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Cecchi S, Momand J, Dragoni D, Abou El Kheir O, Fagiani F, Kriegner D, Rinaldi C, Arciprete F, Holý V, Kooi BJ, Bernasconi M, Calarco R. Thick Does the Trick: Genesis of Ferroelectricity in 2D GeTe-Rich (GeTe) m (Sb 2 Te 3 ) n Lamellae. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024; 11:e2304785. [PMID: 37988708 PMCID: PMC10767439 DOI: 10.1002/advs.202304785] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Revised: 09/28/2023] [Indexed: 11/23/2023]
Abstract
The possibility to engineer (GeTe)m (Sb2 Te3 )n phase-change materials to co-host ferroelectricity is extremely attractive. The combination of these functionalities holds great technological impact, potentially enabling the design of novel multifunctional devices. Here an experimental and theoretical study of epitaxial (GeTe)m (Sb2 Te3 )n with GeTe-rich composition is presented. These layered films feature a tunable distribution of (GeTe)m (Sb2 Te3 )1 blocks of different sizes. Breakthrough evidence of ferroelectric displacement in thick (GeTe)m (Sb2 Te3 )1 lamellae is provided. The density functional theory calculations suggest the formation of a tilted (GeTe)m slab sandwiched in GeTe-rich blocks. That is, the net ferroelectric polarization is confined almost in-plane, representing an unprecedented case between 2D and bulk ferroelectric materials. The ferroelectric behavior is confirmed by piezoresponse force microscopy and electroresistive measurements. The resilience of the quasi van der Waals character of the films, regardless of their composition, is also demonstrated. Hence, the material developed hereby gathers in a unique 2D platform the phase-change and ferroelectric switching properties, paving the way for the conception of innovative device architectures.
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Affiliation(s)
- Stefano Cecchi
- Department of Materials ScienceUniversity of Milano‐Bicoccavia R. Cozzi 5520125MilanoItaly
- Paul‐Drude‐Institut für FestkörperelektronikLeibniz‐Institut im Forschungsverbund Berlin e.V.Hausvogteiplatz 5‐710117BerlinGermany
| | - Jamo Momand
- Zernike Institute for Advanced MaterialsUniversity of GroningenNijenborgh 49747 AGGroningenThe Netherlands
| | - Daniele Dragoni
- Department of Materials ScienceUniversity of Milano‐Bicoccavia R. Cozzi 5520125MilanoItaly
| | - Omar Abou El Kheir
- Department of Materials ScienceUniversity of Milano‐Bicoccavia R. Cozzi 5520125MilanoItaly
| | - Federico Fagiani
- Dipartimento di FisicaPolitecnico di MilanoP.zza Leonardo da Vinci 3220133MilanoItaly
| | - Dominik Kriegner
- Institute of Solid State and Materials PhysicsTechnische Universität DresdenHelmholtzstr. 1001069DresdenGermany
- Institute of PhysicsCzech Academy of SciencesCukrovarnická 10/11216200Praha 6Czech Republic
| | - Christian Rinaldi
- Dipartimento di FisicaPolitecnico di MilanoP.zza Leonardo da Vinci 3220133MilanoItaly
| | - Fabrizio Arciprete
- Dipartimento di FisicaUniversità di Roma “Tor Vergata”Via della Ricerca Scientifica 100133RomeItaly
| | - Vaclav Holý
- Department of Condensed Matter PhysicsFaculty of Mathematics and PhysicsCharles University, Ke Karlovu 512116PrahaCzech Republic
- Institute of Condensed Matter PhysicsFaculty of ScienceMasaryk UniversityKotlářská 2611 37BrnoCzech Republic
| | - Bart J. Kooi
- Zernike Institute for Advanced MaterialsUniversity of GroningenNijenborgh 49747 AGGroningenThe Netherlands
| | - Marco Bernasconi
- Department of Materials ScienceUniversity of Milano‐Bicoccavia R. Cozzi 5520125MilanoItaly
| | - Raffaella Calarco
- Paul‐Drude‐Institut für FestkörperelektronikLeibniz‐Institut im Forschungsverbund Berlin e.V.Hausvogteiplatz 5‐710117BerlinGermany
- CNR Institute for Microelectronics and Microsystems–IMMConsiglio Nazionale delle RicercheVia del Fosso del Cavaliere 10000133RomaItaly
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Kerres P, Zhou Y, Vaishnav H, Raghuwanshi M, Wang J, Häser M, Pohlmann M, Cheng Y, Schön CF, Jansen T, Bellin C, Bürgler DE, Jalil AR, Ringkamp C, Kowalczyk H, Schneider CM, Shukla A, Wuttig M. Scaling and Confinement in Ultrathin Chalcogenide Films as Exemplified by GeTe. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2022; 18:e2201753. [PMID: 35491494 DOI: 10.1002/smll.202201753] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2022] [Indexed: 06/14/2023]
Abstract
Chalcogenides such as GeTe, PbTe, Sb2 Te3 , and Bi2 Se3 are characterized by an unconventional combination of properties enabling a plethora of applications ranging from thermo-electrics to phase change materials, topological insulators, and photonic switches. Chalcogenides possess pronounced optical absorption, relatively low effective masses, reasonably high electron mobilities, soft bonds, large bond polarizabilities, and low thermal conductivities. These remarkable characteristics are linked to an unconventional bonding mechanism characterized by a competition between electron delocalization and electron localization. Confinement, that is, the reduction of the sample dimension as realized in thin films should alter this competition and modify chemical bonds and the resulting properties. Here, pronounced changes of optical and vibrational properties are demonstrated for crystalline films of GeTe, while amorphous films of GeTe show no similar thickness dependence. For crystalline films, this thickness dependence persists up to remarkably large thicknesses above 15 nm. X-ray diffraction and accompanying simulations employing density functional theory relate these changes to thickness dependent structural (Peierls) distortions, due to an increased electron localization between adjacent atoms upon reducing the film thickness. A thickness dependence and hence potential to modify film properties for all chalcogenide films with a similar bonding mechanism is expected.
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Affiliation(s)
- Peter Kerres
- I. Institute of Physics (IA), RWTH Aachen University, 52056, Aachen, Germany
| | - Yiming Zhou
- I. Institute of Physics (IA), RWTH Aachen University, 52056, Aachen, Germany
| | - Hetal Vaishnav
- I. Institute of Physics (IA), RWTH Aachen University, 52056, Aachen, Germany
- Peter Grünberg Institute-JARA-Institute Energy-Efficient Information Technology (PGI-10), Forschungszentrum Jülich GmbH, 52428, Jülich, Germany
| | - Mohit Raghuwanshi
- I. Institute of Physics (IA), RWTH Aachen University, 52056, Aachen, Germany
- Peter Grünberg Institute-JARA-Institute Energy-Efficient Information Technology (PGI-10), Forschungszentrum Jülich GmbH, 52428, Jülich, Germany
| | - Jiangjing Wang
- I. Institute of Physics (IA), RWTH Aachen University, 52056, Aachen, Germany
- Center for Alloy Innovation and Design, Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, 710049, China
| | - Maria Häser
- I. Institute of Physics (IA), RWTH Aachen University, 52056, Aachen, Germany
| | - Marc Pohlmann
- I. Institute of Physics (IA), RWTH Aachen University, 52056, Aachen, Germany
| | - Yudong Cheng
- I. Institute of Physics (IA), RWTH Aachen University, 52056, Aachen, Germany
- Center for Alloy Innovation and Design, Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, 710049, China
| | | | - Thomas Jansen
- Peter Grünberg Institute-Electronic Properties (PGI-6), Forschungszentrum Jülich GmbH, 52428, Jülich, Germany
| | - Christophe Bellin
- Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, Sorbonne Université, UMR CNRS 7590, MNHN, Paris, F-75005, France
| | - Daniel E Bürgler
- Peter Grünberg Institute-Electronic Properties (PGI-6), Forschungszentrum Jülich GmbH, 52428, Jülich, Germany
| | - Abdur Rehman Jalil
- Peter Grünberg Institute-Semiconductor Nanoelectronics (PGI-6), Forschungszentrum Jülich GmbH, 52428, Jülich, Germany
| | - Christoph Ringkamp
- Peter Grünberg Institute-Semiconductor Nanoelectronics (PGI-6), Forschungszentrum Jülich GmbH, 52428, Jülich, Germany
| | - Hugo Kowalczyk
- Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, Sorbonne Université, UMR CNRS 7590, MNHN, Paris, F-75005, France
| | - Claus M Schneider
- Peter Grünberg Institute-Electronic Properties (PGI-6), Forschungszentrum Jülich GmbH, 52428, Jülich, Germany
- JARA-FIT, RWTH Aachen University, 52056, Aachen, Germany
| | - Abhay Shukla
- Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, Sorbonne Université, UMR CNRS 7590, MNHN, Paris, F-75005, France
| | - Matthias Wuttig
- Peter Grünberg Institute-JARA-Institute Energy-Efficient Information Technology (PGI-10), Forschungszentrum Jülich GmbH, 52428, Jülich, Germany
- JARA-FIT, RWTH Aachen University, 52056, Aachen, Germany
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Abstract
We report the self-assembly of core–shell GeTe/Sb2Te3 nanowires (NWs) on Si (100), and SiO2/Si substrates by metalorganic chemical vapour deposition, coupled to the vapour–liquid–solid mechanism, catalyzed by Au nanoparticles. Scanning electron microscopy, X-ray diffraction, micro-Raman mapping, high-resolution transmission electron microscopy, and electron energy loss spectroscopy were employed to investigate the morphology, structure, and composition of the obtained core and core–shell NWs. A single crystalline GeTe core and a polycrystalline Sb2Te3 shell formed the NWs, having core and core–shell diameters in the range of 50–130 nm and an average length up to 7 µm.
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Zhang H, Yimam DT, de Graaf S, Momand J, Vermeulen PA, Wei Y, Noheda B, Kooi BJ. Strain Relaxation in "2D/2D and 2D/3D Systems": Highly Textured Mica/Bi 2Te 3, Sb 2Te 3/Bi 2Te 3, and Bi 2Te 3/GeTe Heterostructures. ACS NANO 2021; 15:2869-2879. [PMID: 33476130 PMCID: PMC7905873 DOI: 10.1021/acsnano.0c08842] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Strain engineering as a method to control functional properties has seen in the last decades a surge of interest. Heterostructures comprising 2D-materials and containing van der Waals(-like) gaps were considered unsuitable for strain engineering. However, recent work on heterostructures based on Bi2Te3, Sb2Te3, and GeTe showed the potential of a different type of strain engineering due to long-range mutual straining. Still, a comprehensive understanding of the strain relaxation mechanism in these telluride heterostructures is lacking due to limitations of the earlier analyses performed. Here, we present a detailed study of strain in two-dimensional (2D/2D) and mixed dimensional (2D/3D) systems derived from mica/Bi2Te3, Sb2Te3/Bi2Te3, and Bi2Te3/GeTe heterostructures, respectively. We first clearly show the fast relaxation process in the mica/Bi2Te3 system where the strain was generally transferred and confined up to the second or third van der Waals block and then abruptly relaxed. Then we show, using three independent techniques, that the long-range exponentially decaying strain in GeTe and Sb2Te3 grown on the relaxed Bi2Te3 and Bi2Te3 on relaxed Sb2Te3 as directly observed at the growth surface is still present within these three different top layers a long time after growth. The observed behavior points at immediate strain relaxation by plastic deformation without any later relaxation and rules out an elastic (energy minimization) model as was proposed recently. Our work advances the understanding of strain tuning in textured heterostructures or superlattices governed by anisotropic bonding.
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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: 40] [Impact Index Per Article: 13.3] [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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7
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Yang Z, Xu M, Cheng X, Tong H, Miao X. Manipulation of dangling bonds of interfacial states coupled in GeTe-rich GeTe/Sb 2Te 3 superlattices. Sci Rep 2017; 7:17353. [PMID: 29229978 PMCID: PMC5725461 DOI: 10.1038/s41598-017-17671-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Accepted: 11/28/2017] [Indexed: 11/09/2022] Open
Abstract
Superlattices consisting of stacked nano-sized GeTe and Sb2Te3 blocks have attracted considerable attention owing to their potential for an efficient non-melting switching mechanism, associated with complex bonding between blocks. Here, we propose possible atomic models for the superlattices, characterized by different interfacial bonding types. Based on interplanar distances extracted from ab initio calculations and electron diffraction measurements, we reveal possible intercalation of dangling bonds as the GeTe content in the superlattice increases. The dangling bonds were further confirmed by X-ray photoelectron spectroscopy, anisotropic temperature dependent resistivity measurements down to 2 K and magnetotransport analysis. Changes of partially coherent decoupled topological surfaces states upon dangling bonds varying contributed to the switching mechanism. Furthermore, the topological surface states controlled by changing the bonding between stacking blocks may be optimized for multi-functional applications.
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Affiliation(s)
- Zhe Yang
- Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, 430074, China
- School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Ming Xu
- Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, 430074, China
- School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Xiaomin Cheng
- Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, 430074, China
- School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Hao Tong
- Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, 430074, China.
- School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, 430074, China.
| | - Xiangshui Miao
- Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, 430074, China
- School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, 430074, China
- Wuhan National High Magnetic Field Centre, Huazhong University of Science and Technology, Wuhan, 430074, China
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