
- Materials Science and Technology Division, Naval Research Laboratory, Washington, DC 20375, United States
| | - Michelle D Johannes
- Materials Science and Technology Division, Naval Research Laboratory, Washington, DC 20375, United States
| | - Berend T Jonker
- Materials Science and Technology Division, Naval Research Laboratory, Washington, DC 20375, United States
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8
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Revisiting the van der Waals Epitaxy in the Case of (Bi 0.4Sb 0.6) 2Te 3 Thin Films on Dissimilar Substrates. NANOMATERIALS 2022; 12:nano12111790. [PMID: 35683648 PMCID: PMC9181916 DOI: 10.3390/nano12111790] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Revised: 05/19/2022] [Accepted: 05/20/2022] [Indexed: 11/16/2022]
Abstract
Ultrathin films of the ternary topological insulator (Bi0.4Sb0.6)2Te3 are fabricated by molecular beam epitaxy. Although it is generally assumed that the ternary topological insulator tellurides grow by van der Waals epitaxy, our results show that the influence of the substrate is substantial and governs the formation of defects, mosaicity, and twin domains. For this comparative study, InP (111)A, Al2O3 (001), and SrTiO3 (111) substrates were selected. While the films deposited on lattice-matched InP (111)A show van der Waals epitaxial relations, our results point to a quasi-van der Waals epitaxy for the films grown on substrates with a larger lattice mismatch.
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9
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Chen S, Bylinkin A, Wang Z, Schnell M, Chandan G, Li P, Nikitin AY, Law S, Hillenbrand R. Real-space nanoimaging of THz polaritons in the topological insulator Bi 2Se 3. Nat Commun 2022; 13:1374. [PMID: 35296642 PMCID: PMC8927118 DOI: 10.1038/s41467-022-28791-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Accepted: 02/09/2022] [Indexed: 12/31/2022] Open
Abstract
Plasmon polaritons in topological insulators attract attention from a fundamental perspective and for potential THz photonic applications. Although polaritons have been observed by THz far-field spectroscopy on topological insulator microstructures, real-space imaging of propagating THz polaritons has been elusive so far. Here, we show spectroscopic THz near-field images of thin Bi2Se3 layers (prototypical topological insulators) revealing polaritons with up to 12 times increased momenta as compared to photons of the same energy and decay times of about 0.48 ps, yet short propagation lengths. From the images we determine and analyze the polariton dispersion, showing that the polaritons can be explained by the coupling of THz radiation to various combinations of Dirac and massive carriers at the Bi2Se3 surfaces, massive bulk carriers and optical phonons. Our work provides critical insights into the nature of THz polaritons in topological insulators and establishes instrumentation and methodology for imaging of THz polaritons.
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Affiliation(s)
- Shu Chen
- CIC nanoGUNE BRTA, 20018, Donostia - San Sebastián, Spain
| | - Andrei Bylinkin
- CIC nanoGUNE BRTA, 20018, Donostia - San Sebastián, Spain.,Donostia International Physics Center (DIPC), 20018, Donostia - San Sebastián, Spain
| | - Zhengtianye Wang
- Department of Materials Science and Engineering, University of Delaware, Newark, Delaware, 19716, USA
| | - Martin Schnell
- CIC nanoGUNE BRTA, 20018, Donostia - San Sebastián, Spain.,IKERBASQUE, Basque Foundation for Science, 48009, Bilbao, Spain
| | - Greeshma Chandan
- Department of Materials Science and Engineering, University of Delaware, Newark, Delaware, 19716, USA
| | - Peining Li
- Wuhan National Laboratory for Optoelectronics & School of Optical and Electronic Information, Huazhong University of Science and Technology, 430074, Wuhan, China
| | - Alexey Y Nikitin
- Donostia International Physics Center (DIPC), 20018, Donostia - San Sebastián, Spain.,IKERBASQUE, Basque Foundation for Science, 48009, Bilbao, Spain
| | - Stephanie Law
- Department of Materials Science and Engineering, University of Delaware, Newark, Delaware, 19716, USA
| | - Rainer Hillenbrand
- IKERBASQUE, Basque Foundation for Science, 48009, Bilbao, Spain. .,CIC nanoGUNE BRTA and Department of Electricity and Electronics, UPV/EHU, 20018, Donostia-San Sebastián, Spain.
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10
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Ngabonziza P. Quantum transport and potential of topological states for thermoelectricity in Bi 2Te 3thin films. NANOTECHNOLOGY 2022; 33:192001. [PMID: 35081521 DOI: 10.1088/1361-6528/ac4f17] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Accepted: 01/26/2022] [Indexed: 06/14/2023]
Abstract
This paper reviews recent developments in quantum transport and it presents current efforts to explore the contribution of topological insulator boundary states to thermoelectricity in Bi2Te3thin films. Although Bi2Te3has been used as a thermoelectric material for many years, it is only recently that thin films of this material have been synthesized as 3D topological insulators with interesting physics and potential applications related to topologically protected surface states. A major bottleneck in Bi2Te3thin films has been eliminating its bulk conductivity while increasing its crystal quality. The ability to grow epitaxial films with high crystal quality and to fabricate sophisticated Bi2Te3-based devices is attractive for implementing a variety of topological quantum devices and exploring the potential of topological states to improve thermoelectric properties. Special emphasis is laid on preparing low-defect-density Bi2Te3epitaxial films, gate-tuning of normal-state transport and Josephson supercurrent in topological insulator/superconductor hybrid devices. Prospective quantum transport experiments on Bi2Te3thin-film devices are discussed as well. Finally, an overview of current progress on the contribution of topological insulator boundary states to thermoelectricity is presented. Future explorations to reveal the potential of topological states for improving thermoelectric properties of Bi2Te3films and realizing high-performance thermoelectric devices are discussed.
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Affiliation(s)
- Prosper Ngabonziza
- Max Planck Institute for Solid State Research, Heisenbergstraße 1, D-70569 Stuttgart, Germany
- Department of Physics, University of Johannesburg, PO Box 524, Auckland Park 2006, Johannesburg, South Africa
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11
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Liu J, Hesjedal T. Magnetic Topological Insulator Heterostructures: A Review. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021:e2102427. [PMID: 34665482 DOI: 10.1002/adma.202102427] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 06/05/2021] [Indexed: 06/13/2023]
Abstract
Topological insulators (TIs) provide intriguing prospects for the future of spintronics due to their large spin-orbit coupling and dissipationless, counter-propagating conduction channels in the surface state. The combination of topological properties and magnetic order can lead to new quantum states including the quantum anomalous Hall effect that was first experimentally realized in Cr-doped (Bi,Sb)2 Te3 films. Since magnetic doping can introduce detrimental effects, requiring very low operational temperatures, alternative approaches are explored. Proximity coupling to magnetically ordered systems is an obvious option, with the prospect to raise the temperature for observing the various quantum effects. Here, an overview of proximity coupling and interfacial effects in TI heterostructures is presented, which provides a versatile materials platform for tuning the magnetic and topological properties of these exciting materials. An introduction is first given to the heterostructure growth by molecular beam epitaxy and suitable structural, electronic, and magnetic characterization techniques. Going beyond transition-metal-doped and undoped TI heterostructures, examples of heterostructures are discussed, including rare-earth-doped TIs, magnetic insulators, and antiferromagnets, which lead to exotic phenomena such as skyrmions and exchange bias. Finally, an outlook on novel heterostructures such as intrinsic magnetic TIs and systems including 2D materials is given.
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Affiliation(s)
- Jieyi Liu
- Clarendon Laboratory, Department of Physics University of Oxford, Parks Road, Oxford, OX1 3PU, UK
| | - Thorsten Hesjedal
- Clarendon Laboratory, Department of Physics University of Oxford, Parks Road, Oxford, OX1 3PU, UK
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12
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Stefanou G, Menges F, Boehm B, Moran KA, Adams J, Ali M, Rosamond MC, Gotsmann B, Allenspach R, Burnell G, Hickey BJ. Scanning Thermal Microscopy and Ballistic Phonon Transport in Lateral Spin Valves. PHYSICAL REVIEW LETTERS 2021; 127:035901. [PMID: 34328759 DOI: 10.1103/physrevlett.127.035901] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Revised: 04/13/2021] [Accepted: 06/17/2021] [Indexed: 06/13/2023]
Abstract
Using scanning thermal microscopy, we have mapped the spatial distribution of temperatures in an operating nanoscale device formed from a magnetic injector, an Ag connecting wire, and a magnetic detector. An analytical model explained the thermal diffusion over the measured temperature range (2-300 K) and injector-detector separation (400-3000 nm). The characteristic diffusion lengths of the Peltier and Joule heat differ remarkably below 60 K, a fact that can be explained by the onset of ballistic phonon heat transfer in the substrate.
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Affiliation(s)
- G Stefanou
- School of Physics and Astronomy, University of Leeds, LS2 9JT Leeds, United Kingdom
| | - F Menges
- IBM Research-Zurich, Säumerstrasse 4, 8803 Rüschlikon, Switzerland
| | - B Boehm
- IBM Research-Zurich, Säumerstrasse 4, 8803 Rüschlikon, Switzerland
| | - K A Moran
- School of Physics and Astronomy, University of Leeds, LS2 9JT Leeds, United Kingdom
| | - J Adams
- School of Physics and Astronomy, University of Leeds, LS2 9JT Leeds, United Kingdom
| | - M Ali
- School of Physics and Astronomy, University of Leeds, LS2 9JT Leeds, United Kingdom
| | - M C Rosamond
- School of Electronics and Electrical Engineering, University of Leeds, LS2 9JT Leeds, United Kingdom
| | - B Gotsmann
- IBM Research-Zurich, Säumerstrasse 4, 8803 Rüschlikon, Switzerland
| | - R Allenspach
- IBM Research-Zurich, Säumerstrasse 4, 8803 Rüschlikon, Switzerland
| | - G Burnell
- IBM Research-Zurich, Säumerstrasse 4, 8803 Rüschlikon, Switzerland
| | - B J Hickey
- School of Physics and Astronomy, University of Leeds, LS2 9JT Leeds, United Kingdom
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13
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Bergeron H, Lebedev D, Hersam MC. Polymorphism in Post-Dichalcogenide Two-Dimensional Materials. Chem Rev 2021; 121:2713-2775. [PMID: 33555868 DOI: 10.1021/acs.chemrev.0c00933] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Two-dimensional (2D) materials exhibit a wide range of atomic structures, compositions, and associated versatility of properties. Furthermore, for a given composition, a variety of different crystal structures (i.e., polymorphs) can be observed. Polymorphism in 2D materials presents a fertile landscape for designing novel architectures and imparting new functionalities. The objective of this Review is to identify the polymorphs of emerging 2D materials, describe their polymorph-dependent properties, and outline methods used for polymorph control. Since traditional 2D materials (e.g., graphene, hexagonal boron nitride, and transition metal dichalcogenides) have already been studied extensively, the focus here is on polymorphism in post-dichalcogenide 2D materials including group III, IV, and V elemental 2D materials, layered group III, IV, and V metal chalcogenides, and 2D transition metal halides. In addition to providing a comprehensive survey of recent experimental and theoretical literature, this Review identifies the most promising opportunities for future research including how 2D polymorph engineering can provide a pathway to materials by design.
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Affiliation(s)
- Hadallia Bergeron
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, United States
| | - Dmitry Lebedev
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, United States
| | - Mark C Hersam
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, United States.,Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States.,Department of Electrical and Computer Engineering, Northwestern University, Evanston, Illinois 60208, United States
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14
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Lê Anh M, Potapov P, Wolf D, Lubk A, Glatz B, Fery A, Doert T, Ruck M. Freestanding Nanolayers of a Wide-Gap Topological Insulator through Liquid-Phase Exfoliation. Chemistry 2021; 27:794-801. [PMID: 33125781 PMCID: PMC7839554 DOI: 10.1002/chem.202004320] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Indexed: 11/11/2022]
Abstract
The layered salt Bi14 Rh3 I9 is a weak three-dimensional (3D) topological insulator (TI), that is, a stack of two-dimensional (2D) TIs. It has a wide non-trivial band gap of 210 meV, which is generated by strong spin-orbit coupling, and possesses protected electronic edge-states. In the structure, charged layers of∞ 2 [ (Bi4 Rh)3 I]2+ honeycombs and∞ 1 [ Bi2 I8 ]2- chains alternate. The non-trivial topology of Bi14 Rh3 I9 is an inherent property of the 2D intermetallic fragment. Here, the exfoliation of Bi14 Rh3 I9 was performed using two different chemical approaches: (a) through a reaction with n-butyllithium and poly(vinylpyrrolidone), (b) through a reaction with betaine in dimethylformamide at 55 °C. The former yielded few-layer sheets of the new compound Bi12 Rh3 I, while the latter led to crystalline sheets of Bi14 Rh3 I9 with a thickness down to 5 nm and edge-lengths up to several ten microns. X-ray diffraction and electron microscopy proved that the structure of Bi14 Rh3 I9 remained intact. Thus, it was assumed that the particles are still TIs. Dispersions of these flakes now allow for next steps towards the envisioned applications in nanoelectronics, such as the study of quantum coherence in deposited films, the combination with superconducting particles or films for the generation of Majorana fermions, or studies on their behavior under the influence of magnetic or electric fields or in contact with various materials occurring in devices. The method presented generally allows to exfoliate layers with high specific charges and thus the use of layered starting materials beyond van der Waals crystals.
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Affiliation(s)
- Mai Lê Anh
- Faculty of Chemistry and Food ChemistryTechnische Universität Dresden01062DresdenGermany
| | | | | | - Axel Lubk
- Leibniz IFW Dresden01069DresdenGermany
- Würzburg-Dresden Cluster of Excellence ct.qmatTechnische Universität Dresden01062DresdenGermany
| | - Bernhard Glatz
- Leibniz Institute of Polymer Research Dresden01069DresdenGermany
| | - Andreas Fery
- Leibniz Institute of Polymer Research Dresden01069DresdenGermany
| | - Thomas Doert
- Faculty of Chemistry and Food ChemistryTechnische Universität Dresden01062DresdenGermany
| | - Michael Ruck
- Faculty of Chemistry and Food ChemistryTechnische Universität Dresden01062DresdenGermany
- Würzburg-Dresden Cluster of Excellence ct.qmatTechnische Universität Dresden01062DresdenGermany
- Max Planck Institute for Chemical Physics of Solids01187DresdenGermany
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15
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Wei Q, Han X, Zhang H, Yang C, Zhang C, Gao J, Man B, Xu S. CVD-Bi 2Te 3 as a saturable absorber for various solitons in a mode-locked Er-doped fiber laser. APPLIED OPTICS 2020; 59:7792-7800. [PMID: 32976449 DOI: 10.1364/ao.397625] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Accepted: 07/16/2020] [Indexed: 06/11/2023]
Abstract
In this work, we report about high energy and various solitons' operation by using high-efficiency topological insulator bismuth telluride (Bi2Te3) nanofilms as broadband saturable absorbers in the passively mode-locked Er-doped fiber laser. The Bi2Te3 film was successfully synthesized by chemical vapor deposition (CVD). Excellent characteristics of the dark-bright pulse pairs, bright pulses, and multiharmonics have been investigated experimentally by adjusting the polarization state. At the same time, the maximum average output power was 40.18 mW, and the single-pulse energy was 20.91 nJ. As we all know, it is the various solitons of the first generation with large pulse energy in an Er-doped fiber laser with Bi2Te3 as saturable absorber. The experimental results show that CVD Bi2Te3 can be used as an excellent candidate in mode-locked fiber lasers.
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16
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Salvato M, Scagliotti M, De Crescenzi M, Castrucci P, De Matteis F, Crivellari M, Pelli Cresi S, Catone D, Bauch T, Lombardi F. Stoichiometric Bi 2Se 3 topological insulator ultra-thin films obtained through a new fabrication process for optoelectronic applications. NANOSCALE 2020; 12:12405-12415. [PMID: 32490504 DOI: 10.1039/d0nr02725a] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
A new fabrication process is developed for growing Bi2Se3 topological insulators in the form of nanowires/nanobelts and ultra-thin films. It consists of two consecutive procedures: first Bi2Se3 nanowires/nanobelts are deposited by standard catalyst free vapour-solid deposition on different substrates positioned inside a quartz tube. Then, the Bi2Se3, stuck on the inner surface of the quartz tube, is re-evaporated and deposited in the form of ultra-thin films on new substrates at a temperature below 100 °C, which is of relevance for flexible electronic applications. The method is new, quick, very inexpensive, easy to control and allows obtaining films with different thickness down to one quintuple layer (QL) during the same procedure. The composition and the crystal structure of both the nanowires/nanobelts and the thin films are analysed by different optical, electronic and structural techniques. For the films, scanning tunnelling spectroscopy shows that the Fermi level is positioned in the middle of the energy bandgap as a consequence of the achieved correct stoichiometry. Ultra-thin films, with thickness in the range 1-10 QLs deposited on n-doped Si substrates, show good rectifying properties suitable for their use as photodetectors in the ultra violet-visible-near infrared wavelength range.
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Affiliation(s)
- Matteo Salvato
- Dipartimento di Fisica, Università di Roma "Tor Vergata", 00133 Roma, Italy.
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17
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Rimoldi M, Cecchini R, Wiemer C, Lamperti A, Longo E, Nasi L, Lazzarini L, Mantovan R, Longo M. Epitaxial and large area Sb 2Te 3 thin films on silicon by MOCVD. RSC Adv 2020; 10:19936-19942. [PMID: 35520434 PMCID: PMC9054238 DOI: 10.1039/d0ra02567d] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Accepted: 05/18/2020] [Indexed: 11/21/2022] Open
Abstract
Antimony telluride (Sb2Te3) thin films were prepared by a room temperature Metal-Organic Chemical Vapor Deposition (MOCVD) process using antimony chloride (SbCl3) and bis(trimethylsilyl)telluride (Te(SiMe3)2) as precursors. Pre-growth and post-growth treatments were found to be pivotal in favoring out-of-plane and in-plane alignment of the crystallites composing the films. A comprehensive suite of characterization techniques were used to evaluate their composition, surface roughness, as well as to assess their morphology, crystallinity, and structural features, revealing that a quick post-growth annealing triggers the formation of epitaxial-quality Sb2Te3 films on Si(111).
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Affiliation(s)
- Martino Rimoldi
- Institute for Microelectronics and Microsystems, CNR-IMM Unit of Agrate Brianza Via C. Olivetti 2 20864 Agrate Brianza Italy
| | - Raimondo Cecchini
- Institute for Microelectronics and Microsystems, CNR-IMM Unit of Agrate Brianza Via C. Olivetti 2 20864 Agrate Brianza Italy
| | - Claudia Wiemer
- Institute for Microelectronics and Microsystems, CNR-IMM Unit of Agrate Brianza Via C. Olivetti 2 20864 Agrate Brianza Italy
| | - Alessio Lamperti
- Institute for Microelectronics and Microsystems, CNR-IMM Unit of Agrate Brianza Via C. Olivetti 2 20864 Agrate Brianza Italy
| | - Emanuele Longo
- Institute for Microelectronics and Microsystems, CNR-IMM Unit of Agrate Brianza Via C. Olivetti 2 20864 Agrate Brianza Italy .,University of Milano-Bicocca, Department of Material Science Via R. Cozzi 55 20126 Milan Italy
| | - Lucia Nasi
- Institute of Materials for Electronics and Magnetism, CNR-IMEM, Parma Parco Area delle Scienze, 7/A 43100 Parma Italy
| | - Laura Lazzarini
- Institute of Materials for Electronics and Magnetism, CNR-IMEM, Parma Parco Area delle Scienze, 7/A 43100 Parma Italy
| | - Roberto Mantovan
- Institute for Microelectronics and Microsystems, CNR-IMM Unit of Agrate Brianza Via C. Olivetti 2 20864 Agrate Brianza Italy
| | - Massimo Longo
- Institute for Microelectronics and Microsystems, CNR-IMM Unit of Agrate Brianza Via C. Olivetti 2 20864 Agrate Brianza Italy
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18
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Levy I, Youmans C, Garcia TA, Deng H, Alsheimer S, Testelin C, Krusin-Elbaum L, Ghaemi P, Tamargo MC. Designer Topological Insulator with Enhanced Gap and Suppressed Bulk Conduction in Bi 2Se 3/Sb 2Te 3 Ultrashort-Period Superlattices. NANO LETTERS 2020; 20:3420-3426. [PMID: 32315190 DOI: 10.1021/acs.nanolett.0c00338] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
A novel approach to suppress bulk conductance in three-dimensional (3D) topological insulators (TIs) using short-period superlattices (SLs) of two TIs is presented. Evidence for superlattice gap enhancement (SGE) was obtained from the reduction of bulk background doping from 1.2 × 1020 cm-3 to 8.5 × 1018 cm-3 as the period of Bi2Se3/Sb2Te3 SLs is decreased from 12 nm to 5 nm. Tight binding calculations show that, in the ultrashort-period regime, a significant SGE can be achieved for the resulting SL. Ultrathin short-period SLs behave as new designer TIs with bulk bandgaps up to 60% larger than the bandgap of the constituent layer of largest bandgap, while retaining topological surface features. Evidence for gap formation was obtained from ellipsometric measurements. Analysis of the weak antilocalization cusp in low-temperature magneto-conductance confirms that the top and bottom surfaces of the SL structure behave as Dirac surfaces. This approach represents a promising platform for building truly insulating TIs.
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Affiliation(s)
- Ido Levy
- Department of Chemistry, The City College of New York, New York, New York 10031, United States
- Chemistry Program, Graduate Center of CUNY, New York, New York 10021, United States
| | - Cody Youmans
- Department of Physics, The City College of New York, New York, New York 10031, United States
- Physics Program, Graduate Center of CUNY, New York, New York 10021, United States
| | - Thor Axtmann Garcia
- Department of Chemistry, The City College of New York, New York, New York 10031, United States
- Chemistry Program, Graduate Center of CUNY, New York, New York 10021, United States
| | - Haiming Deng
- Department of Physics, The City College of New York, New York, New York 10031, United States
- Physics Program, Graduate Center of CUNY, New York, New York 10021, United States
| | - Steven Alsheimer
- Department of Physics, The City College of New York, New York, New York 10031, United States
| | - Christophe Testelin
- Sorbonne Université, CNRS, Institut des NanoSciences de Paris, F-75005 Paris, France
| | - Lia Krusin-Elbaum
- Department of Physics, The City College of New York, New York, New York 10031, United States
- Physics Program, Graduate Center of CUNY, New York, New York 10021, United States
| | - Pouyan Ghaemi
- Department of Physics, The City College of New York, New York, New York 10031, United States
- Physics Program, Graduate Center of CUNY, New York, New York 10021, United States
| | - Maria C Tamargo
- Department of Chemistry, The City College of New York, New York, New York 10031, United States
- Chemistry Program, Graduate Center of CUNY, New York, New York 10021, United States
- Physics Program, Graduate Center of CUNY, New York, New York 10021, United States
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19
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A Novel Approach for Fabricating LaMnO 3 Thin Films Using Combined Microwave Combustion and Pulsed Electron Deposition Techniques. J CHEM-NY 2019. [DOI: 10.1155/2019/3568185] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
LaMnO3 (LMO) nanopowder was synthesized by the microwave combustion method using glycine and nitrate salts of La and Mn as precursors. The as-prepared LMO powder was pressed at high pressure and annealed at 1000°C for 8 hours to make a target for thin film deposition. The structural and elemental analysis was obtained by X-ray diffraction (XRD) and energy dispersive X-ray spectroscopy (EDS). Thin films of LMO were fabricated using pulsed electron deposition (PED) at room temperature. The effects of discharge voltage and oxygen/argon flux ratio on the produced thin films were studied. The study shows that stoichiometry and structure of the target was preserved well in the thin films prepared with a discharge voltage from 14 to 15 kV, while the oxygen/nitrogen flux ratio did not show a clear effect on the quality of thin films.
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20
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Claro MS, Levy I, Gangopadhyay A, Smith DJ, Tamargo MC. Self-assembled Bismuth Selenide (Bi 2Se 3) quantum dots grown by molecular beam epitaxy. Sci Rep 2019; 9:3370. [PMID: 30833604 PMCID: PMC6399346 DOI: 10.1038/s41598-019-39821-y] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Accepted: 01/28/2019] [Indexed: 11/25/2022] Open
Abstract
We report the growth of self-assembled Bi2Se3 quantum dots (QDs) by molecular beam epitaxy on GaAs substrates using the droplet epitaxy technique. The QD formation occurs after anneal of Bismuth droplets under Selenium flux. Characterization by atomic force microscopy, scanning electron microscopy, X-ray diffraction, high-resolution transmission electron microscopy and X-ray reflectance spectroscopy is presented. Raman spectra confirm the QD quality. The quantum dots are crystalline, with hexagonal shape, and have average dimensions of 12-nm height (12 quintuple layers) and 46-nm width, and a density of 8.5 × 109 cm−2. This droplet growth technique provides a means to produce topological insulator QDs in a reproducible and controllable way, providing convenient access to a promising quantum material with singular spin properties.
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Affiliation(s)
- Marcel S Claro
- Department of Chemistry, The City College of New York, New York, NY, 10031, USA.,INL - International Iberian Nanotechnology Laboratory, 4715-330, Braga, Portugal
| | - Ido Levy
- Department of Chemistry, The City College of New York, New York, NY, 10031, USA.,Ph.D. Program in Chemistry, The Graduate Center of the City University of New York, New York, NY, 10016, USA
| | - Abhinandan Gangopadhyay
- School for Engineering of Matter, Transport and Energy, Arizona State University, Tempe, AZ, 85287, USA
| | - David J Smith
- Department of Physics, Arizona State University, Tempe, AZ, 85287, USA
| | - Maria C Tamargo
- Department of Chemistry, The City College of New York, New York, NY, 10031, USA. .,Ph.D. Program in Chemistry, The Graduate Center of the City University of New York, New York, NY, 10016, USA.
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21
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Yang L, Xie C, Jin J, Ali RN, Feng C, Liu P, Xiang B. Properties, Preparation and Applications of Low Dimensional Transition Metal Dichalcogenides. NANOMATERIALS (BASEL, SWITZERLAND) 2018; 8:E463. [PMID: 29949877 PMCID: PMC6071048 DOI: 10.3390/nano8070463] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Revised: 06/22/2018] [Accepted: 06/22/2018] [Indexed: 11/28/2022]
Abstract
Low-dimensional layered transition metal dichalcogenides (TMDs) have recently emerged as an important fundamental research material because of their unique structural, physical and chemical properties. These novel properties make these TMDs a suitable candidate in numerous potential applications. In this review, we briefly summarize the properties of low-dimensional TMDs, and then focus on the various methods used in their preparation. The use of TMDs in electronic devices, optoelectronic devices, electrocatalysts, biosystems, and hydrogen storage is also explored. The cutting-edge future development probabilities of these materials and numerous research challenges are also outlined in this review.
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Affiliation(s)
- Lei Yang
- Key Laboratory of Biomimetic Sensor and Detecting Technology of Anhui Province, School of Materials and Chemical Engineering, West Anhui University, Lu'an 237012, China.
| | - Chenggen Xie
- Key Laboratory of Biomimetic Sensor and Detecting Technology of Anhui Province, School of Materials and Chemical Engineering, West Anhui University, Lu'an 237012, China.
| | - Juncheng Jin
- Key Laboratory of Biomimetic Sensor and Detecting Technology of Anhui Province, School of Materials and Chemical Engineering, West Anhui University, Lu'an 237012, China.
| | - Rai Nauman Ali
- Department of Materials Science & Engineering, CAS key Lab of Materials for Energy Conversion, Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei 230026, China.
| | - Chao Feng
- Department of Materials Science & Engineering, CAS key Lab of Materials for Energy Conversion, Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei 230026, China.
| | - Ping Liu
- Department of Materials Science & Engineering, CAS key Lab of Materials for Energy Conversion, Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei 230026, China.
| | - Bin Xiang
- Department of Materials Science & Engineering, CAS key Lab of Materials for Energy Conversion, Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei 230026, China.
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22
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Trivedi T, Roy A, Movva HCP, Walker ES, Bank SR, Neikirk DP, Banerjee SK. Versatile Large-Area Custom-Feature van der Waals Epitaxy of Topological Insulators. ACS NANO 2017; 11:7457-7467. [PMID: 28692797 DOI: 10.1021/acsnano.7b03894] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
As the focus of applied research in topological insulators (TI) evolves, the need to synthesize large-area TI films for practical device applications takes center stage. However, constructing scalable and adaptable processes for high-quality TI compounds remains a challenge. To this end, a versatile van der Waals epitaxy (vdWE) process for custom-feature bismuth telluro-sulfide TI growth and fabrication is presented, achieved through selective-area fluorination and modification of surface free-energy on mica. The TI features grow epitaxially in large single-crystal trigonal domains, exhibiting armchair or zigzag crystalline edges highly oriented with the underlying mica lattice and only two preferred domain orientations mirrored at 180°. As-grown feature thickness dependence on lateral dimensions and denuded zones at boundaries are observed, as explained by a semiempirical two-species surface migration model with robust estimates of growth parameters and elucidating the role of selective-area surface modification. Topological surface states contribute up to 60% of device conductance at room temperature, indicating excellent electronic quality. High-yield microfabrication and the adaptable vdWE growth mechanism with readily alterable precursor and substrate combinations lend the process versatility to realize crystalline TI synthesis in arbitrary shapes and arrays suitable for facile integration with processes ranging from rapid prototyping to scalable manufacturing.
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Affiliation(s)
- Tanuj Trivedi
- Microelectronics Research Center, Department of Electrical and Computer Engineering, The University of Texas at Austin , Austin, Texas 78758, United States
| | - Anupam Roy
- Microelectronics Research Center, Department of Electrical and Computer Engineering, The University of Texas at Austin , Austin, Texas 78758, United States
| | - Hema C P Movva
- Microelectronics Research Center, Department of Electrical and Computer Engineering, The University of Texas at Austin , Austin, Texas 78758, United States
| | - Emily S Walker
- Microelectronics Research Center, Department of Electrical and Computer Engineering, The University of Texas at Austin , Austin, Texas 78758, United States
| | - Seth R Bank
- Microelectronics Research Center, Department of Electrical and Computer Engineering, The University of Texas at Austin , Austin, Texas 78758, United States
| | - Dean P Neikirk
- Microelectronics Research Center, Department of Electrical and Computer Engineering, The University of Texas at Austin , Austin, Texas 78758, United States
| | - Sanjay K Banerjee
- Microelectronics Research Center, Department of Electrical and Computer Engineering, The University of Texas at Austin , Austin, Texas 78758, United States
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23
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Microstructure and Electrical Properties of Fe,Cu Substituted (Co,Mn)3O4 Thin Films. CRYSTALS 2017. [DOI: 10.3390/cryst7070185] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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