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Hong WK, Jang HS, Yoon J, Choi WJ. Modulation of Switching Characteristics in a Single VO 2 Nanobeam with Interfacial Strain via the Interconnection of Multiple Nanoscale Channels. ACS APPLIED MATERIALS & INTERFACES 2023; 15:11296-11303. [PMID: 36787543 DOI: 10.1021/acsami.2c21367] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
We demonstrate the modulation of electrical switching properties through the interconnection of multiple nanoscale channels (∼600 nm) in a single VO2 nanobeam with a coexisting metal-insulator (M-I) domain configuration during phase transition. The Raman scattering characteristics of the synthesized VO2 nanobeams provide evidence that substrate-induced interfacial strain can be inhomogeneously distributed along the length of the nanobeam. Interestingly, the nanoscale VO2 devices with the same channel length and width exhibit distinct differences in hysteric current-voltage characteristics, which are explained by theoretical calculations of resistance change combined with Joule heating simulations of the nanoscale VO2 channels. The observed results can be attributed to the difference in the spatial distribution and fraction ratios of M-I domains due to interfacial strain in the nanoscale VO2 channels during the metal-insulator transition process. Moreover, we demonstrate the electrically activated resistive switching characteristics based on the hysteresis behaviors of the interconnected nanoscale channels, implying the possibility of manipulating multiple resistive states. Our results may offer insights into the nanoscale engineering of correlated phases in VO2 as the key materials of neuromorphic computing for which nonlinear conductance is essential.
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Affiliation(s)
- Woong-Ki Hong
- Center for Scientific Instrumentation, Korea Basic Science Institute, Daejeon 34133, Republic of Korea
| | - Hun Soo Jang
- Chemical Materials Solutions Center, Korea Research Institute of Chemical Technology, Daejeon 34114, Republic of Korea
| | - Jongwon Yoon
- Department of Energy & Electronic Materials, Surface & Nano Materials Division, Korea Institute of Materials Science, Changwon-si, Gyeongsangnam-do 51508, Republic of Korea
| | - Woo Jin Choi
- Chemical Materials Solutions Center, Korea Research Institute of Chemical Technology, Daejeon 34114, Republic of Korea
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Lee HJ, Yang UJ, Kim KN, Park S, Kil KH, Kim JS, Wodtke AM, Choi WJ, Kim MH, Baik JM. Directional Ostwald Ripening for Producing Aligned Arrays of Nanowires. NANO LETTERS 2019; 19:4306-4313. [PMID: 31192615 DOI: 10.1021/acs.nanolett.9b00684] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The remarkable electronic and mechanical properties of nanowires have great potential for fascinating applications; however, the difficulties of assembling ordered arrays of aligned nanowires over large areas prevent their integration into many practical devices. In this paper, we show that aligned VO2 nanowires form spontaneously after heating a thin V2O5 film on a grooved SiO2 surface. Nanowires grow after complete dewetting of the film, after which there is the formation of supercooled nanodroplets and subsequent Ostwald ripening and coalescence. We investigate the growth mechanism using molecular dynamics simulations of spherical Lennard-Jones particles, and the simulations help explain how the grooved surface produces aligned nanowires. Using this simple synthesis approach, we produce self-aligned, millimeter-long nanowire arrays with uniform metal-insulator transition properties; after their transfer to a polymer substrate, the nanowires act as a highly sensitive array of strain sensors with a very fast response time of several tens of milliseconds.
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Affiliation(s)
- Hye Jin Lee
- School of Materials Science and Engineering, KIST-UNIST-Ulsan Center for Convergent Materials , Ulsan National Institute of Science and Technology (UNIST) , Ulsan 44919 , Republic of Korea
| | - U Jeong Yang
- School of Materials Science and Engineering, KIST-UNIST-Ulsan Center for Convergent Materials , Ulsan National Institute of Science and Technology (UNIST) , Ulsan 44919 , Republic of Korea
| | - Kyeong Nam Kim
- Department of Nanoengineering , University of California, San Diego (UCSD) , La Jolla , California 92093 , United States
| | - Soojin Park
- Department of Chemistry , Pohang University of Science and Technology (POSTECH) , Pohang 37673 , Republic of Korea
| | - Kye Hyoung Kil
- Department of Chemistry & Nanoscience , Ewha Womans University , Seoul 03760 , Republic of Korea
| | - Jun Soo Kim
- Department of Chemistry & Nanoscience , Ewha Womans University , Seoul 03760 , Republic of Korea
| | - Alec M Wodtke
- Department of Dynamics at Surfaces , Max Planck Institute for Biophysical Chemistry (MPI-BPC) , Göttingen 37077 , Germany
| | - Won Jun Choi
- Center for Optoelectronic Materials and Devices , Korea Institute of Science and Technology (KIST) , Seoul 02792 , Republic of Korea
| | - Myung Hwa Kim
- Department of Chemistry & Nanoscience , Ewha Womans University , Seoul 03760 , Republic of Korea
| | - Jeong Min Baik
- School of Materials Science and Engineering, KIST-UNIST-Ulsan Center for Convergent Materials , Ulsan National Institute of Science and Technology (UNIST) , Ulsan 44919 , Republic of Korea
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Thermal hysteresis measurement of the VO 2 emissivity and its application in thermal rectification. Sci Rep 2018; 8:8479. [PMID: 29855507 PMCID: PMC5981426 DOI: 10.1038/s41598-018-26687-9] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Accepted: 05/17/2018] [Indexed: 11/08/2022] Open
Abstract
Hysteresis loops in the emissivity of VO2 thin films grown on sapphire and silicon substrates by a pulsed laser deposition process are experimentally measured through the thermal-wave resonant cavity technique. Remarkable variations of about 43% are observed in the emissivity of both VO2 films, within their insulator-to-metal and metal-to-insulator transitions. It is shown that: i) The principal hysteresis width (maximum slope) in the VO2 emissivity of the VO2 + silicon sample is around 3 times higher (lower) than the corresponding one of the VO2 + sapphire sample. VO2 synthesized on silicon thus exhibits a wider principal hysteresis loop with slower MIT than VO2 on sapphire, as a result of the significant differences on the VO2 film microstructures induced by the silicon or sapphire substrates. ii) The hysteresis width along with the rate of change of the VO2 emissivity in a VO2 + substrate sample can be tuned with its secondary hysteresis loop. iii) VO2 samples can be used to build a radiative thermal diode able to operate with a rectification factor as high as 87%, when the temperature difference of its two terminals is around 17 °C. This record-breaking rectification constitutes the highest one reported in literature, for a relatively small temperature change of diode terminals.
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Jo YR, Myeong SH, Kim BJ. Role of annealing temperature on the sol–gel synthesis of VO2 nanowires with in situ characterization of their metal–insulator transition. RSC Adv 2018; 8:5158-5165. [PMID: 35542437 PMCID: PMC9078109 DOI: 10.1039/c7ra10865f] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2017] [Revised: 09/13/2018] [Accepted: 01/23/2018] [Indexed: 11/21/2022] Open
Abstract
Among the techniques to create VO2 nanostructures, the sol–gel method is the most facile and benefits from simple, manipulable synthetic parameters. Here, by utilizing various TEM techniques, we report the sequential morphological evolution of VO2 nanostructures in a sol–gel film spin-coated on a customized TEM grid, which underwent oxygen reduction as the annealing temperature increased. In situ TEM dark-field imaging and Raman spectroscopy allowed us to confirm the sharp phase transition behavior of an individual nanowire by illustrating the effect of electrode-clamping-induced tensile stress on the nucleation of the R phase from the M1 phase. The electrical transport properties of a single-nanowire device fabricated on a customized TEM grid showed excellent control of the stoichiometry and crystallinity of the wire. These results offer critical information for preparing tailored VO2 nanostructures with advanced transition properties by the sol–gel method to enable the fabrication of scalable flexible devices. The single-VO2 nanowire device synthesized via sequential morphological evolutions with oxygen reduction during annealing features a sharp metal-insulator transition.![]()
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Affiliation(s)
- Y.-R. Jo
- School of Materials Science and Engineering
- Gwangju Institute of Science and Technology (GIST)
- Gwangju
- Korea
| | - S.-H. Myeong
- School of Materials Science and Engineering
- Gwangju Institute of Science and Technology (GIST)
- Gwangju
- Korea
| | - B.-J. Kim
- School of Materials Science and Engineering
- Gwangju Institute of Science and Technology (GIST)
- Gwangju
- Korea
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Choe HS, Suh J, Ko C, Dong K, Lee S, Park J, Lee Y, Wang K, Wu J. Enhancing Modulation of Thermal Conduction in Vanadium Dioxide Thin Film by Nanostructured Nanogaps. Sci Rep 2017; 7:7131. [PMID: 28769057 PMCID: PMC5540922 DOI: 10.1038/s41598-017-07466-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Accepted: 06/23/2017] [Indexed: 11/09/2022] Open
Abstract
Efficient thermal management at the nanoscale is important for reducing energy consumption and dissipation in electronic devices, lab-on-a-chip platforms and energy harvest/conversion systems. For many of these applications, it is much desired to have a solid-state structure that reversibly switches thermal conduction with high ON/OFF ratios and at high speed. Here we describe design and implementation of a novel, all-solid-state thermal switching device by nanostructured phase transformation, i.e., modulation of contact pressure and area between two poly-silicon surfaces activated by microstructural change of a vanadium dioxide (VO2) thin film. Our solid-state devices demonstrate large and reversible alteration of cross-plane thermal conductance as a function of temperature, achieving a conductance ratio of at least 2.5. Our new approach using nanostructured phase transformation provides new opportunities for applications that require advanced temperature and heat regulations.
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Affiliation(s)
- Hwan Sung Choe
- Department of Materials Science and Engineering, University of California, Berkeley, Berkeley, CA, 94720, USA
| | - Joonki Suh
- Department of Materials Science and Engineering, University of California, Berkeley, Berkeley, CA, 94720, USA
| | - Changhyun Ko
- Department of Materials Science and Engineering, University of California, Berkeley, Berkeley, CA, 94720, USA
| | - Kaichen Dong
- Department of Materials Science and Engineering, University of California, Berkeley, Berkeley, CA, 94720, USA.,Department of Precision Instrument, Tsinghua University, Beijing, 100084, China
| | - Sangwook Lee
- Department of Materials Science and Engineering, University of California, Berkeley, Berkeley, CA, 94720, USA
| | - Joonsuk Park
- Department of Materials Science and Engineering, Stanford University, Stanford, CA, 94305, USA
| | - Yeonbae Lee
- Department of Materials Science and Engineering, University of California, Berkeley, Berkeley, CA, 94720, USA
| | - Kevin Wang
- Department of Materials Science and Engineering, University of California, Berkeley, Berkeley, CA, 94720, USA
| | - Junqiao Wu
- Department of Materials Science and Engineering, University of California, Berkeley, Berkeley, CA, 94720, USA. .,Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.
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Abbas K, Hwang J, Bae G, Choi H, Kang DJ. Control of Multilevel Resistance in Vanadium Dioxide by Electric Field Using Hybrid Dielectrics. ACS APPLIED MATERIALS & INTERFACES 2017; 9:13571-13576. [PMID: 28351132 DOI: 10.1021/acsami.6b16424] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We investigate the effect of electric field on VO2 back-gated field effect transistor (FET) devices. Using hybrid dielectric layers, we demonstrate the highest resistance modulation on the order of 102 in VO2 at a positive gate bias of 80 V (1.6 MV/cm). VO2 FET devices are prepared on SiO2 substrates of different thicknesses (100-300 nm) and hybrid dielectric layers of Al2O3/SiO2 (500 nm). For thicknesses less than 300 nm, no electric-field effects are observed, whereas for a 300 nm thickness, a small decrease in resistance is observed under a 0.2 MV/cm electric field. Under the electrostatic effect, the carrier concentration increases in VO2 devices, decreasing the resistance and the transition temperature from 66.75 to 64 °C. The leakage analysis shows that the interface quality of VO2 films on hybrid dielectric layers can be further improved. These studies suggest a multilevel fast resistance switching with the electric field and give an insight into the gate-source leakage current, which limits the phase transition in VO2 in an electric field.
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Affiliation(s)
- Kaleem Abbas
- Department of Physics and Energy Science, Sungkyunkwan University , 2066, Seobu-ro, Jangan-gu, Suwon 16419, Gyeoggi-do, Republic of Korea
| | - Jaeseok Hwang
- Department of Physics and Energy Science, Sungkyunkwan University , 2066, Seobu-ro, Jangan-gu, Suwon 16419, Gyeoggi-do, Republic of Korea
| | - Garam Bae
- Department of Physics and Energy Science, Sungkyunkwan University , 2066, Seobu-ro, Jangan-gu, Suwon 16419, Gyeoggi-do, Republic of Korea
| | - Hongsoo Choi
- Department of Robotics Engineering, Daegu Gyeongbuk Institute of Science and Technology (DGIST) , 711-873 Daegu, Republic of Korea
| | - Dae Joon Kang
- Department of Physics and Energy Science, Sungkyunkwan University , 2066, Seobu-ro, Jangan-gu, Suwon 16419, Gyeoggi-do, Republic of Korea
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Kumar S, Maury F, Bahlawane N. Electrical Switching in Semiconductor-Metal Self-Assembled VO 2 Disordered Metamaterial Coatings. Sci Rep 2016; 6:37699. [PMID: 27883052 PMCID: PMC5121613 DOI: 10.1038/srep37699] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Accepted: 11/01/2016] [Indexed: 11/21/2022] Open
Abstract
As a strongly correlated metal oxide, VO2 inspires several highly technological applications. The challenging reliable wafer-scale synthesis of high quality polycrystalline VO2 coatings is demonstrated on 4” Si taking advantage of the oxidative sintering of chemically vapor deposited VO2 films. This approach results in films with a semiconductor-metal transition (SMT) quality approaching that of the epitaxial counterpart. SMT occurs with an abrupt electrical resistivity change exceeding three orders of magnitude with a narrow hysteresis width. Spatially resolved infrared and Raman analyses evidence the self-assembly of VO2 disordered metamaterial, compresing monoclinic (M1 and M2) and rutile (R) domains, at the transition temperature region. The M2 mediation of the M1-R transition is spatially confined and related to the localized strain-stabilization of the M2 phase. The presence of the M2 phase is supposed to play a role as a minor semiconducting phase far above the SMT temperature. In terms of application, we show that the VO2 disordered self-assembly of M and R phases is highly stable and can be thermally triggered with high precision using short heating or cooling pulses with adjusted strengths. Such a control enables an accurate and tunable thermal control of the electrical switching.
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Affiliation(s)
- Sunil Kumar
- Luxembourg Institute of Science and Technology (LIST), 5 avenue des Hauts-Fourneaux L-4362 Esch-sur-Alzette Luxembourg
| | - Francis Maury
- CIRIMAT, ENSIACET-4 allée E. Monso, 31030 Toulouse, France
| | - Naoufal Bahlawane
- Luxembourg Institute of Science and Technology (LIST), 5 avenue des Hauts-Fourneaux L-4362 Esch-sur-Alzette Luxembourg
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Jo YR, Kim MW, Kim BJ. Direct correlation of structural and electrical properties of electron-doped individual VO 2 nanowires on devised TEM grids. NANOTECHNOLOGY 2016; 27:435704. [PMID: 27658734 DOI: 10.1088/0957-4484/27/43/435704] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Nano-scale VO2 wires with controlled parameters such as electron-doping have attracted intense interest due to their capability of suppressing the temperature of the metal-insulator transition (MIT). However, because their diameters are smaller than the spatial resolutions of the conventional measuring equipment, the ability to perform a thorough examination of the wires has been hindered. Here, we report the fabrication of a transmission electron microscopy (TEM) grid with an optimum design of Si3N4 windows on which the photolithography for individual electron-doped VO2 nanowire devices can be safely accomplished, allowing the cross-examination of the structural and electrical properties. TEM dark-field imaging was used to quantitatively investigate the fractions of rutile and M1 phases, and their lattice alignments were observed using high-resolution TEM (HRTEM) with small area diffraction. Moreover, electron energy loss spectroscopy (EELS) revealed that the rutile domain would be created by the strain induced by oxygen vacancies. Importantly, we successfully tuned the transition temperature by changing the rutile fraction while maintaining a high level of resistivity change. The resistivity at room temperature linearly decreased with the rutile fraction, following a simple model. Furthermore, the T dependence of the threshold voltage can be attributed to the Joule heating, exhibiting an identical thermal dependence, irrespective of the rutile fraction.
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Affiliation(s)
- Y-R Jo
- School of Materials Science and Engineering, Gwangju Institute of Science and Technology (GIST), 123 Cheomdangwagi-ro, Buk-gu, Gwangju, Korea
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Ding H, Dwaraknath SS, Garten L, Ndione P, Ginley D, Persson KA. Computational Approach for Epitaxial Polymorph Stabilization through Substrate Selection. ACS APPLIED MATERIALS & INTERFACES 2016; 8:13086-13093. [PMID: 27145398 DOI: 10.1021/acsami.6b01630] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
With the ultimate goal of finding new polymorphs through targeted synthesis conditions and techniques, we outline a computational framework to select optimal substrates for epitaxial growth using first principle calculations of formation energies, elastic strain energy, and topological information. To demonstrate the approach, we study the stabilization of metastable VO2 compounds which provides a rich chemical and structural polymorph space. We find that common polymorph statistics, lattice matching, and energy above hull considerations recommends homostructural growth on TiO2 substrates, where the VO2 brookite phase would be preferentially grown on the a-c TiO2 brookite plane while the columbite and anatase structures favor the a-b plane on the respective TiO2 phases. Overall, we find that a model which incorporates a geometric unit cell area matching between the substrate and the target film as well as the resulting strain energy density of the film provide qualitative agreement with experimental observations for the heterostructural growth of known VO2 polymorphs: rutile, A and B phases. The minimal interfacial geometry matching and estimated strain energy criteria provide several suggestions for substrates and substrate-film orientations for the heterostructural growth of the hitherto hypothetical anatase, brookite, and columbite polymorphs. These criteria serve as a preliminary guidance for the experimental efforts stabilizing new materials and/or polymorphs through epitaxy. The current screening algorithm is being integrated within the Materials Project online framework and data and hence publicly available.
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Affiliation(s)
- Hong Ding
- Energy Technologies, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States
| | - Shyam S Dwaraknath
- Energy Technologies, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States
| | - Lauren Garten
- Materials Chemistry Science and Technology, National Renewable Energy Laboratory , Golden, Colorado 80401, United States
| | - Paul Ndione
- Materials Chemistry Science and Technology, National Renewable Energy Laboratory , Golden, Colorado 80401, United States
| | - David Ginley
- Materials Chemistry Science and Technology, National Renewable Energy Laboratory , Golden, Colorado 80401, United States
| | - Kristin A Persson
- Energy Technologies, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States
- Department of Materials Science and Engineering, University of California Berkeley , Berkeley, California 94704, United States
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