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Gao CS, Jian SR, Le PH, Chou WC, Juang JY, Chang HW, Lin CM. Effects of Oxygen Pressure on the Microstructures and Nanomechanical Properties of Samarium-Doped BiFeO 3 Thin Films. Micromachines (Basel) 2023; 14:1879. [PMID: 37893316 PMCID: PMC10609498 DOI: 10.3390/mi14101879] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 09/27/2023] [Accepted: 09/27/2023] [Indexed: 10/29/2023]
Abstract
In this study, samarium (Sm-10at%)-doped BiFeO3 (SmBFO) thin films were grown on platinum-coated glass substrates using pulsed laser deposition (PLD) to unveil the correlation between the microstructures and nanomechanical properties of the films. The PLD-derived SmBFO thin films were prepared under various oxygen partial pressures (PO2) of 10, 30, and 50 mTorr at a substrate temperature of 600 °C. The scanning electron microscopy analyses revealed a surface morphology consisting of densely packed grains, although the size distribution varied with the PO2. X-ray diffraction results indicate that all SmBFO thin films are textured and preferentially oriented along the (110) crystallographic orientation. The crystallite sizes of the obtained SmBFO thin films calculated from the Scherrer and (Williamson-Hall) equations increased from 20 (33) nm to 25 (52) nm with increasing PO2. In addition, the nanomechanical properties (the hardness and Young's modulus) of the SmBFO thin films were measured by using nanoindentation. The relationship between the hardness and crystalline size of SmBFO thin films appears to closely follow the Hall-Petch equation. In addition, the PO2 dependence of the film microstructure, the crystallite size, the hardness, and Young's modulus of SmBFO thin films are discussed.
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Affiliation(s)
- Chih-Sheng Gao
- Department of Materials Science and Engineering, I-Shou University, Kaohsiung City 84001, Taiwan; (C.-S.G.); (S.-R.J.)
| | - Sheng-Rui Jian
- Department of Materials Science and Engineering, I-Shou University, Kaohsiung City 84001, Taiwan; (C.-S.G.); (S.-R.J.)
- Department of Fragrance and Cosmetic Science, College of Pharmacy, Kaohsiung Medical University, Kaohsiung 80708, Taiwan
| | - Phuoc Huu Le
- Center for Plasma and Thin Film Technologies, Ming Chi University of Technology, New Taipei City 24301, Taiwan;
| | - Wu-Ching Chou
- Department of Electrophysics, National Yang Ming Chiao Tung University, Hsinchu 30010, Taiwan; (W.-C.C.); (J.-Y.J.)
| | - Jenh-Yih Juang
- Department of Electrophysics, National Yang Ming Chiao Tung University, Hsinchu 30010, Taiwan; (W.-C.C.); (J.-Y.J.)
| | - Huang-Wei Chang
- Department of Physics, National Chung Cheng University, Chia-Yi 62102, Taiwan
| | - Chih-Ming Lin
- Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan
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2
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Amrillah T, Hermawan A, Cristian YB, Oktafiani A, Dewi DMM, Amalina I, Juang JY. Potential of MXenes as a novel material for spintronic devices: a review. Phys Chem Chem Phys 2023. [PMID: 37409617 DOI: 10.1039/d3cp01261a] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/07/2023]
Abstract
The search for materials for next-generation spintronic applications has witnessed exponentially increasing interest, mainly due to the explosive development of numerous two-dimensional (2D) materials discovered in the last decade. Among them, MXenes have emerged as promising candidates for many applications due to their unique and versatile tunability in structure and properties. In particular, their excellent combination of conductivity and highly charged surfaces leads to outstanding electrochemical properties that are significant in electronic applications. Moreover, the ease of modifying the atomic and electronic structures, and thus the functionalities of MXenes, further opens up the opportunity to realize MXenes-based spintronic device applications. The explosive development of MXenes, such as tuning the bandgap and enhancing their magnetic properties, could pave the way for the integration of MXenes in device configurations suitable for spintronics. In this article, we provide an overview of the potential applications of MXenes with a special focus on spintronic device applications. We commence the discussion with various fundamental aspects of spintronics, including the understanding of materials for spintronics in general, MXenes, and their fabrication, followed by presenting perspectives on plausible strategies and future challenges in integrating MXenes into spintronic devices.
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Affiliation(s)
- Tahta Amrillah
- Nanotechnology Engineering, Faculty of Advanced Technology and Multidiscipline, Universitas Airlangga, Surabaya 60115, Indonesia.
| | - Angga Hermawan
- Research Center for Advanced Materials, National Research and Innovation Agency (BRIN), South Tangerang, Banten 15315, Indonesia
| | - Yeremia Budi Cristian
- Nanotechnology Engineering, Faculty of Advanced Technology and Multidiscipline, Universitas Airlangga, Surabaya 60115, Indonesia.
| | - Agustina Oktafiani
- Nanotechnology Engineering, Faculty of Advanced Technology and Multidiscipline, Universitas Airlangga, Surabaya 60115, Indonesia.
| | - Diva Meisya Maulina Dewi
- Nanotechnology Engineering, Faculty of Advanced Technology and Multidiscipline, Universitas Airlangga, Surabaya 60115, Indonesia.
| | - Ilma Amalina
- Nanotechnology Engineering, Faculty of Advanced Technology and Multidiscipline, Universitas Airlangga, Surabaya 60115, Indonesia.
| | - Jenh-Yih Juang
- Department of Electrophysics, National Yang Ming ChiaoTung University, Hsinchu 30010, Taiwan
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3
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Fang D, Huang S, Xu T, Sun P, Li XL, Lim YV, Yan D, Shang Y, Su BJ, Juang JY, Ge Q, Yang HY. Low-Coordinated Zn-N 2 Sites as Bidirectional Atomic Catalysis for Room-Temperature Na-S Batteries. ACS Appl Mater Interfaces 2023. [PMID: 37226049 DOI: 10.1021/acsami.3c02599] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The rational design of advanced catalysts for sodium-sulfur (Na-S) batteries is important but remains challenging due to the limited understanding of sulfur catalytic mechanisms. Here, we propose an efficient sulfur host consisting of atomic low-coordinated Zn-N2 sites dispersed on N-rich microporous graphene (Zn-N2@NG), which realizes state-of-the-art sodium-storage performance with a high sulfur content of 66 wt %, high-rate capability (467 mA h g-1 at 5 A g-1), and long cycling stability for 6500 cycles with an ultralow capacity decay rate of 0.0062% per cycle. Ex situ methods combined with theoretical calculations demonstrate the superior bidirectional catalysis of Zn-N2 sites on sulfur conversion (S8 ↔ Na2S). Furthermore, in situ transmission electron microscopy was applied to visualize the microscopic S redox evolution under the catalysis of Zn-N2 sites without liquid electrolytes. During the sodiation process, both surface S nanoparticles and S molecules in the mircopores of Zn-N2@NG quickly convert into Na2S nanograins. During the following desodiation process, only a small part of the above Na2S can be oxidized into Na2Sx. These results reveal that, without liquid electrolytes, Na2S is difficult to be decomposed even with the assistance of Zn-N2 sites. This conclusion emphasizes the critical role of liquid electrolytes in the catalytic oxidation of Na2S, which was usually ignored by previous works.
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Affiliation(s)
- Daliang Fang
- Pillar of Engineering Product Development, Singapore University of Technology and Design, 8 Somapah Road, Singapore 487372, Singapore
| | - Shaozhuan Huang
- Key Laboratory of Catalysis and Energy Materials Chemistry of Ministry of Education, South-Central University for Nationalities, Wuhan, Hubei 430074, China
| | - Tingting Xu
- Key Laboratory of Material Physics, Ministry of Education, School of Physics and Microelectronics, Zhengzhou University, Zhengzhou 450052, China
| | - Pan Sun
- NSF'S ChemMatCARS, University of Chicago, Chicago, Illinois 60637, United States
| | - Xue Liang Li
- Pillar of Engineering Product Development, Singapore University of Technology and Design, 8 Somapah Road, Singapore 487372, Singapore
| | - Yew Von Lim
- Pillar of Engineering Product Development, Singapore University of Technology and Design, 8 Somapah Road, Singapore 487372, Singapore
| | - Dong Yan
- International Joint Laboratory of New Energy Materials and Devices of Henan Province, School of Physics & Electronics, Henan University, Kaifeng 475004, China
| | - Yang Shang
- Institute of Advanced Battery Materials and Devices, Faculty of Materials and Manufacturing, Beijing University of Technology, Beijing 100124, China
| | - Bing-Jian Su
- Department of Electrophysics, National Chiao Tung University, 1001 Ta-Hsueh Road, Hsinchu 30010, Taiwan, ROC
| | - Jenh-Yih Juang
- Department of Electrophysics, National Chiao Tung University, 1001 Ta-Hsueh Road, Hsinchu 30010, Taiwan, ROC
| | - Qi Ge
- Shenzhen Key Laboratory of Biomimetic Robotics and Intelligent Systems, Department of Mechanical and Energy Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Hui Ying Yang
- Pillar of Engineering Product Development, Singapore University of Technology and Design, 8 Somapah Road, Singapore 487372, Singapore
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Amrillah T, Quynh LT, Nguyen Van C, Do TH, Arenholz E, Juang JY, Chu YH. Flexible Epsilon Iron Oxide Thin Films. ACS Appl Mater Interfaces 2021; 13:17006-17012. [PMID: 33784086 DOI: 10.1021/acsami.0c23104] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Metastable ε-Fe2O3 is a unique phase of iron oxide, which exhibits a giant coercivity field. In this work, we grew epitaxial ε-Fe2O3 films on flexible two-dimensional muscovite substrates via quasi van der Waals epitaxy. It turns out that twinning and interface energies have been playing essential roles in stabilizing metastable ε-Fe2O3 on mica substrates. Moreover, the weak interfacial bonding between ε-Fe2O3 and mica is expected to relieve the substrate clamping effect ubiquitously encountered in films epitaxially grown on rigid substrates, such as SrTiO3. It is anticipated that these flexible ε-Fe2O3 thin films can serve as a platform for exploring possible interesting emergent physical properties and eventually be integrated as flexible functional devices.
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Affiliation(s)
- Tahta Amrillah
- Department of Electrophysics, National Chiao Tung University, Hsinchu 30010, Taiwan
- Department of Nanotechnology, Faculty of Advanced Technology and Multidiscipline, Universitas Airlangga, Surabaya 60115, Indonesia
| | - Le Thi Quynh
- Department of Materials Science and Engineering, National Chiao Tung University, Hsinchu 30010, Taiwan
- Department of Physics, National Tsinghua University, Hsinchu 30013, Taiwan
| | - Chien Nguyen Van
- Department of Materials Science and Engineering, National Chiao Tung University, Hsinchu 30010, Taiwan
- Institute of Materials Sciences, Vietnam Academy of Science and Technology, Hanoi 10000, Vietnam
| | - Thi Hien Do
- Department of Materials Science and Engineering, National Chiao Tung University, Hsinchu 30010, Taiwan
| | - Elke Arenholz
- Advanced Light Source, 1 Cyclotron Road, Berkeley, California 94720, United States
| | - Jenh-Yih Juang
- Department of Electrophysics, National Chiao Tung University, Hsinchu 30010, Taiwan
| | - Ying-Hao Chu
- Department of Electrophysics, National Chiao Tung University, Hsinchu 30010, Taiwan
- Department of Materials Science and Engineering, National Chiao Tung University, Hsinchu 30010, Taiwan
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5
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Amrillah T, Hermawan A, Yin S, Juang JY. Formation and physical properties of the self-assembled BFO–CFO vertically aligned nanocomposite on a CFO-buffered two-dimensional flexible mica substrate. RSC Adv 2021; 11:15539-15545. [PMID: 35481182 PMCID: PMC9029151 DOI: 10.1039/d1ra01158h] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Accepted: 04/17/2021] [Indexed: 11/26/2022] Open
Abstract
Engineering the interfaces between materials of different structures and bonding nature in a well-controlled fashion has been playing a key role in developing new devices with unprecedented functionalities. In particular, direct growth of nanostructures on van der Waals substrates not only is essential for fully exploiting the potential of a wide variety of self-assembled nano-sized heterostructures but also can expand the horizons for electronic and photonic applications that involve nanostructures of specific composition and geometry. In the present work, we demonstrate the epitaxial growth of a self-assembled vertically aligned nanocomposite of magnetoelectric oxides on a flexible substrate via van der Waals epitaxy, which evidently adds an additional dimension of flexibility to similar thin-film heteroepitaxy architectures that have been mostly realized on rigid lattice-matched substrates. It is noted that the utilization of buffer layers is essential for obtaining high-quality flexible thin films with vertically aligned nanocomposite architecture. We believe that this route can provide alternative options for developing flexible thin-film devices with heteroepitaxy architectures of other functional materials. BiFeO3–CoFe2O4 vertically aligned nanocomposites, which mainly discovered in thin-films deposited on rigid substrates, have been successfully transformed into a flexible thin-film using a mica substrate.![]()
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Affiliation(s)
- Tahta Amrillah
- Department of Nanotechnology
- Faculty of Advanced Technology and Multidiscipline
- Universitas Airlangga
- Surabaya 60115
- Indonesia
| | - Angga Hermawan
- Institute of Multidisciplinary Research for Advanced Material (IMRAM)
- Tohoku University
- Sendai
- Japan
| | - Shu Yin
- Institute of Multidisciplinary Research for Advanced Material (IMRAM)
- Tohoku University
- Sendai
- Japan
| | - Jenh-Yih Juang
- Department of Electrophysics
- National Chiao Tung University
- Hsinchu 30010
- Taiwan
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6
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Ha TD, Chen JW, Yen M, Lai YH, Wang BY, Chin YY, Wu WB, Lin HJ, Juang JY, Chu YH. Dynamical Strain-Driven Phase Separation in Flexible CoFe 2O 4/CoO Exchange Coupling System. ACS Appl Mater Interfaces 2020; 12:46874-46882. [PMID: 32956583 DOI: 10.1021/acsami.0c11475] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Epitaxial CoFe2O4(CFO)/CoO bilayers were fabricated by pulsed laser deposition on flexible muscovite mica substrate. Samples with different CFO thicknesses were employed to study the phenomenon of exchange bias involving strongly anisotropic ferromagnet. Magnetic measurements exhibited great enhancement in the features of exchange bias. Raman and X-ray absorption spectroscopies indicated that a new phase emerged within the CFO layer because of the cation charge redistribution in CFO layer under bending, which in turn gave rise to anomalous hysteresis loops exhibited in the bent bilayers. These results provide a fundamental understanding about the mechanisms of exchange bias prevailing in these bilayers and call attention to the implementation of spintronic devices using flexible heterostructures such as the present CFO/CoO bilayers.
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Affiliation(s)
- Thai Duy Ha
- Department of Electrophyics, National Chiao Tung University, Hsinchu 30010, Taiwan
| | - Jia-Wei Chen
- Department of Materials Science and Engineering, National Chiao Tung University, Hsinchu 30010, Taiwan
| | - Min Yen
- Department of Materials Science and Engineering, National Chiao Tung University, Hsinchu 30010, Taiwan
| | - Yu-Hong Lai
- Department of Materials Science and Engineering, National Chiao Tung University, Hsinchu 30010, Taiwan
| | - Bing-Yi Wang
- Department of Physics, National Chung Cheng University, Chiayi 62102, Taiwan
| | - Yi-Ying Chin
- Department of Physics, National Chung Cheng University, Chiayi 62102, Taiwan
| | - Wen-Bin Wu
- National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan
| | - Hong-Ji Lin
- National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan
| | - Jenh-Yih Juang
- Department of Electrophyics, National Chiao Tung University, Hsinchu 30010, Taiwan
| | - Ying-Hao Chu
- Department of Electrophyics, National Chiao Tung University, Hsinchu 30010, Taiwan
- Department of Materials Science and Engineering, National Chiao Tung University, Hsinchu 30010, Taiwan
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7
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Hwang YM, Pan CT, Lu YX, Jian SR, Chang HW, Juang JY. Influence of Post-Annealing on the Structural and Nanomechanical Properties of Co Thin Films. Micromachines (Basel) 2020; 11:mi11020180. [PMID: 32050539 PMCID: PMC7074635 DOI: 10.3390/mi11020180] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Revised: 02/07/2020] [Accepted: 02/07/2020] [Indexed: 11/16/2022]
Abstract
The correlations between the microstructure and nanomechanical properties of a series of thermal annealed Co thin films were investigated. The Co thin films were deposited on glass substrates using a magnetron sputtering system at ambient conditions followed by subsequent annealing conducted at various temperatures ranging from 300 °C to 800 °C. The XRD results indicated that for annealing temperature in the ranged from 300 °C to 500 °C, the Co thin films were of single hexagonal close-packed (hcp) phase. Nevertheless, the coexistence of hcp-Co (002) and face-centered cubic (fcc-Co (111)) phases was evidently observed for films annealed at 600 °C. Further increasing the annealing temperature to 700 °C and 800 °C, the films evidently turned into fcc-Co (111). Moreover, significant variations in the hardness and Young’s modulus are observed by continuous stiffness nanoindentation measurement for films annealed at different temperatures. The correlations between structures and properties are discussed.
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Affiliation(s)
- Yeong-Maw Hwang
- Department of Mechanical and Electro-Mechanical Engineering, National Sun Yat-Sen University, Kaohsiung 804, Taiwan; (Y.-M.H.); (C.-T.P.); (Y.-X.L.)
| | - Cheng-Tang Pan
- Department of Mechanical and Electro-Mechanical Engineering, National Sun Yat-Sen University, Kaohsiung 804, Taiwan; (Y.-M.H.); (C.-T.P.); (Y.-X.L.)
| | - Ying-Xu Lu
- Department of Mechanical and Electro-Mechanical Engineering, National Sun Yat-Sen University, Kaohsiung 804, Taiwan; (Y.-M.H.); (C.-T.P.); (Y.-X.L.)
| | - Sheng-Rui Jian
- Department of Materials Science and Engineering, I-Shou University, Kaohsiung 840, Taiwan
- Correspondence: (S.-R.J.); (H.-W.C.); Tel.: +886-7-657-7711-3130 (S.-R.J.)
| | - Huang-Wei Chang
- Department of Physics, National Chung Cheng University, Chia-Yi 621, Taiwan
- Correspondence: (S.-R.J.); (H.-W.C.); Tel.: +886-7-657-7711-3130 (S.-R.J.)
| | - Jenh-Yih Juang
- Department of Electrophysics, National Chiao Tung University, Hsinchu 300, Taiwan;
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Ha TD, Yen M, Lai YH, Kuo CY, Chen CT, Tanaka A, Tsai LZ, Zhao YF, Duan CG, Lee SF, Chang CF, Juang JY, Chu YH. Mechanically tunable exchange coupling of Co/CoO bilayers on flexible muscovite substrates. Nanoscale 2020; 12:3284-3291. [PMID: 31971196 DOI: 10.1039/c9nr08810e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The employment of flexible muscovite substrates has given us the feasibility of applying strain to heterostructures dynamically by mechanical bending. In this study, this novel approach is utilized to investigate strain effects on the exchange coupling in ferromagnetic Co and anti-ferromagnetic CoO (Co/CoO) bilayers. Two different Co/CoO bilayer heterostructures were grown on muscovite substrates by oxide molecular beam epitaxy, with the CoO layer being purely (111)- and (100)-oriented. The strain-dependent exchange coupling effect can only be observed on Co/CoO(100)/mica but not on Co/CoO(111)/mica. The origin of this phenomenon is attributed to the anisotropic spin re-orientation induced by mechanical bending. The strain-dependent magnetic anisotropy of the bilayers determined by anisotropic magnetoresistance measurements confirms this conjecture. This study elucidates the fundamental understanding of how magnetic exchange coupling can be tuned by externally applied strain via mechanical bending and, hence, provides a novel approach for implementing flexible spintronic devices.
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Affiliation(s)
- Thai Duy Ha
- Department of Electrophysics, National Chiao Tung University, Hsinchu 30010, Taiwan. and Max-Planck Institute for Chemical Physics of Solids, Nöthnitzer Strasse 40, Dresden 01187, Germany
| | - Min Yen
- Department of Materials Science and Engineering, National Chiao Tung University, Hsinchu 30010, Taiwan
| | - Yu-Hong Lai
- Department of Materials Science and Engineering, National Chiao Tung University, Hsinchu 30010, Taiwan
| | - Chang-Yang Kuo
- Max-Planck Institute for Chemical Physics of Solids, Nöthnitzer Strasse 40, Dresden 01187, Germany and National Synchrotron Radiation Research Center, Hsinchu, 30076, Taiwan
| | - Chien-Te Chen
- National Synchrotron Radiation Research Center, Hsinchu, 30076, Taiwan
| | - Arata Tanaka
- Department of Quantum Matter, ADSM, Hiroshima University, Higashi-Hiroshima 739-8530, Japan
| | - Li-Zai Tsai
- Insitute of Physics, Academia Sinica, Taipei 11529, Taiwan
| | - Yi-Feng Zhao
- Department of Electronic Engineering, East China Normal University, Shanghai, China
| | - Chun-Gang Duan
- Department of Electronic Engineering, East China Normal University, Shanghai, China
| | - Shang-Fan Lee
- Insitute of Physics, Academia Sinica, Taipei 11529, Taiwan
| | - Chun-Fu Chang
- Max-Planck Institute for Chemical Physics of Solids, Nöthnitzer Strasse 40, Dresden 01187, Germany
| | - Jenh-Yih Juang
- Department of Electrophysics, National Chiao Tung University, Hsinchu 30010, Taiwan.
| | - Ying-Hao Chu
- Department of Electrophysics, National Chiao Tung University, Hsinchu 30010, Taiwan. and Department of Materials Science and Engineering, National Chiao Tung University, Hsinchu 30010, Taiwan and Insitute of Physics, Academia Sinica, Taipei 11529, Taiwan
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9
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Amrillah T, Chen YX, Duong MN, Abdussalam W, Simanjuntak FM, Chen CH, Chu YH, Juang JY. Effects of pillar size modulation on the magneto-structural coupling in self-assembled BiFeO3–CoFe2O4 heteroepitaxy. CrystEngComm 2020. [DOI: 10.1039/c9ce01573f] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The magneto-structural coupling of BiFeO3 (BFO)–CoFe2O4 (CFO)/LaAlO3 (LAO) heteroepitaxy with various lateral sizes of CFO pillars embedded in a BFO matrix was investigated.
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Affiliation(s)
- Tahta Amrillah
- Department of Physics
- Faculty of Science and Technology
- Airlangga University
- Surabaya 60115
- Indonesia
| | - Yu-Xun Chen
- Department of Electrophysics
- National Chiao Tung University
- Hsinchu 30010
- Taiwan
- National Synchrotron Radiation Research Center (NSRRC)
| | - My Ngoc Duong
- Department of Electrophysics
- National Chiao Tung University
- Hsinchu 30010
- Taiwan
| | | | | | - Chia-Hao Chen
- National Synchrotron Radiation Research Center (NSRRC)
- Hsinchu
- Taiwan
| | - Ying-Hao Chu
- Department of Electrophysics
- National Chiao Tung University
- Hsinchu 30010
- Taiwan
- Department of Materials Science and Engineering
| | - Jenh-Yih Juang
- Department of Electrophysics
- National Chiao Tung University
- Hsinchu 30010
- Taiwan
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10
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Chiu YJ, Jian SR, Liu TJ, Le PH, Juang JY. Localized Deformation and Fracture Behaviors in InP Single Crystals by Indentation. Micromachines (Basel) 2018; 9:mi9120611. [PMID: 30469471 PMCID: PMC6315416 DOI: 10.3390/mi9120611] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Revised: 11/14/2018] [Accepted: 11/18/2018] [Indexed: 12/03/2022]
Abstract
The indentation-induced deformation mechanisms in InP(100) single crystals were investigated by using nanoindentation and cross-sectional transmission electron microscopy (XTEM) techniques. The results indicated that there were multiple “pop-in” events randomly distributed in the loading curves, which were conceived to arise primarily from the dislocation nucleation and propagation activities. An energetic estimation on the number of nanoindentation-induced dislocations associated with pop-in effects is discussed. Furthermore, the fracture patterns were performed by Vickers indentation. The fracture toughness and the fracture energy of InP(100) single crystals were calculated to be around 1.2 MPa·m1/2 and 14.1 J/m2, respectively.
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Affiliation(s)
- Yi-Jui Chiu
- School of Mechanical and Automotive Engineering, Xiamen University of Technology, No.600 Ligong Road, Jimei District, Xiamen 361024, China.
| | - Sheng-Rui Jian
- Department of Materials Science and Engineering, I-Shou University, Kaohsiung 840, Taiwan.
| | - Ti-Ju Liu
- Department of Materials Science and Engineering, I-Shou University, Kaohsiung 840, Taiwan.
| | - Phuoc Huu Le
- Department of Physics and Biophysics, Faculty of Basic Sciences, Can Tho University of Medicine and Pharmacy, 179 Nguyen Van Cu Street, Can Tho 94000, Vietnam.
| | - Jenh-Yih Juang
- Department of Electrophysics, National Chiao Tung University, Hsinchu 300, Taiwan.
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11
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Durán Retamal JR, Kang CF, Lien DH, Kuo WC, Juang ZY, Tsai ML, Ho CH, Juang JY, Hsiao VKS, Chu YH, Li LJ, Wu Y, He JH. A Nanostructuring Method to Decouple Electrical and Thermal Transport through the Formation of Electrically Triggered Conductive Nanofilaments. Adv Mater 2018; 30:e1705385. [PMID: 29806141 DOI: 10.1002/adma.201705385] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Indexed: 05/25/2023]
Abstract
Transforming thermal energy into electric energy and vice versa needs the decoupling of electrical transport from thermal transport. An innovative strategy is proposed by forming/disrupting electrically triggered conductive nanofilaments within semiconducting thin films to switch thermoelectric properties between two states without further material modification and manufacturing processes. It can also controllably adjust the degree of decoupling, providing a potential resolution and performance adjustability for heat/coldness control or power consumption reduction on demand.
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Affiliation(s)
- José Ramón Durán Retamal
- Computer, Electrical and Mathematical Sciences and Engineering (CEMSE) Division, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Kingdom of Saudi Arabia
| | - Chen-Fang Kang
- Computer, Electrical and Mathematical Sciences and Engineering (CEMSE) Division, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Kingdom of Saudi Arabia
| | - Der-Hsien Lien
- Computer, Electrical and Mathematical Sciences and Engineering (CEMSE) Division, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Kingdom of Saudi Arabia
| | - Wei-Cheng Kuo
- Department of Electrophysics, National Chiao Tung University, Hsinchu, 30010, Taiwan, Republic of China
- Department of Materials Science and Engineering, National Chiao Tung University, Hsinchu, 30010, Taiwan, Republic of China
| | - Zhen-Yu Juang
- Physical Sciences and Engineering (PSE) Division, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Kingdom of Saudi Arabia
| | - Meng-Lin Tsai
- Computer, Electrical and Mathematical Sciences and Engineering (CEMSE) Division, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Kingdom of Saudi Arabia
| | - Chih-Hsiang Ho
- Department of Electrical and Computer Engineering, Purdue University, West Lafayette, IN, 47907, USA
| | - Jenh-Yih Juang
- Department of Electrophysics, National Chiao Tung University, Hsinchu, 30010, Taiwan, Republic of China
| | - Vincent K S Hsiao
- Computer, Electrical and Mathematical Sciences and Engineering (CEMSE) Division, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Kingdom of Saudi Arabia
| | - Ying-Hao Chu
- Department of Materials Science and Engineering, National Chiao Tung University, Hsinchu, 30010, Taiwan, Republic of China
| | - Lain-Jong Li
- Physical Sciences and Engineering (PSE) Division, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Kingdom of Saudi Arabia
| | - Yue Wu
- Department of Chemical and Biological Engineering, Iowa State University, Ames, IA, 50011, USA
| | - Jr-Hau He
- Computer, Electrical and Mathematical Sciences and Engineering (CEMSE) Division, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Kingdom of Saudi Arabia
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12
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Lin CM, Hsu IJ, Lin SC, Chuang YC, Chen WT, Liao YF, Juang JY. Pressure effect on impurity local vibrational mode and phase transitions in n-type iron-doped indium phosphide. Sci Rep 2018; 8:1284. [PMID: 29352141 PMCID: PMC5775340 DOI: 10.1038/s41598-018-19679-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Accepted: 01/02/2018] [Indexed: 11/09/2022] Open
Abstract
The evolution of iron local vibrational mode (Fe LVM) and phase transitions in n-type iron-doped indium phosphide (InP:Fe) were investigated at ambient temperature. In-situ angle-dispersive X-ray diffraction measurements revealed that InP:Fe starts to transform from zinc-blende (ZB) to rock-salt (RS) structure around 8.2(2) GPa and completes around 16.0(2) GPa. The Raman shift of both transverse and longitudinal optical modes increases monotonically with increasing pressure, while their intensities become indiscernible at 11.6(2) GPa, suggesting that the pressure-induced phase transition is accompanied by significant metallization. In contrast, originally absent at ambient pressure, the Raman shift of Fe LVM appears at ∼420 cm-1 near 1.2 GPa and exhibits a dome shape behavior with increasing pressure, reaching a maximum value of ∼440 cm-1 around 5 GPa, with an apparent kink occurring around the ZB-RS transition pressure of ∼8.5(2) GPa. The Fe K-edge X-ray absorption near edge structure (XANES) confirmed the tetrahedral site occupation of Fe3+ with a crystal field splitting parameter Δ t = 38 kJ·mole-1. Our calculations indicate that the energy parameters governing the phase transition are Δt = 0.49 and Δ o = 1.10 kJ·mole-1, respectively, both are much smaller than Δ t = 38 kJ·mole-1 at ambient.
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Affiliation(s)
- Chih-Ming Lin
- Department of Physics, National Tsing Hua University, Hsinchu, 30013, Taiwan.
| | - I-Jui Hsu
- Department of Molecular Science and Engineering, National Taipei University of Technology, Taipei, 10608, Taiwan.
| | - Sin-Cheng Lin
- Department of Physics, National Tsing Hua University, Hsinchu, 30013, Taiwan
| | - Yu-Chun Chuang
- National Synchrotron Radiation Research Center, Hsinchu, 30076, Taiwan
| | - Wei-Ting Chen
- Department of Molecular Science and Engineering, National Taipei University of Technology, Taipei, 10608, Taiwan
| | - Yen-Fa Liao
- National Synchrotron Radiation Research Center, Hsinchu, 30076, Taiwan
| | - Jenh-Yih Juang
- Department of Electrophysics, National Chiao Tung University, Hsinchu, 30050, Taiwan.
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13
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Chen SC, Wang SW, Kuo SY, Juang JY, Lee PT, Luo CW, Wu KH, Kuo HC. A Comprehensive Study of One-Step Selenization Process for Cu(In 1-x Ga x )Se 2 Thin Film Solar Cells. Nanoscale Res Lett 2017; 12:208. [PMID: 28330186 PMCID: PMC5360741 DOI: 10.1186/s11671-017-1993-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Accepted: 03/12/2017] [Indexed: 06/06/2023]
Abstract
In this work, aiming at developing a rapid and environmental-friendly process for fabricating CuIn1-x Ga x Se2 (CIGS) solar cells, we demonstrated the one-step selenization process by using selenium vapor as the atmospheric gas instead of the commonly used H2Se gas. The photoluminescence (PL) characteristics indicate that there exists an optimal location with superior crystalline quality in the CIGS thin films obtained by one-step selenization. The energy dispersive spectroscopy (EDS) reveals that the Ga lateral distribution in the one-step selenized CIGS thin film is intimately correlated to the blue-shifted PL spectra. The surface morphologies examined by scanning electron microscope (SEM) further suggested that voids and binary phase commonly existing in CIGS films could be successfully eliminated by the present one-step selenization process. The agglomeration phenomenon attributable to the formation of MoSe2 layer was also observed. Due to the significant microstructural improvement, the current-voltage (J-V) characteristics and external quantum efficiency (EQE) of the devices made of the present CIGS films have exhibited the remarkable carrier transportation characteristics and photon utilization at the optimal location, resulting in a high conversion efficiency of 11.28%. Correlations between the defect states and device performance of the one-step selenized CIGS thin film were convincingly delineated by femtosecond pump-probe spectroscopy.
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Affiliation(s)
- Shih-Chen Chen
- Department of Electrophysics, National Chiao-Tung University, Hsinchu, Taiwan
| | - Sheng-Wen Wang
- Department of Photonics and Institute of Electro-Optical Engineering, National Chiao-Tung University, Hsinchu, Taiwan
| | - Shou-Yi Kuo
- Department of Electronic Engineering, Chang Gung University, Taoyuan, Taiwan
- Department of Nuclear Medicine, Chang Gung Memorial Hospital, Taoyuan, Taiwan
| | - Jenh-Yih Juang
- Department of Electrophysics, National Chiao-Tung University, Hsinchu, Taiwan
| | - Po-Tsung Lee
- Department of Photonics and Institute of Electro-Optical Engineering, National Chiao-Tung University, Hsinchu, Taiwan
| | - Chih Wei Luo
- Department of Electrophysics, National Chiao-Tung University, Hsinchu, Taiwan
| | - Kaung-Hsiung Wu
- Department of Electrophysics, National Chiao-Tung University, Hsinchu, Taiwan
| | - Hao-Chung Kuo
- Department of Photonics and Institute of Electro-Optical Engineering, National Chiao-Tung University, Hsinchu, Taiwan
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Amrillah T, Bitla Y, Shin K, Yang T, Hsieh YH, Chiou YY, Liu HJ, Do TH, Su D, Chen YC, Jen SU, Chen LQ, Kim KH, Juang JY, Chu YH. Flexible Multiferroic Bulk Heterojunction with Giant Magnetoelectric Coupling via van der Waals Epitaxy. ACS Nano 2017; 11:6122-6130. [PMID: 28531355 DOI: 10.1021/acsnano.7b02102] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Magnetoelectric nanocomposites have been a topic of intense research due to their profound potential in the applications of electronic devices based on spintronic technology. Nevertheless, in spite of significant progress made in the growth of high-quality nanocomposite thin films, the substrate clamping effect still remains a major hurdle in realizing the ultimate magnetoelectric coupling. To overcome this obstacle, an alternative strategy of fabricating a self-assembled ferroelectric-ferrimagnetic bulk heterojunction on a flexible muscovite via van der Waals epitaxy is adopted. In this study, we investigated the magnetoelectric coupling in a self-assembled BiFeO3 (BFO)-CoFe2O4 (CFO) bulk heterojunction epitaxially grown on a flexible muscovite substrate. The obtained heterojunction is composed of vertically aligned multiferroic BFO nanopillars embedded in a ferrimagnetic CFO matrix. Moreover, due to the weak interaction between the flexible substrate and bulk heterojunction, the interface is incoherent and, hence, the substrate clamping effect is greatly reduced. The phase-field simulation model also complements our results. The magnetic and electrical characterizations highlight the improvement in magnetoelectric coupling of the BFO-CFO bulk heterojunction. A magnetoelectric coupling coefficient of 74 mV/cm·Oe of this bulk heterojunction is larger than the magnetoelectric coefficient reported earlier on flexible substrates. Therefore, this study delivers a viable route of fabricating a remarkable magnetoelectric heterojunction and yet flexible electronic devices that are robust against extreme conditions with optimized performance.
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Affiliation(s)
| | | | - Kwangwoo Shin
- CeNSCMR, Department of Physics and Astronomy, Seoul National University , Seoul 151-747, Republic of Korea
| | - Tiannan Yang
- Department of Materials Science and Engineering, Pennsylvania State University , University Park, Pennsylvania 16802, United States
| | | | - Yu-You Chiou
- Department of Physics, National Cheng Kung University , Tainan 70101, Taiwan
| | - Heng-Jui Liu
- Department of Materials Science and Engineering, National Chung Hsing University , Taichung 40227, Taiwan
| | - Thi Hien Do
- Institute of Physics, Academia Sinica , Taipei 11529, Taiwan
| | - Dong Su
- Center for Functional Nanomaterials, Brookhaven National Laboratory , Upton, New York 11973, United States
| | - Yi-Chun Chen
- Department of Physics, National Cheng Kung University , Tainan 70101, Taiwan
| | - Shien-Uang Jen
- Institute of Physics, Academia Sinica , Taipei 11529, Taiwan
| | - Long-Qing Chen
- Department of Materials Science and Engineering, Pennsylvania State University , University Park, Pennsylvania 16802, United States
| | - Kee Hoon Kim
- CeNSCMR, Department of Physics and Astronomy, Seoul National University , Seoul 151-747, Republic of Korea
| | | | - Ying-Hao Chu
- Institute of Physics, Academia Sinica , Taipei 11529, Taiwan
- Material and Chemical Research Laboratories, Industrial Technology Research Institute , Hsinchu 31040, Taiwan
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15
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Chen SC, She NZ, Wu KH, Chen YZ, Lin WS, Li JX, Lai FI, Juang JY, Luo CW, Cheng LT, Hsieh TP, Kuo HC, Chueh YL. Crystalline Engineering Toward Large-Scale High-Efficiency Printable Cu(In,Ga)Se 2 Thin Film Solar Cells on Flexible Substrate by Femtosecond Laser Annealing Process. ACS Appl Mater Interfaces 2017; 9:14006-14012. [PMID: 28281352 DOI: 10.1021/acsami.7b00082] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Ink-printing method emerges as a viable way for manufacturing large-scale flexible Cu(In,Ga)Se2 (CIGS) thin film photovoltaic (TFPV) devices owing to its potential for the rapid process, mass production, and low-cost nonvacuum device fabrication. Here, we brought the femtosecond laser annealing (fs-LA) process into the ink-printing CIGS thin film preparation. The effects of fs-LA treatment on the structural and optoelectronic properties of the ink-printing CIGS thin films were systematically investigated. It was observed that, while the film surface morphology remained essentially unchanged under superheating, the quality of crystallinity was significantly enhanced after the fs-LA treatment. Moreover, a better stoichiometric composition was achieved with an optimized laser scanning rate of the laser beam, presumably due to the much reduced indium segregation phenomena, which is believed to be beneficial in decreasing the defect states of InSe, VSe, and InCu. Consequently, the shunt leakage current and recombination centers were both greatly decreased, resulting in a near 20% enhancement in photovoltaic conversion efficiency.
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Affiliation(s)
| | | | | | - Yu-Ze Chen
- Department of Materials Science and Engineering, National Tsing Hua University , Hsinchu 30013, Taiwan, ROC
| | - Wei-Sheng Lin
- Compound Semiconductor Solar Cell Department, Next Generation Solar Cell Division, Green Energy and Environment Research Laboratories, Industrial Technology Research Institute , Hsinchu 31040, Taiwan, ROC
| | | | - Fang-I Lai
- Department of Photonics Engineering, Yuan-Ze University , Taoyuan 32003, Taiwan, ROC
| | | | | | - Lung-Teng Cheng
- Compound Semiconductor Solar Cell Department, Next Generation Solar Cell Division, Green Energy and Environment Research Laboratories, Industrial Technology Research Institute , Hsinchu 31040, Taiwan, ROC
| | - Tung-Po Hsieh
- Compound Semiconductor Solar Cell Department, Next Generation Solar Cell Division, Green Energy and Environment Research Laboratories, Industrial Technology Research Institute , Hsinchu 31040, Taiwan, ROC
| | | | - Yu-Lun Chueh
- Department of Materials Science and Engineering, National Tsing Hua University , Hsinchu 30013, Taiwan, ROC
- School of Material Science and Engineering, State Key Laboratory of Advanced Processing and Recycling of Non-Ferrous Metals, Lanzhou University of Technology , Lanzhou City 730050, Gansu Province, P. R. China
- Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China , Chengdu 611731, P. R. China
- Department of Physics, National Sun Yat-Sen University , Kaohsiung, 80424, Taiwan, ROC
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16
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Chang YM, Lin ML, Lai TY, Chen CH, Lee HY, Lin CM, Wu YCS, Lin YF, Juang JY. Broadband Omnidirectional Light Trapping in Gold-Decorated ZnO Nanopillar Arrays. ACS Appl Mater Interfaces 2017; 9:11985-11992. [PMID: 28301136 DOI: 10.1021/acsami.6b16412] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The photoluminescence (PL) and reflectivity characteristics of zinc oxide nanopillars (ZnO-NPs) grown on indium-tin-oxide (ITO)-coated glasses were investigated. The room temperature PL showed bright white-light emission for the undoped ZnO-NPs grown at 600 °C, suggesting the close relation between the optical characteristic and the growth conditions being carried out for obtaining the present ZnO-NPs. The reflectivity of the as-grown ZnO-NPs array was about ∼29% with the wavelength of the incident light ranging from 200 to 1800 nm. Nevertheless, the reflectance reduced significantly to less than 9.9% when a layer of gold (Au) was deposited on ZnO-NPs by sputtering for 5 min, corresponding to more than 65% reduction in Au-coated ZnO-NPs (Au/ZnO-NPs). Moreover, the angle-resolved reflectance measurements on the present Au/ZnO-NPs array show an omnidirectional light-trapping characteristic. These remarkable characteristics, broadband and omnidirectional light-trapping of Au/ZnO-NPs, are attributed to the extended effective optical path of the incident light due to subwavelength scattering resulting from the presence of Au nanoparticles.
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Affiliation(s)
- Yuan-Ming Chang
- Department of Physics, National Chung Hsing University , Taichung 402, Taiwan
| | - Man-Ling Lin
- Department of Electrophysics, National Chiao Tung University , Hsinchu 300, Taiwan
| | - Tung-Yen Lai
- Department of Materials and Engineering, National Chiao Tung University , Hsinchu 300, Taiwan
| | - Chang-Hung Chen
- Department of Physics, National Chung Hsing University , Taichung 402, Taiwan
| | - Hsin-Yi Lee
- Department of Materials and Engineering, National Chiao Tung University , Hsinchu 300, Taiwan
- National Synchrotron Radiation Research Center , Hsinchu 300, Taiwan
| | - Chih-Ming Lin
- Department of Physics, National Tsing Hua University , Hsinchu 300, Taiwan
| | - Yew-Chung Sermon Wu
- Department of Materials and Engineering, National Chiao Tung University , Hsinchu 300, Taiwan
| | - Yen-Fu Lin
- Department of Physics, National Chung Hsing University , Taichung 402, Taiwan
| | - Jenh-Yih Juang
- Department of Electrophysics, National Chiao Tung University , Hsinchu 300, Taiwan
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17
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Liu HJ, Wang CK, Su D, Amrillah T, Hsieh YH, Wu KH, Chen YC, Juang JY, Eng LM, Jen SU, Chu YH. Flexible Heteroepitaxy of CoFe 2O 4/Muscovite Bimorph with Large Magnetostriction. ACS Appl Mater Interfaces 2017; 9:7297-7304. [PMID: 28155267 DOI: 10.1021/acsami.6b16485] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
A bimorph composed of ferrimagnetic cobalt ferrite (CoFe2O4, CFO) and flexible muscovite was fabricated via van der Waals epitaxy. The combination of X-ray diffraction and transmission electron microscopy was conducted to reveal the heteroepitaxy of the CFO/muscovite system. The robust magnetic behaviors against mechanical bending were characterized by hysteresis measurements and magnetic force microscopy, which maintain a saturation magnetization (Ms) of ∼120-150 emu/cm3 under different bending states. The large magnetostrictive response of the CFO film was then determined by digital holographic microscopy, where the difference of magnetostrction coefficient (Δλ) is -104 ppm. The superior performance of this bimorph is attributed to the nature of weak interaction between film and substrate. Such a flexible CFO/muscovite bimorph provides a new platform to develop next-generation flexible magnetic devices.
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Affiliation(s)
- Heng-Jui Liu
- Department of Materials Science and Engineering, National Chung Hsing University , Taichung 40227, Taiwan
| | - Chih-Kuo Wang
- Department of Materials Science and Engineering, National Chiao Tung University , Hsinchu 30010, Taiwan
| | - Dong Su
- Center for Functional Nanomaterials, Brookhaven National Laboratory , Upton, New York 11973, United States
| | - Tahta Amrillah
- Department of Electrophysics, National Chiao Tung University , Hsinchu 30010, Taiwan
| | - Ying-Hui Hsieh
- Department of Materials Science and Engineering, National Chung Hsing University , Taichung 40227, Taiwan
- Institut für Angewandte Photophysik, Technische Universitat Dresden , Dresden 01069, Germany
| | - Kun-Hong Wu
- Department of Physics, National Cheng Kung University , Tainan 701, Taiwan
| | - Yi-Chun Chen
- Department of Physics, National Cheng Kung University , Tainan 701, Taiwan
| | - Jenh-Yih Juang
- Department of Electrophysics, National Chiao Tung University , Hsinchu 30010, Taiwan
| | - Lukas M Eng
- Institut für Angewandte Photophysik, Technische Universitat Dresden , Dresden 01069, Germany
| | - Shien-Uang Jen
- Institute of Physics, Academia Sinica , Taipei 11529, Taiwan
- Institute of Optoelectronic Science, National Taiwan Ocean University , Keelung 20224, Taiwan
| | - Ying-Hao Chu
- Department of Materials Science and Engineering, National Chiao Tung University , Hsinchu 30010, Taiwan
- Department of Electrophysics, National Chiao Tung University , Hsinchu 30010, Taiwan
- Institute of Physics, Academia Sinica , Taipei 11529, Taiwan
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18
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Dimitrov D, Rafailov P, Marinova V, Babeva T, Goovaerts E, Chen YF, Lee CS, Juang JY. Structural and optical properties of LuVO4 single crystals. ACTA ACUST UNITED AC 2017. [DOI: 10.1088/1742-6596/794/1/012029] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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19
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Wu PC, Chen PF, Do TH, Hsieh YH, Ma CH, Ha TD, Wu KH, Wang YJ, Li HB, Chen YC, Juang JY, Yu P, Eng LM, Chang CF, Chiu PW, Tjeng LH, Chu YH. Heteroepitaxy of Fe 3O 4/Muscovite: A New Perspective for Flexible Spintronics. ACS Appl Mater Interfaces 2016; 8:33794-33801. [PMID: 27960370 DOI: 10.1021/acsami.6b11610] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Spintronics has captured a lot of attention since it was proposed. It has been triggering numerous research groups to make their efforts on pursuing spin-related electronic devices. Recently, flexible and wearable devices are in a high demand due to their outstanding potential in practical applications. In order to introduce spintronics into the realm of flexible devices, we demonstrate that it is feasible to grow epitaxial Fe3O4 film, a promising candidate for realizing spintronic devices based on tunneling magnetoresistance, on flexible muscovite. In this study, the heteroepitaxy of Fe3O4/muscovite is characterized by X-ray diffraction, high-resolution transmission electron microscopy, and Raman spectroscopy. The chemical composition and magnetic feature are investigated by a combination of X-ray photoelectron spectroscopy and X-ray magnetic circular dichroism. The electrical and magnetic properties are examined to show the preservation of the primitive properties of Fe3O4. Furthermore, various bending tests are performed to show the tunability of functionalities and to confirm that the heterostructures retain the physical properties under repeated cycles. These results illustrate that the Fe3O4/muscovite heterostructure can be a potential candidate for the applications in flexible spintronics.
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Affiliation(s)
- Ping-Chun Wu
- Max Planck Institute for Chemical Physics of Solids , Noethnitzerstrasse 40, 01187 Dresden, Germany
- Department of Materials Science and Engineering, National Chiao Tung University , Hsinchu 30010, Taiwan
| | - Ping-Fan Chen
- Institute of Physics, Academia Sinica, Taipei 11529, Taiwan
| | - Thi Hien Do
- Institute of Physics, Academia Sinica, Taipei 11529, Taiwan
| | - Ying-Hui Hsieh
- Department of Materials Science and Engineering, National Chiao Tung University , Hsinchu 30010, Taiwan
- Institut fur Angewandte Photophysik, Technische Universitat Dresden , George-Bahr-Strasse 1, 01069 Dresden, Germany
| | - Chun-Hao Ma
- Department of Electrical Engineering, National Tsing Hua University , Hsinchu 30013, Taiwan
| | - Thai Duy Ha
- Department of Electrophysics, National Chiao Tung University , Hsinchu 30010, Taiwan
| | - Kun-Hong Wu
- Department of Physics, National Cheng Kung University , Tainan City 701, Taiwan
| | - Yu-Jia Wang
- Department of Physics, Tsinghua University , Beijing 100084, China
| | - Hao-Bo Li
- Department of Physics, Tsinghua University , Beijing 100084, China
| | - Yi-Chun Chen
- Department of Physics, National Cheng Kung University , Tainan City 701, Taiwan
| | - Jenh-Yih Juang
- Department of Electrophysics, National Chiao Tung University , Hsinchu 30010, Taiwan
| | - Pu Yu
- Department of Physics, Tsinghua University , Beijing 100084, China
| | - Lukas M Eng
- Institut fur Angewandte Photophysik, Technische Universitat Dresden , George-Bahr-Strasse 1, 01069 Dresden, Germany
| | - Chun-Fu Chang
- Max Planck Institute for Chemical Physics of Solids , Noethnitzerstrasse 40, 01187 Dresden, Germany
| | - Po-Wen Chiu
- Department of Electrical Engineering, National Tsing Hua University , Hsinchu 30013, Taiwan
| | - Liu Hao Tjeng
- Max Planck Institute for Chemical Physics of Solids , Noethnitzerstrasse 40, 01187 Dresden, Germany
| | - Ying-Hao Chu
- Department of Materials Science and Engineering, National Chiao Tung University , Hsinchu 30010, Taiwan
- Institute of Physics, Academia Sinica, Taipei 11529, Taiwan
- Department of Electrophysics, National Chiao Tung University , Hsinchu 30010, Taiwan
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20
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Mi CW, Chin YY, Hsiao YF, Fang HW, Luo CW, Wu KH, Uen TM, Lin JY, Lin HJ, Juang JY. Effects of strain on the electronic structure and magnetic properties in SrMn0.5Fe0.5O3. J Phys Condens Matter 2016; 28:345501. [PMID: 27355241 DOI: 10.1088/0953-8984/28/34/345501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The electronic structure and magnetic properties of SrMn0.5Fe0.5O3 powder and films grown on (1 0 0)-SrTiO3 (STO) and (1 0 0)-LaAlO3 (LAO) substrates by pulsed laser deposition (PLD) were investigated by temperature dependent magnetization and soft x-ray absorption. The results exhibit characteristics of 3d (5) Fe(3+), [Formula: see text], and 3d (3) + 3d (4) [Formula: see text] Mn(4+) at room temperature in all samples. However, the features of 3d (5) Fe(3+) and 3d (3) Mn(4+) increased significantly for SMFO/LAO at 35 K, which also displayed substantial competition between antiferromagnetic and ferromagnetic order well-above the Néel temperature of SrFeO3 (T N ~ 134 K). We attributed this to being caused by charge disproportionation resulting from ligand-hole localization, which is more favorable to take place when the sample is under compressive strain.
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Affiliation(s)
- Chun-Wei Mi
- Department of Electrophysics, National Chiao Tung University, Hsinchu 30010, Taiwan
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21
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Lin CM, Liu HT, Zhong SY, Hsu CH, Chiu YT, Tai MF, Juang JY, Chuang YC, Liao YF. Structural Transitions in Nanosized Zn 0.97Al 0.03O Powders under High Pressure Analyzed by in Situ Angle-Dispersive X-ray Diffraction. Materials (Basel) 2016; 9:E561. [PMID: 28773683 PMCID: PMC5456907 DOI: 10.3390/ma9070561] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Revised: 06/28/2016] [Accepted: 07/07/2016] [Indexed: 11/16/2022]
Abstract
Nanosized aluminum-doped zinc oxide Zn1-xAlxO (AZO) powders (AZO-NPs) with x = 0.01, 0.03, 0.06, 0.09 and 0.11 were synthesized by chemical precipitation method. The thermogravimetric analysis (TGA) indicated that the precursors were converted to oxides from hydroxides near 250 °C, which were then heated to 500 °C for subsequent thermal processes to obtain preliminary powders. The obtained preliminary powders were then calcined at 500 °C for three hours. The structure and morphology of the products were measured and characterized by angle-dispersive X-ray diffraction (ADXRD) and scanning electron microscopy (SEM). ADXRD results showed that AZO-NPs with Al content less than 11% exhibited würtzite zinc oxide structure and there was no other impurity phase in the AZO-NPs, suggesting substitutional doping of Al on Zn sites. The Zn0.97Al0.03O powders (A₃ZO-NPs) with grain size of about 21.4 nm were used for high-pressure measurements. The in situ ADXRD measurements revealed that, for loading run, the pressure-induced würtzite (B4)-to-rocksalt (B1) structural phase transition began at 9.0(1) GPa. Compared to the predicted phase-transition pressure of ~12.7 GPa for pristine ZnO nanocrystals of similar grain size (~21.4 nm), the transition pressure for the present A₃ZO-NPs exhibited a reduction of ~3.7 GPa. The significant reduction in phase-transition pressure is attributed to the effects of highly selective site occupation, namely Zn2+ and Al3+, were mainly found in tetrahedral and octahedral sites, respectively.
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Affiliation(s)
- Chih-Ming Lin
- Department of Applied Science, National Hsinchu University of Education, Hsinchu 30014, Taiwan.
| | - Hsin-Tzu Liu
- Department of Chemical Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan.
- Chemical Systems Research Division, Chung-Shan Institute of Science & Technology, Taoyuan 32546, Taiwan.
| | - Shi-Yao Zhong
- Department of Applied Science, National Hsinchu University of Education, Hsinchu 30014, Taiwan.
| | - Chia-Hung Hsu
- Department of Applied Science, National Hsinchu University of Education, Hsinchu 30014, Taiwan.
| | - Yi-Te Chiu
- Department of Applied Science, National Hsinchu University of Education, Hsinchu 30014, Taiwan.
| | - Ming-Fong Tai
- Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan.
| | - Jenh-Yih Juang
- Department of Electrophysics, National Chiao Tung University, Hsinchu 33013, Taiwan.
| | - Yu-Chun Chuang
- National Synchrotron Radiation Research Center, 101 Hsin-Ann Road, Hsinchu Science Park, Hsinchu 30076, Taiwan.
| | - Yen-Fa Liao
- National Synchrotron Radiation Research Center, 101 Hsin-Ann Road, Hsinchu Science Park, Hsinchu 30076, Taiwan.
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22
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Amrillah T, Vandrangi SK, Bitla Y, Do TH, Liao SC, Tsai CY, Chin YY, Liu YT, Lin ML, He Q, Lin HJ, Lee HY, Lai CH, Arenholz E, Juang JY, Chu YH. Tuning the magnetic properties of self-assembled BiFeO3-CoFe2O4 heteroepitaxy by magneto-structural coupling. Nanoscale 2016; 8:8847-8854. [PMID: 27072287 DOI: 10.1039/c5nr09269h] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Magnetic and multiferroic nanocomposites with two distinct phases have been a topic of intense research for their profound potential applications in the field of spintronics. In addition to growing high-quality phase separated heteroepitaxial nanocomposites, the strain engineering that is conducive to enhance the tunability of material properties, in general, and the magnetic properties, in particular, is of utmost importance in exploring new possibilities. Here, we investigated the magneto-structural coupling between antiferromagnetic BiFeO3 (BFO) and ferrimagnetic CoFe2O4 (CFO) in self-assembled vertically aligned nanocomposites grown on LaAlO3 (LAO) and SrTiO3 (STO) substrates. We found that BFO exhibits tetragonal (T) and rhombohedral (R) structures as the stable phases and CFO has high magnetocrystalline anisotropy even in the form of nanocomposites. The temperature and magnetic field dependent magnetizations of T_BFO-CFO/LAO and R_BFO-CFO/STO nanocomposites primarily demonstrate the magnetoelastic coupling between these variants.
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Affiliation(s)
- Tahta Amrillah
- Department of Electrophysics, National Chiao Tung University, Hsinchu 30010, Taiwan.
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23
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Liang WI, Peng CY, Huang R, Kuo WC, Huang YC, Adamo C, Chen YC, Chang L, Juang JY, Schlom DG, Chu YH. Epitaxial integration of a nanoscale BiFeO3 phase boundary with silicon. Nanoscale 2016; 8:1322-1326. [PMID: 26689266 DOI: 10.1039/c5nr07033c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The successful integration of the strain-driven nanoscale phase boundary of BiFeO3 onto a silicon substrate is demonstrated with extraordinary ferroelectricity and ferromagnetism. The detailed strain history is delineated through a reciprocal space mapping technique. We have found that a distorted monoclinic phase forms prior to a tetragonal-like phase, a phenomenon which may correlates with the thermal strain induced during the growth process.
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Affiliation(s)
- Wen-I Liang
- Department of Materials Science and Engineering, National Chiao Tung University, HsinChu, 30010, Taiwan, Republic of China
| | - Chun-Yen Peng
- Department of Materials Science and Engineering, National Chiao Tung University, HsinChu, 30010, Taiwan, Republic of China
| | - Rong Huang
- Key Laboratory of Polar Materials and Devices, Ministry of Education, East China Normal University, Shanghai 200062, People's Republic of China and Nanostructures Research Laboratory, Japan Fine Ceramics Center, Nagoya 456-8587, Japan
| | - Wei-Cheng Kuo
- Department of Electrophysics, National Chiao Tung University, HsinChu, 30010, Taiwan, Republic of China
| | - Yen-Chin Huang
- Department of Physics, National Cheng Kung University, Tainan 70101, Taiwan, Republic of China
| | - Carolina Adamo
- Department of Applied Physics, Stanford University, Stanford, CA 94305, USA
| | - Yi-Chun Chen
- Department of Physics, National Cheng Kung University, Tainan 70101, Taiwan, Republic of China
| | - Li Chang
- Department of Materials Science and Engineering, National Chiao Tung University, HsinChu, 30010, Taiwan, Republic of China
| | - Jenh-Yih Juang
- Department of Electrophysics, National Chiao Tung University, HsinChu, 30010, Taiwan, Republic of China
| | - Darrel G Schlom
- Department of Materials Science and Engineering, Cornell University, Ithaca, NY 14853, USA
| | - Ying-Hao Chu
- Department of Materials Science and Engineering, National Chiao Tung University, HsinChu, 30010, Taiwan, Republic of China and Institute of Physics, Academia Sinica, Taipei 155, Taiwan.
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24
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Chang YM, Ravipati S, Kao PH, Shieh J, Ko FH, Juang JY. Broadband antireflection and field emission properties of TiN-coated Si-nanopillars. Nanoscale 2014; 6:9846-9851. [PMID: 25029029 DOI: 10.1039/c4nr01874e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Broadband antireflection and field emission characteristics of silicon nanopillars (Si-NPs) fabricated by self-masking dry etching in hydrogen-containing plasma were systematically investigated. In particular, the effects of ultrathin (5-20 nm) titanium nitride (TiN) films deposited on Si-NPs by atomic layer deposition (ALD) on the optoelectronic properties were explored. The results showed that by coating the Si-NPs with a thin layer of TiN the antireflection capability of pristine Si-NPs can be significantly improved, especially in the wavelength range of 1000-1500 nm. The enhanced field emission characteristics of these TiN/Si-NP heterostructures suggest that, in addition to the reflectance suppression in the long wavelength range arising from the strong wavelength-dependent refractive index of TiN, the TiN-coating may have also significantly modified the effective work function at the TiN/Si interface as well.
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Affiliation(s)
- Yuan-Ming Chang
- Department of Electrophysics, National Chiao Tung University, Hsinchu 300, Taiwan.
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25
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Hsu HL, Leong KR, Teng IJ, Halamicek M, Juang JY, Jian SR, Qian L, Kherani NP. Reduction of Photoluminescence Quenching by Deuteration of Ytterbium-Doped Amorphous Carbon-Based Photonic Materials. Materials (Basel) 2014; 7:5643-5663. [PMID: 28788152 PMCID: PMC5456179 DOI: 10.3390/ma7085643] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/29/2014] [Revised: 07/21/2014] [Accepted: 07/31/2014] [Indexed: 01/17/2023]
Abstract
In situ Yb-doped amorphous carbon thin films were grown on Si substrates at low temperatures (<200 °C) by a simple one-step RF-PEMOCVD system as a potential photonic material for direct integration with Si CMOS back end-of-line processing. Room temperature photoluminescence around 1 µm was observed via direct incorporation of optically active Yb3+ ions from the selected Yb(fod)₃ metal-organic compound. The partially fluorinated Yb(fod)₃ compound assists the suppression of photoluminescence quenching by substitution of C-H with C-F bonds. A four-fold enhancement of Yb photoluminescence was demonstrated via deuteration of the a-C host. The substrate temperature greatly influences the relative deposition rate of the plasma dissociated metal-organic species, and hence the concentration of the various elements. Yb and F incorporation are promoted at lower substrate temperatures, and suppressed at higher substrate temperatures. O concentration is slightly elevated at higher substrate temperatures. Photoluminescence was limited by the concentration of Yb within the film, the concentration of Yb ions in the +3 state, and the relative amount of quenching due to the various de-excitation pathways associated with the vibrational modes of the host a-C network. The observed wide full-width-at-half-maximum photoluminescence signal is a result of the variety of local bonding environments due to the a-C matrix, and the bonding of the Yb3+ ions to O and/or F ions as observed in the X-ray photoelectron spectroscopy analyses.
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Affiliation(s)
- Hui-Lin Hsu
- Department of Electrical and Computer Engineering, University of Toronto, Toronto, ON M5S 3G4, Canada.
| | - Keith R Leong
- Department of Electrical and Computer Engineering, University of Toronto, Toronto, ON M5S 3G4, Canada.
| | - I-Ju Teng
- Center for Interdisciplinary Science, National Chiao Tung University, Hsinchu 30010, Taiwan.
- Department of Materials Science and Engineering, I-Shou University, Kaohsiung 84001, Taiwan.
| | - Michael Halamicek
- Department of Electrical and Computer Engineering, University of Toronto, Toronto, ON M5S 3G4, Canada.
| | - Jenh-Yih Juang
- Center for Interdisciplinary Science, National Chiao Tung University, Hsinchu 30010, Taiwan.
| | - Sheng-Rui Jian
- Department of Materials Science and Engineering, I-Shou University, Kaohsiung 84001, Taiwan.
| | - Li Qian
- Department of Electrical and Computer Engineering, University of Toronto, Toronto, ON M5S 3G4, Canada.
| | - Nazir P Kherani
- Department of Electrical and Computer Engineering, University of Toronto, Toronto, ON M5S 3G4, Canada.
- Department of Materials Science and Engineering, University of Toronto, Toronto, ON M5S 3E4, Canada.
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26
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Chen SC, Hsieh DH, Jiang H, Liao YK, Lai FI, Chen CH, Luo CW, Juang JY, Chueh YL, Wu KH, Kuo HC. Growth and characterization of Cu(In,Ga)Se2 thin films by nanosecond and femtosecond pulsed laser deposition. Nanoscale Res Lett 2014; 9:280. [PMID: 24959108 PMCID: PMC4059471 DOI: 10.1186/1556-276x-9-280] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/22/2014] [Accepted: 05/09/2014] [Indexed: 06/03/2023]
Abstract
In this work, CuIn1 - x Ga x Se2 (CIGS) thin films were prepared by nanosecond (ns)- and femtosecond (fs)-pulsed laser deposition (PLD) processes. Different film growth mechanisms were discussed in perspective of the laser-produced plasmas and crystal structures. The fs-PLD has successfully improved the inherent flaws, Cu2 - x Se, and air voids ubiquitously observed in ns-PLD-derived CIGS thin films. Moreover, the prominent antireflection and excellent crystalline structures were obtained in the fs-PLD-derived CIGS thin films. The absorption spectra suggest the divergence in energy levels of radiative defects brought by the inhomogeneous distribution of elements in the fs-PLD CIGS, which has also been supported by comparing photoluminescence (PL) spectra of ns- and fs-PLD CIGS thin films at 15 K. Finally, the superior carrier transport properties in fs-PLD CIGS were confirmed by fs pump-probe spectroscopy and four-probe measurements. The present results indicate a promising way for preparing high-quality CIGS thin films via fs-PLD.
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Affiliation(s)
- Shih-Chen Chen
- Department of Electrophysics, National Chiao-Tung University, Hsinchu 30010, Taiwan
| | - Dan-Hua Hsieh
- Department of Photonics and Institute of Electro-Optical Engineering, National Chiao-Tung University, Hsinchu 30010, Taiwan
| | - Hsin Jiang
- Department of Electrophysics, National Chiao-Tung University, Hsinchu 30010, Taiwan
| | - Yu-Kuang Liao
- Department of Electrophysics, National Chiao-Tung University, Hsinchu 30010, Taiwan
| | - Fang-I Lai
- Department of Photonic Engineering, Yuan-Ze University, Taoyuan 32003, Taiwan
| | - Chyong-Hua Chen
- Department of Photonics and Institute of Electro-Optical Engineering, National Chiao-Tung University, Hsinchu 30010, Taiwan
| | - Chih Wei Luo
- Department of Electrophysics, National Chiao-Tung University, Hsinchu 30010, Taiwan
| | - Jenh-Yih Juang
- Department of Electrophysics, National Chiao-Tung University, Hsinchu 30010, Taiwan
| | - Yu-Lun Chueh
- Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Kaung-Hsiung Wu
- Department of Electrophysics, National Chiao-Tung University, Hsinchu 30010, Taiwan
| | - Hao-Chung Kuo
- Department of Photonics and Institute of Electro-Optical Engineering, National Chiao-Tung University, Hsinchu 30010, Taiwan
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27
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Luo CW, Wang HJ, Ku SA, Chen HJ, Yeh TT, Lin JY, Wu KH, Juang JY, Young BL, Kobayashi T, Cheng CM, Chen CH, Tsuei KD, Sankar R, Chou FC, Kokh KA, Tereshchenko OE, Chulkov EV, Andreev YM, Gu GD. Snapshots of Dirac fermions near the Dirac point in topological insulators. Nano Lett 2013; 13:5797-5802. [PMID: 24228733 DOI: 10.1021/nl4021842] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The recent focus on topological insulators is due to the scientific interest in the new state of quantum matter as well as the technology potential for a new generation of THz optoelectronics, spintronics and quantum computations. It is important to elucidate the dynamics of the Dirac fermions in the topologically protected surface state. Hence we utilized a novel ultrafast optical pump mid-infrared probe to explore the dynamics of Dirac fermions near the Dirac point. The femtosecond snapshots of the relaxation process were revealed by the ultrafast optics. Specifically, the Dirac fermion-phonon coupling strength in the Dirac cone was found to increase from 0.08 to 0.19 while Dirac fermions were away from the Dirac point into higher energy states. Further, the energy-resolved transient reflectivity spectra disclosed the energy loss rate of Dirac fermions at room temperature was about 1 meV/ps. These results are crucial to the design of Dirac fermion devices.
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Affiliation(s)
- C W Luo
- Department of Electrophysics and ‡Institute of Physics, National Chiao Tung University , Hsinchu, Taiwan
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28
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Jian SR, Tseng YC, Teng IJ, Juang JY. Dislocation Energetics and Pop-Ins in AlN Thin Films by Berkovich Nanoindentation. Materials (Basel) 2013; 6:4259-4267. [PMID: 28788330 PMCID: PMC5452654 DOI: 10.3390/ma6094259] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/31/2013] [Revised: 09/09/2013] [Accepted: 09/17/2013] [Indexed: 11/29/2022]
Abstract
Nanoindentation-induced multiple pop-ins were observed in the load-displacement curves when the mechanical responses of AlN films grown on c-plane sapphire substrates were investigated by using Berkovich indenters. No evidence of phase transformation is revealed by cross-sectional transmission electron microscopy (XTEM) and selected area diffraction (SAD) analyses. Instead XTEM observations suggest that these “instabilities” resulted from the sudden nucleation of dislocations propagating along the slip systems lying on the {0001} basal planes and the {101¯1} pyramidal planes commonly observed in hexagonal compound semiconductors. Based on this scenario, an energetic estimation of dislocation nucleation is made.
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Affiliation(s)
- Sheng-Rui Jian
- Department of Materials Science and Engineering, I-Shou University, Main Campus: No.1, Sec. 1, Syuecheng Rd., Dashu District, Kaohsiung City 84001, Taiwan.
| | - Yu-Chin Tseng
- Department of Materials Science and Engineering, I-Shou University, Main Campus: No.1, Sec. 1, Syuecheng Rd., Dashu District, Kaohsiung City 84001, Taiwan.
| | - I-Ju Teng
- Centre for Interdisciplinary Science, National Chiao Tung University, Hsinchu 30010, Taiwan.
- Department of Electrophysics, National Chiao Tung University, Hsinchu 30010, Taiwan.
| | - Jenh-Yih Juang
- Centre for Interdisciplinary Science, National Chiao Tung University, Hsinchu 30010, Taiwan.
- Department of Electrophysics, National Chiao Tung University, Hsinchu 30010, Taiwan.
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29
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Jian SR, Chang HW, Tseng YC, Chen PH, Juang JY. Structural and nanomechanical properties of BiFeO3 thin films deposited by radio frequency magnetron sputtering. Nanoscale Res Lett 2013; 8:297. [PMID: 23799923 PMCID: PMC3695780 DOI: 10.1186/1556-276x-8-297] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/28/2013] [Accepted: 06/11/2013] [Indexed: 06/02/2023]
Abstract
The nanomechanical properties of BiFeO3 (BFO) thin films are subjected to nanoindentation evaluation. BFO thin films are grown on the Pt/Ti/SiO2/Si substrates by using radio frequency magnetron sputtering with various deposition temperatures. The structure was analyzed by X-ray diffraction, and the results confirmed the presence of BFO phases. Atomic force microscopy revealed that the average film surface roughness increased with increasing of the deposition temperature. A Berkovich nanoindenter operated with the continuous contact stiffness measurement option indicated that the hardness decreases from 10.6 to 6.8 GPa for films deposited at 350°C and 450°C, respectively. In contrast, Young's modulus for the former is 170.8 GPa as compared to a value of 131.4 GPa for the latter. The relationship between the hardness and film grain size appears to follow closely with the Hall-Petch equation.
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Affiliation(s)
- Sheng-Rui Jian
- Department of Materials Science and Engineering, I-Shou University, Kaohsiung 840, Taiwan
| | - Huang-Wei Chang
- Department of Applied Physics, Tunghai University, Taichung 407, Taiwan
| | - Yu-Chin Tseng
- Department of Materials Science and Engineering, I-Shou University, Kaohsiung 840, Taiwan
| | - Ping-Han Chen
- Department of Applied Physics, Tunghai University, Taichung 407, Taiwan
| | - Jenh-Yih Juang
- Department of Electrophysics, National Chiao Tung University, Hsinchu 300, Taiwan
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30
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Chen YJ, Hsieh YH, Liao SC, Hu Z, Huang MJ, Kuo WC, Chin YY, Uen TM, Juang JY, Lai CH, Lin HJ, Chen CT, Chu YH. Strong magnetic enhancement in self-assembled multiferroic-ferrimagnetic nanostructures. Nanoscale 2013; 5:4449-4453. [PMID: 23584452 DOI: 10.1039/c3nr00104k] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
In the past decade, self-assembled vertical nano-heterostructures have drawn considerable attention because a high interface-to-volume ratio can be used to tailor or create functionalities. We have systematically investigated the magnetic properties of oxide heterostructures consisting of the CoFe2O4 nanopillars embedded in the BiFeO3 matrix using macroscopic magnetization measurements and element-selective soft X-ray absorption magnetic circular dichroism (XMCD) at the Co- and Fe-L2,3 edge. The magnetization and XMCD data show that the total ordered magnetic moment of Co(2+) in CoFe2O4-BiFeO3 nano-heterostructures is strongly enhanced. This study clearly indicates that the high interface-to-volume ratio vertical nanostructure creates a strong ferromagnetic and antiferromagnetic magnetic coupling via an interface. Furthermore, the magnetic coupling can be tuned in the multiferroic-ferrimagnetic self-assembled heterostructures by controlling the spacing between nanopillars.
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Affiliation(s)
- Ying-Jiun Chen
- National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan
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31
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Guo JL, Chiou YD, Liang WI, Liu HJ, Chen YJ, Kuo WC, Tsai CY, Tsai KA, Kuo HH, Hsieh WF, Juang JY, Hsu YJ, Lin HJ, Chen CT, Liao XP, Shi B, Chu YH. Complex oxide-noble metal conjugated nanoparticles. Adv Mater 2013; 25:2040-4. [PMID: 23427105 DOI: 10.1002/adma.201204582] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2012] [Revised: 11/29/2012] [Indexed: 05/20/2023]
Abstract
Hybrid nanoparticles (NPs) composed of multiple components offer new opportunities for next-generation materials. In this study, a paradigm for the noble metal/ternary complex oxide hybrid NPs is reported by adopting pulsed laser ablation in liquids. As model hybrids, gold-spinel heterodimer (Au-CoFe2O4) and gold-pervoskite heterodimer (Au-SrTiO3) NPs are investigated. This work has demonstrated the diverse playgroup of NP conjugation enlarged by complex oxides.
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Affiliation(s)
- Jun-Ling Guo
- Department of Materials Science and Engineering, National Chiao Tung University, HsinChu, Taiwan, ROC
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32
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Chang YM, Kao PH, Tai HM, Wang HW, Lin CM, Lee HY, Juang JY. Enhanced field emission characteristics in metal-coated Si-nanocones. Phys Chem Chem Phys 2013; 15:10761-6. [DOI: 10.1039/c3cp50948f] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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33
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Teng IJ, Hsu HL, Jian SR, Kuo CT, Juang JY. Fabrication of cone-shaped CNF/SiC-coated Si-nanocone composite structures and their excellent field emission performance. Nanoscale 2012; 4:7362-7368. [PMID: 23108379 DOI: 10.1039/c2nr31511d] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Novel cone-shaped carbon nanofiber (CNF)/silicon carbide (SiC)-coated Si-nanocone (Si-NC) composite structures with excellent field emission (FE) performance have been fabricated by a simple microwave plasma chemical vapour deposition process. Transmission electron microscopy analyses reveal that the newly developed cone-shaped composite structures are composed of bamboo-like herringbone CNFs grown vertically on the tips of conical SiC layers with a flat-top Si cone embedded underneath. For this CNF/SiC-coated Si-NC composite array, a ultra-low threshold field of 0.32 V μm(-1) (at 10 mA cm(-2)), a large emission current density of 668 mA cm(-2) at 1.05 V μm(-1), and a field enhancement factor as high as ~48,349 are obtained. In addition, the FE lifetime test performed at a large emission current density of 200 mA cm(-2) under an applied field of 1 V μm(-1) shows no discernible decay during a period of over 260 minutes. We deduce that this superior FE performance can be attributed to the specific bamboo-like herringbone CNFs with numerous open graphitic edges and a faceted top end, and the conical base SiC/Si structures with sufficient adhesion to the substrate surface. Such a novel structure with promising emission characteristics makes it a potential material for electron field emitters.
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Affiliation(s)
- I-Ju Teng
- Department of Materials Science and Engineering, National Chiao Tung University, Hsinchu 30010, Taiwan.
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Chang YM, Lin ML, Lai TY, Lee HY, Lin CM, Wu YCS, Juang JY. Field emission properties of gold nanoparticle-decorated ZnO nanopillars. ACS Appl Mater Interfaces 2012; 4:6676-6682. [PMID: 23148729 DOI: 10.1021/am301848a] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The structural and optoelectronic properties of ZnO nanopillars (ZnO-NPs) grown on Si substrates by the vapor transport deposition method were investigated. In particular, by varying the deposition duration and hence the morphology of the vertically aligned ZnO-NPs, the resultant field emission characteristics were systematically compared. In addition to identifying the advantageous field emission properties exhibited in the pencil-like ZnO-NPs, we observed that by adhering Au nanoparticles on the surface of the ZnO-NPs the turn-on field and the maximum current density can be drastically improved from 3.15 V/μm and 0.44 mA/cm(2) at 5 V/μm for the best ZnO-NPs to 2.65 V/μm and 2.11 mA/cm(2) at 5 V/μm for Au/ZnO-NPs, respectively. The enhancement of field emission characteristics that resulted from Au-nanoparticle decoration is discussed on the basis of charge-transfer-induced band structure modifications.
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Affiliation(s)
- Yuan-Ming Chang
- Department of Electrophysics, National Chiao Tung University, Hsinchu 300, Taiwan.
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35
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Abstract
The structural and nanomechanical properties of GaSe thin films were investigated by means of X-ray diffraction (XRD) and nanoindentation techniques. The GaSe thin films were deposited on Si(111) substrates by pulsed laser deposition. XRD patterns reveal only the pure (000 l)-oriented reflections originating from the hexagonal GaSe phase and no trace of any impurity or additional phases. Nanoindentation results exhibit discontinuities (so-called multiple 'pop-in' events) in the loading segments of the load-displacement curves, and the continuous stiffness measurements indicate that the hardness and Young's modulus of the hexagonal GaSe films are 1.8 ± 0.2 and 65.8 ± 5.6 GPa, respectively.
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Affiliation(s)
- Sheng-Rui Jian
- Department of Materials Science and Engineering, I-Shou University, Main Campus
No.1, Sec. 1, Syuecheng Rd., Dashu District, Kaohsiung, 84001, Taiwan
| | - Shin-An Ku
- Department of Electrophysics, National Chiao Tung University, Hsinchu, 300,
Taiwan
| | - Chih-Wei Luo
- Department of Electrophysics, National Chiao Tung University, Hsinchu, 300,
Taiwan
| | - Jenh-Yih Juang
- Department of Electrophysics, National Chiao Tung University, Hsinchu, 300,
Taiwan
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36
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Luo CW, Wu IH, Cheng PC, Lin JY, Wu KH, Uen TM, Juang JY, Kobayashi T, Chareev DA, Volkova OS, Vasiliev AN. Quasiparticle dynamics and phonon softening in FeSe superconductors. Phys Rev Lett 2012; 108:257006. [PMID: 23004646 DOI: 10.1103/physrevlett.108.257006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2011] [Indexed: 06/01/2023]
Abstract
Quasiparticle dynamics of FeSe single crystals revealed by dual-color transient reflectivity measurements (ΔR/R) provides unprecedented information on Fe-based superconductors. The amplitude of the fast component in ΔR/R clearly gives a competing scenario between spin fluctuations and superconductivity. Together with the transport measurements, the relaxation time analysis further exhibits anomalous changes at 90 and 230 K. The former manifests a structure phase transition as well as the associated phonon softening. The latter suggests a previously overlooked phase transition or crossover in FeSe. The electron-phonon coupling constant λ is found to be 0.16, identical to the value of theoretical calculations. Such a small λ demonstrates an unconventional origin of superconductivity in FeSe.
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Affiliation(s)
- C W Luo
- Department of Electrophysics, National Chiao Tung University, Hsinchu 300, Taiwan.
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Chen SC, Liao YK, Chen HJ, Chen CH, Lai CH, Chueh YL, Kuo HC, Wu KH, Juang JY, Cheng SJ, Hsieh TP, Kobayashi T. Ultrafast carrier dynamics in Cu(In,Ga)Se₂ thin films probed by femtosecond pump-probe spectroscopy. Opt Express 2012; 20:12675-12681. [PMID: 22714296 DOI: 10.1364/oe.20.012675] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Ultrafast carrier dynamics in Cu(In,Ga)Se₂ films are investigated using femtosecond pump-probe spectroscopy. Samples prepared by direct sputtering and co-evaporation processes, which exhibited remarkably different crystalline structures and free carrier densities, were found to result in substantially different carrier relaxation and recombination mechanisms. For the sputtered CIGS films, electron-electron scattering and Auger recombination was observed, whereas for the co-evaporated CIGS films, bandgap renormalization accompanied by band filling effect and hot phonon relaxation was observed. The lifetime of defect-related recombination in the co-evaporated CIGS films is much longer than that in the direct-sputtered CIGS films, reflecting a better quality with higher energy conversion efficiency of the former.
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Affiliation(s)
- Shih-Chen Chen
- Department of Electro-Physics, National Chiao-Tung University, Hsinchu, Taiwan
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Chang YM, Liu MC, Kao PH, Lin CM, Lee HY, Juang JY. Field emission in vertically aligned ZnO/Si-nanopillars with ultra low turn-on field. ACS Appl Mater Interfaces 2012; 4:1411-1416. [PMID: 22288496 DOI: 10.1021/am201667m] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
An effective method of fabricating vertically aligned silicon nanopillars (Si-NPs) was realized by using the self-assembled silver (Ag) nanodots as natural metal-nanomask during dry etching process. The obtained Si-NPs were preferentially aligned along the c-axis direction. Ultrathin ZnO films (~9 nm) were subsequently deposited on the Si-NPs by atomic layer deposition (ALD) to enhance the field emission property. The average diameter of the ZnO/Si-NPs is in the order of tens of nanometers, which enables efficient field emission and gives rise to marked improvement in the field enhancement factor, β. The turn-on field defined by the 10 μA/cm(2) current density criterion is ~0.74 V/μm with an estimated β ≈ 1.33×10(4). The low turn-on field and marked enhancement in β were attributed to the small radius of curvature, high aspect ratio, and perhaps more importantly, proper density distribution of the ZnO/Si-NPs.
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Affiliation(s)
- Yuan-Ming Chang
- Department of Electrophysics, National Chiao Tung University, Hsinchu 300, Taiwan.
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Chang YM, Kao PH, Liu MC, Lin CM, Lee HY, Juang JY. Fabrication and optoelectronic properties of core–shell biomimetic ZnO/Si nanoball arrays. RSC Adv 2012. [DOI: 10.1039/c2ra21817h] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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Chang YM, Shieh J, Chu PY, Lee HY, Lin CM, Juang JY. Enhanced free exciton and direct band-edge emissions at room temperature in ultrathin ZnO films grown on Si nanopillars by atomic layer deposition. ACS Appl Mater Interfaces 2011; 3:4415-4419. [PMID: 21967063 DOI: 10.1021/am201062t] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Room-temperature ultraviolet (UV) luminescence was investigated for the atomic layer deposited ZnO films grown on silicon nanopillars (Si-NPs) fabricated by self-masking dry etching in hydrogen-containing plasma. For films deposited at 200 °C, an intensive UV emission corresponding to free-exciton recombination (~3.31 eV) was observed with a nearly complete suppression of the defect-associated broad visible range emission peak. On the other hand, for ZnO films grown at 25 °C, albeit the appearance of the defect-associated visible emission, the UV emission peak was observed to shift by ~60 meV to near the direct band edge (3.37 eV) recombination emission. The high-resolution transmission electron microscopy (HRTEM) showed that the ZnO films obtained at 25 °C were consisting of ZnO nanocrystals with a mean radius of 2 nm embedded in a largely amorphous matrix. Because the Bohr radius of free-exictons in bulk ZnO is ~2.3 nm, the size confinement effect may have occurred and resulted in the observed direct band edge electron-hole recombination. Additionally, the results also demonstrate order of magnitude enhancement in emission efficiency for the ZnO/Si-NP structure, as compared to that of ZnO directly deposited on Si substrate under the same conditions.
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Affiliation(s)
- Yuan-Ming Chang
- Department of Electrophysics, National Chiao Tung University, Hsinchu 300, Taiwan.
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Liu CH, Chen CH, Chen SY, Yen YT, Kuo WC, Liao YK, Juang JY, Kuo HC, Lai CH, Chen LJ, Chueh YL. Large scale single-crystal Cu(In,Ga)Se2 nanotip arrays for high efficiency solar cell. Nano Lett 2011; 11:4443-4448. [PMID: 21910452 DOI: 10.1021/nl202673k] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
In this paper, we demonstrated direct formation of large area Cu(In,Ga)Se(2) nanotip arrays (CIGS NTRs) by using one step Ar(+) milling process without template. By controlling milling time and incident angles, the length of CIGS NTRs with adjustable tilting orientations can be precisely controlled. Formation criteria of these CIGS NTRs have been discussed in terms of surface curvature, multiple components, and crystal quality, resulting in a highly anisotropic milling effect. The CIGS NTRs have very low reflectance <0.1% at incident wavelengths between 300 to 1200 nm. Open circuit voltage and short circuit current of CIGS NTRs solar cell were measured to be ∼390 mV and ∼22.56 mA/cm(2), yielding the filling factor and the efficiency of 59 and 5.2%, respectively. In contrast to CIGS thin film solar cell with efficiency of 3.2%, the nanostructured CIGS NTRs can have efficiency enhancement of ∼160% due to the higher light absorption ability because of the nanostructure. The merits of current approach include the latest way via template-free direct creating process of nanostructured CIGS NTRs with controllable dimensionality and large scale production without postselenization process.
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Affiliation(s)
- Chin-Hung Liu
- Department of Materials Science and Engineering, National Tsing Hua University , Hsinchu, 30013, Taiwan, ROC
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Li CH, Liu MC, Chiang CL, Li JY, Chen SP, Hsieh TC, Chou YI, Lin YP, Wang PH, Chun MS, Zeng HK, Juang JY. Discharge and photo-luminance properties of a parallel plates electron emission lighting device. Opt Express 2011; 19 Suppl 1:A51-A56. [PMID: 21263712 DOI: 10.1364/oe.19.000a51] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The gas discharge and photo-luminance properties of a planar lighting source featuring highly uniform light emission and mercury-free design were studied. The current density-voltage characteristics and the associated gas discharge of the devices operating with the values of the ratio of electric field to gas pressure (E/p) between 4.3 kV/Torr-cm and 35.7 kV/Torr-cm indicate that the width of the cathode fall extends over the entire gap between the two electrodes and the device is mostly in the obstructed discharge regime. The optical emission analysis confirmed the electron collision-induced gas emissions and strong effect of gas pressure on the phosphor emission when operated at constant current density, both are indicative of the primary roles played by the electron energy.
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Affiliation(s)
- Chia-Hung Li
- Green Energy & Environment Research Laboratories, Industrial Technology Research Institute, 195 Sec 4, Chung-Hsin Road, Chutung 310, Taiwan
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Chang YM, Jian SR, Lee HY, Lin CM, Juang JY. Enhanced visible photoluminescence from ultrathin ZnO films grown on Si-nanowires by atomic layer deposition. Nanotechnology 2010; 21:385705. [PMID: 20798465 DOI: 10.1088/0957-4484/21/38/385705] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Bright room temperature visible emission is obtained in heterostructures consisting of approximately 3.5 nm thick ZnO ultrathin films grown on Si-nanowires produced by means of self-masking dry etching in hydrogen-containing plasma. The ZnO films were deposited on Si-nanowires by using atomic layer deposition (ALD) under an ambient temperature of 25 degrees C. The orders of magnitude enhancement in the intensity of the room temperature photoluminescence peaked around 560 nm in the present ZnO/Si-nanowire heterostructures is presumably due to the high aspect (surface/volume) ratio inherent to the Si-nanowires, which has, in turn, allowed considerably more ZnO material to be grown on the template and led to markedly more efficient visible emission. Moreover, the ordered nanowire structure also features an extremely low reflectance (approximately 0.15%) at 325 nm, which may further enhance the efficiency of emission by effectively trapping the excitation light.
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Affiliation(s)
- Yuan-Ming Chang
- Department of Materials Science and Engineering, I-Shou University, Kaohsiung, Taiwan
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Chang YM, Jian SR, Juang JY. Nanogrids and Beehive-Like Nanostructures Formed by Plasma Etching the Self-Organized SiGe Islands. Nanoscale Res Lett 2010; 5:1456-1463. [PMID: 20730116 PMCID: PMC2920400 DOI: 10.1007/s11671-010-9661-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/19/2010] [Accepted: 05/25/2010] [Indexed: 05/29/2023]
Abstract
A lithography-free method for fabricating the nanogrids and quasi-beehive nanostructures on Si substrates is developed. It combines sequential treatments of thermal annealing with reactive ion etching (RIE) on SiGe thin films grown on (100)-Si substrates. The SiGe thin films deposited by ultrahigh vacuum chemical vapor deposition form self-assembled nanoislands via the strain-induced surface roughening (Asaro-Tiller-Grinfeld instability) during thermal annealing, which, in turn, serve as patterned sacrifice regions for subsequent RIE process carried out for fabricating nanogrids and beehive-like nanostructures on Si substrates. The scanning electron microscopy and atomic force microscopy observations confirmed that the resultant pattern of the obtained structures can be manipulated by tuning the treatment conditions, suggesting an interesting alternative route of producing self-organized nanostructures.
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Affiliation(s)
- Yuan-Ming Chang
- Department of Materials Science and Engineering, I-Shou University, Kaohsiung, 840, Taiwan
| | - Sheng-Rui Jian
- Department of Materials Science and Engineering, I-Shou University, Kaohsiung, 840, Taiwan
| | - Jenh-Yih Juang
- Department of Electrophysics, National Chiao Tung University, Hsinchu, 300, Taiwan
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Lin TH, Shih HC, Hsieh CC, Luo CW, Lin JY, Her JL, Yang HD, Hsu CH, Wu KH, Uen TM, Juang JY. Strain-induced effects on antiferromagnetic ordering and magnetocapacitance in orthorhombic HoMnO(3) thin films. J Phys Condens Matter 2009; 21:026013. [PMID: 21814006 DOI: 10.1088/0953-8984/21/2/026013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We investigated the magnetic and ferroelectric properties of c-axis oriented orthorhombic phase HoMnO(3) (o-HMO in Pbnm symmetry setting) thin films grown on Nb-doped SrTiO(3)(001) substrates. The o-HMO films exhibit an antiferromagnetic ordering near 42 K, irrespective of the orientation of the applied field. However, an additional magnetic ordering occurring around 35 K was observed when the field was applied along the c-axis of o-HMO, which was absent when the field was applied in the ab-plane. The magnetocapacitance measured along the c-axis showed that although there is evidence of dielectric constant enhancement when the temperature is below 35 K the expected abrupt change in dielectric constant appears at a much lower temperature and reaches maximum around 13.5 K, indicating that the low-temperature c-axis polarization might be related to the ordering of the Ho(3+) moment. The lattice constant analyses using x-ray diffraction and the observation of a slight magnetization hysteresis suggest that the weak second magnetic transition along the c-axis at 35 K might be more relevant to the strain-induced effect on antiferromagnetism.
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Affiliation(s)
- T H Lin
- Department of Electrophysics, National Chiao Tung University, Hsinchu 300, Taiwan
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Luo CW, Lee CC, Li CH, Shih HC, Chen YJ, Hsieh CC, Su CH, Tzeng WY, Wu KH, Juang JY, Uen TM, Chen SP, Lin JY, Kobayashi T. Ordered YBCO sub-micron array structures induced by pulsed femtosecond laser irradiation. Opt Express 2008; 16:20610-20616. [PMID: 19065200 DOI: 10.1364/oe.16.020610] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
We report on the formation of organized sub-micron YBa(2)Cu(3)O(7) (YBCO) dots induced by irradiating femtosecond laser pulses on YBCO films prepared by pulse laser deposition with fluence in the range of 0.21 approximately 0.53 J/cm(2). The morphology of the YBCO film surface depends strongly on the laser fluences irradiated. At lower laser fluence (approximately 0.21 J/cm(2)) the morphology was pattern of periodic ripples with sub-micrometer spacing. Slightly increasing the laser fluence to 0.26 J/cm(2) changes the pattern into organized sub-micron dots with diameters ranging from 100 nm to 800 nm and height of 150 nm. Further increase of the laser fluence to over 0.32 J/cm(2), however, appeared to result in massive melting and led to irregular morphology. The mechanism and the implications of the current findings will be discussed. Arrays of YBCO sub-micron dots with T(c) = 89.7 K were obtained.
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Affiliation(s)
- C W Luo
- Department of Electrophysics, National Chiao-Tung University, Hsinchu, Taiwan, ROC.
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Jian SR, Juang JY. Scanned Probe Oxidation on p-GaAs(100) Surface with an Atomic Force Microscopy. Nanoscale Res Lett 2008; 3:249. [PMCID: PMC3244860 DOI: 10.1007/s11671-008-9144-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2008] [Accepted: 06/23/2008] [Indexed: 05/28/2023]
Abstract
Locally anodic oxidation has been performed to fabricate the nanoscale oxide structures onp-GaAs(100) surface, by using an atomic force microscopy (AFM) with the conventional and carbon nanotube (CNT)-attached probes. The results can be utilized to fabricate the oxide nanodots under ambient conditions in noncontact mode. To investigate the conversion of GaAs to oxides, micro-Auger analysis was employed to analyze the chemical compositions. The growth kinetics and the associated mechanism of the oxide nanodots were studied under DC voltages. With the CNT-attached probe the initial growth rate of oxide nanodots is in the order of ~300 nm/s, which is ~15 times larger than that obtained by using the conventional one. The oxide nanodots cease to grow practically as the electric field strength is reduced to the threshold value of ~2 × 107 V cm−1. In addition, results indicate that the height of oxide nanodots is significantly enhanced with an AC voltage for both types of probes. The influence of the AC voltages on controlling the dynamics of the AFM-induced nanooxidation is discussed.
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Affiliation(s)
- Sheng-Rui Jian
- Department of Materials Science and Engineering, I-Shou University, Kaohsiung, 840, Taiwan, ROC
| | - Jenh-Yih Juang
- Department of Electrophysics, National Chiao Tung University, Hsinchu, 300, Taiwan, ROC
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Luo CW, Juang JY, Lin JY, Wu KH, Uen TM, Gou YS. Comment on "Conductivity of underdoped YBa2Cu3O7-delta: evidence for incoherent pair correlations in the pseudogap regime". Phys Rev Lett 2003; 90:179703-179704. [PMID: 12786117 DOI: 10.1103/physrevlett.90.179703] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2002] [Indexed: 05/24/2023]
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Juang JY, Wang SJ, Uen TM, Gou YS, Chang HL, Wang C. Low-field scaling behaviors of global flux pinning in Tl-Ba-Ca-Cu-O thin films. Phys Rev B Condens Matter 1992; 46:1188-1192. [PMID: 10003310 DOI: 10.1103/physrevb.46.1188] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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