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Wu X, Qi L, Iqbal MA, Dai S, Weng X, Wu K, Kang C, Li Z, Zhao D, Tang W, Zhuge F, Zhai T, Ruan S, Zeng YJ. Revealing Strong Flexoelectricity and Optoelectronic Coupling in 2D Ferroelectric CuInP 2S 6 Via Large Strain Gradient. ACS APPLIED MATERIALS & INTERFACES 2024; 16:14038-14046. [PMID: 38445951 DOI: 10.1021/acsami.3c18678] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/07/2024]
Abstract
The interplay between flexoelectric and optoelectronic characteristics provides a paradigm for studying emerging phenomena in various 2D materials. However, an effective way to induce a large and tunable strain gradient in 2D devices remains to be exploited. Herein, we propose a strategy to induce large flexoelectric effect in 2D ferroelectric CuInP2S6 by constructing a 1D-2D mixed-dimensional heterostructure. The strong flexoelectric effect is induced by enormous strain gradient up to 4.2 × 106 m-1 resulting from the underlying ZnO nanowires, which is further confirmed by the asymmetric coercive field and the red-shift in the absorption edge. The induced flexoelectric polarization efficiently boosts the self-powered photodetection performance. In addition, the improved photoresponse has a good correlation with the induced strain gradient, showing a consistent size-dependent flexoelectric effect. The mechanism of flexoelectric and optoelectronic coupling is proposed based on the Landau-Ginzburg-Devonshire double-well model, supported by density functional theory (DFT) calculations. This work provides a brand-new method to induce a strong flexoelectric effect in 2D materials, which is not restricted to crystal symmetry and thus offers unprecedented opportunities for state-of-the-art 2D devices.
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Affiliation(s)
- Xiaokeng Wu
- Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, P. R. China
| | - Lu Qi
- Key Laboratory of Advanced Optical Precision Manufacturing Technology of Guangdong Higher Education Institutes, Shenzhen Technology University, Shenzhen 518118, P. R. China
| | - Muhammad Ahsan Iqbal
- Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, P. R. China
| | - Sichao Dai
- Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, P. R. China
| | - Xiaoliang Weng
- Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, P. R. China
| | - Kewen Wu
- Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, P. R. China
| | - Chenxu Kang
- Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, P. R. China
| | - Zelong Li
- Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, P. R. China
| | - Duo Zhao
- Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, P. R. China
| | - Wei Tang
- Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, P. R. China
| | - Fuwei Zhuge
- State Key Laboratory of Materials Processing and Die and Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology (HUST), Wuhan 430074, P. R. China
- Shenzhen Huazhong University of Science and Technology Research Institute, Shenzhen 518057, P. R. China
| | - Tianyou Zhai
- State Key Laboratory of Materials Processing and Die and Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology (HUST), Wuhan 430074, P. R. China
- Shenzhen Huazhong University of Science and Technology Research Institute, Shenzhen 518057, P. R. China
| | - Shuangchen Ruan
- Key Laboratory of Advanced Optical Precision Manufacturing Technology of Guangdong Higher Education Institutes, Shenzhen Technology University, Shenzhen 518118, P. R. China
| | - Yu-Jia Zeng
- Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, P. R. China
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Iqbal MA, Xie H, Qi L, Jiang WC, Zeng YJ. Recent Advances in Ferroelectric-Enhanced Low-Dimensional Optoelectronic Devices. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2023; 19:e2205347. [PMID: 36634972 DOI: 10.1002/smll.202205347] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Revised: 11/20/2022] [Indexed: 06/17/2023]
Abstract
Ferroelectric (FE) materials, including BiFeO3 , P(VDF-TrFE), and CuInP2 S6 , are a type of dielectric material with a unique, spontaneous electric polarization that can be reversed by applying an external electric field. The combination of FE and low-dimensional materials produces synergies, sparking significant research interest in solar cells, photodetectors (PDs), nonvolatile memory, and so on. The fundamental aspects of FE materials, including the origin of FE polarization, extrinsic FE materials, and FE polarization quantification are first discussed. Next, the state-of-the-art of FE-based optoelectronic devices is focused. How FE materials affect the energy band of channel materials and how device structures influence PD performance are also summarized. Finally, the future directions of this rapidly growing field are discussed.
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Affiliation(s)
- Muhammad Ahsan Iqbal
- Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen, 518060, P. R. China
| | - Haowei Xie
- Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen, 518060, P. R. China
| | - Lu Qi
- Key Laboratory of Advanced Optical Precision Manufacturing Technology of Guangdong Higher Education Institutes, Shenzhen Technology University, Shenzhen, 518118, P. R. China
| | - Wei-Chao Jiang
- Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen, 518060, P. R. China
| | - Yu-Jia Zeng
- Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen, 518060, P. R. China
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Xie H, Kang C, Iqbal MA, Weng X, Wu K, Tang W, Qi L, Zeng YJ. Ferroelectric Tuning of ZnO Ultraviolet Photodetectors. NANOMATERIALS (BASEL, SWITZERLAND) 2022; 12:3358. [PMID: 36234488 PMCID: PMC9565710 DOI: 10.3390/nano12193358] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 09/23/2022] [Accepted: 09/23/2022] [Indexed: 06/16/2023]
Abstract
The ferroelectric field effect transistor (Fe-FET) is considered to be one of the most important low-power and high-performance devices. It is promising to combine a ferroelectric field effect with a photodetector to improve the photodetection performance. This study proposes a strategy for ZnO ultraviolet (UV) photodetectors regulated by a ferroelectric gate. The ZnO nanowire (NW) UV photodetector was tuned by a 2D CuInP2S6 (CIPS) ferroelectric gate, which decreased the dark current and enhanced the responsivity and detectivity to 2.40 × 104 A/W and 7.17 × 1011 Jones, respectively. This strategy was also applied to a ZnO film UV photodetector that was tuned by a P(VDF-TrFE) ferroelectric gate. Lower power consumption and higher performance can be enabled by ferroelectric tuning of ZnO ultraviolet photodetectors, providing new inspiration for the fabrication of high-performance photodetectors.
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Zhang H, Ahn CW, Park JY, Ok JW, Sung JY, Jin JS, Kim HG, Lee JS. Healing Ion-Implanted Semiconductors by Hybrid Microwave Annealing: Activation of Nitrogen-Implanted TiO 2. J Phys Chem Lett 2022; 13:3878-3885. [PMID: 35470660 DOI: 10.1021/acs.jpclett.2c00220] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
In order to recover the damaged structure of a nitrogen-implanted TiO2 (N-I-TiO2) photoanode, hybrid microwave annealing (HMA) is proposed as an alternative postannealing process instead of conventional thermal annealing (CTA). Compared to CTA, HMA provides distinctive advantages: (i) facile transformation of the interstitial N-N states into substitutional N-Ti states, (ii) better preservation of the ion-implanted nitrogen in TiO2, and (iii) effective alleviation of lattice strain and reconstruction of the broken bonds. As a result, the HMA-activated photoanode improves the photocurrent density by a factor of ∼3.2 from 0.29 to 0.93 mA cm-2 at 1.23 VRHE and the incident photon-to-current conversion efficiency (IPCE) from ∼2.9% to ∼10.5% at 430 nm relative to those of the as-prepared N-I-TiO2 photoanode in photoelectrochemical water oxidation, which are much better than those of the CTA-activated photoanode (0.58 mA cm-2 at 1.23 VRHE and IPCE of 5.7% at 430 nm), especially in the visible light region (≥420 nm).
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Affiliation(s)
- Hemin Zhang
- College of Materials Science and Engineering, Sichuan University, Engineering Research Center of Alternative Energy Materials and Devices, Ministry of Education, Chengdu 610065, China
| | - Chang Won Ahn
- Department of Physics, University of Ulsan, Ulsan, 680-749, Republic of Korea
| | - Jin Yong Park
- Busan Center, Korea Basic Science Institute, Busan, 609-735, Republic of Korea
| | - Jung-Woo Ok
- Busan Center, Korea Basic Science Institute, Busan, 609-735, Republic of Korea
| | - Ji Yeong Sung
- Busan Center, Korea Basic Science Institute, Busan, 609-735, Republic of Korea
| | - Jong Sung Jin
- Busan Center, Korea Basic Science Institute, Busan, 609-735, Republic of Korea
| | - Hyun Gyu Kim
- Busan Center, Korea Basic Science Institute, Busan, 609-735, Republic of Korea
| | - Jae Sung Lee
- School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology, 50 UNIST-gil, Ulsan 44919, Republic of Korea
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Qi L, Ruan S, Zeng YJ. Review on Recent Developments in 2D Ferroelectrics: Theories and Applications. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021; 33:e2005098. [PMID: 33577141 DOI: 10.1002/adma.202005098] [Citation(s) in RCA: 66] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Revised: 09/28/2020] [Indexed: 06/12/2023]
Abstract
Although only a few 2D materials have been predicted to possess ferroelectricity, 2D ferroelectrics are expected to play a dominant role in the upcoming nano era as important functional materials. The ferroelectric properties of 2D ferroelectrics are significantly different than those of traditional bulk ferroelectrics owing to their intrinsic size and surface effects. To date, 2D ferroelectrics have been reported to exhibit diverse properties ranging from bulk photovoltaic and piezoelectric/pyroelectric effects to the spontaneous valley and spin polarization. These properties are either dependent on ferroelectric polarization or coupled with it for easy electric control, thus making 2D ferroelectrics applicable to multifunctional nanodevices. At present, cumulative efforts are being made to explore 2D ferroelectrics in theories, experiments, and applications. Herein, such theories and methods are briefly introduced. Subsequently, intrinsic and extrinsic origins of 2D ferroelectricity are separately summarized. In addition, invented or laboratory-validated 2D ferroelectric-based applications are listed. Finally, the existing challenges and prospects of 2D ferroelectrics are discussed.
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Affiliation(s)
- Lu Qi
- Key laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen, 518060, P. R. China
| | - Shuangchen Ruan
- College of New Materials and New Energies, Shenzhen Technology University, Shenzhen, 518118, P. R. China
| | - Yu-Jia Zeng
- Key laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen, 518060, P. R. China
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Hu L, Cao L, Li L, Duan J, Liao X, Long F, Zhou J, Xiao Y, Zeng YJ, Zhou S. Two-dimensional magneto-photoconductivity in non-van der Waals manganese selenide. MATERIALS HORIZONS 2021; 8:1286-1296. [PMID: 34821921 DOI: 10.1039/d1mh00009h] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Deficient intrinsic species and suppressed Curie temperatures (Tc) in two-dimensional (2D) magnets are major barriers for future spintronic applications. As an alternative, delaminating non-van der Waals (vdW) magnets can offset these shortcomings and involve robust bandgaps to explore 2D magneto-photoconductivity at ambient temperature. Herein, non-vdW α-MnSe2 is first delaminated as quasi-2D nanosheets for the study of emerging semiconductor, ferromagnetism and magneto-photoconductivity behaviors. Abundant nonstoichiometric surfaces induce the renormalization of the band structure and open a bandgap of 1.2 eV. The structural optimization strengthens ferromagnetic super-exchange interactions between the nearest-neighbor Mn2+, which enables us to achieve a high Tc of 320 K well above room temperature. The critical fitting of magnetization and transport measurements both verify that it is of quasi-2D nature. The above observations are evidenced by multiple microscopic and macroscopic characterization tools, in line with the prediction of first-principles calculations. Profiting from the negative magnetoresistance effect, the self-powered infrared magneto-photoconductivity performance including a responsivity of 330.4 mA W-1 and a millisecond-level response speed are further demonstrated. Such merits stem from the synergistic modulation of magnetic and light fields on photogenerated carriers. This provides a new strategy to manipulate both charge and spin in 2D non-vdW systems and displays their alluring prospects in magneto-photodetection.
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Affiliation(s)
- Liang Hu
- Key Laboratory of Novel Materials for Sensor of Zhejiang Province, Institute of Advanced Magnetic Materials, Hangzhou Dianzi University, Hangzhou 310018, P. R. China.
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Zhang J, Zhang H, Zhang H, Ma Y, Chen X, Meng F, Qi S, Chen Y, Hu F, Zhang Q, Liu B, Shen B, Zhao W, Han W, Sun J. Long-Range Magnetic Order in Oxide Quantum Wells Hosting Two-Dimensional Electron Gases. ACS APPLIED MATERIALS & INTERFACES 2020; 12:28775-28782. [PMID: 32459951 DOI: 10.1021/acsami.0c05332] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
To incorporate spintronics functionalities into two-dimensional devices, it is strongly desired to get two-dimensional electron gases (2DEGs) with high spin polarization. Unfortunately, the magnetic characteristics of the typical 2DEG at the LaAlO3/SrTiO3 interface are very weak due to the nonmagnetic character of SrTiO3 and LaAlO3. While most of the previous works focused on perovskite oxides, here, we extended the exploration for magnetic 2DEG beyond the scope of perovskite combinations, composing 2DEG with SrTiO3 and NaCl-structured EuO that owns a large saturation magnetization and a fairly high Curie temperature. We obtained the 2DEGs that show long-range magnetic order and thus unusual behaviors marked by isotropic butterfly shaped magnetoresistance and remarkable anomalous Hall effect. We found evidence for the presence of more conductive domain walls than elsewhere in the oxide layer where the 2DEG resides. More than that, a relation between interfacial magnetism and carrier density is established. On this basis, the intermediate magnetic states between short-range and long-range ordered states can be achieved. The present work provides guidance for the design of high-performance magnetic 2DEGs.
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Affiliation(s)
- Jine Zhang
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Hui Zhang
- Fert Beijing Institute, School of Microelectronics, Beijing Advanced Innovation Center for Big Data and Brain Computing, Beihang University, Beijing 100191, People's Republic of China
| | - Hongrui Zhang
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Yang Ma
- International Centre for Quantum Materials, School of Physics, Peking University, Beijing 100871, People's Republic of China
- Collaborative Innovation Centre of Quantum Matter, Beijing 100871, People's Republic of China
| | - Xiaobing Chen
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Fanqi Meng
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
| | - Shaojin Qi
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Yuansha Chen
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
| | - Fengxia Hu
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, People's Republic of China
| | - Qinghua Zhang
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
| | - Banggui Liu
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Baogen Shen
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, People's Republic of China
| | - Weisheng Zhao
- Fert Beijing Institute, School of Microelectronics, Beijing Advanced Innovation Center for Big Data and Brain Computing, Beihang University, Beijing 100191, People's Republic of China
| | - Wei Han
- International Centre for Quantum Materials, School of Physics, Peking University, Beijing 100871, People's Republic of China
- Collaborative Innovation Centre of Quantum Matter, Beijing 100871, People's Republic of China
| | - Jirong Sun
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, People's Republic of China
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Li W, Zhan X, Song X, Si S, Chen R, Liu J, Wang Z, He J, Xiao X. A Review of Recent Applications of Ion Beam Techniques on Nanomaterial Surface Modification: Design of Nanostructures and Energy Harvesting. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2019; 15:e1901820. [PMID: 31166661 DOI: 10.1002/smll.201901820] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Revised: 05/13/2019] [Indexed: 05/23/2023]
Abstract
Nanomaterials have gained plenty of research interest because of their excellent performance, which is derived from their small size and special structure. In practical applications, to acquire nanomaterials with high performance, many methods have been used to modulate the structure and components of materials. To date, ion beam techniques have extensively been applied for modulating the performance of various nanomaterials. Energetic ion beams can modulate the surface morphology and chemical components of nanomaterials. In addition, ion beam techniques have also been used to fabricate nanomaterials, including 2D materials, nanoparticles, and nanowires. Compared with conventional methods, ion beam techniques, including ion implantation, ion irradiation, and focused ion beam, are all pure physical processes; these processes do not introduce any impurities into the target materials. In addition, ion beam techniques exhibit high controllability and repeatability. Here, recent progress in ion beam techniques for nanomaterial surface modification is systematically summarized and existing challenges and potential solutions are presented.
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Affiliation(s)
- Wenqing Li
- Department of Physics and Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, Hubei Nuclear Solid Physics Key Laboratory and Center for Ion Beam Application, Wuhan University, Wuhan, 430072, P. R. China
| | - Xueying Zhan
- CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, National Center for Nanoscience and Technology, Beijing, 100190, P. R. China
| | - Xianyin Song
- Department of Physics and Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, Hubei Nuclear Solid Physics Key Laboratory and Center for Ion Beam Application, Wuhan University, Wuhan, 430072, P. R. China
| | - Shuyao Si
- Department of Physics and Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, Hubei Nuclear Solid Physics Key Laboratory and Center for Ion Beam Application, Wuhan University, Wuhan, 430072, P. R. China
| | - Rui Chen
- Department of Physics and Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, Hubei Nuclear Solid Physics Key Laboratory and Center for Ion Beam Application, Wuhan University, Wuhan, 430072, P. R. China
| | - Jing Liu
- Department of Physics and Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, Hubei Nuclear Solid Physics Key Laboratory and Center for Ion Beam Application, Wuhan University, Wuhan, 430072, P. R. China
| | - Zhenxing Wang
- CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, National Center for Nanoscience and Technology, Beijing, 100190, P. R. China
| | - Jun He
- CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, National Center for Nanoscience and Technology, Beijing, 100190, P. R. China
| | - Xiangheng Xiao
- Department of Physics and Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, Hubei Nuclear Solid Physics Key Laboratory and Center for Ion Beam Application, Wuhan University, Wuhan, 430072, P. R. China
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Li H, Wang C, Li D, Homm P, Menghini M, Locquet JP, Van Haesendonck C, Van Bael MJ, Ruan S, Zeng YJ. Magnetic orders and origin of exchange bias in Co clusters embedded oxide nanocomposite films. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2019; 31:155301. [PMID: 30658346 DOI: 10.1088/1361-648x/aafff0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Magnetic nanoparticles embedded oxide semiconductors are interesting candidates for spintronics in view of combining ferromagnetic (FM) and semiconducting properties. In this work, Co-ZnO and Co-V2O3 nanocomposite thin films are synthesized by Co ion implantation in crystalline thin films. Magnetic orders vary with the implantation fluence in Co-ZnO, where superparamagnetic (SPM) order appears in the low-fluence films (2 × 1016 and 4 × 1016 ions cm-2) and FM order co-exists with the SPM phase in high-fluence films (1 × 1017 ions cm-2). Exchange bias (EB) appears in the high-fluence films, with an EB field of about 100 Oe at 2 K and a blocking temperature of around 100 K. On the other hand, Co-V2O3 thin films with an implantation fluence of 3.5 × 1016 ions cm-2 exhibit a clear antiferromagnetic (AFM) coupling at low temperatures without the EB effect. The different magnetic behavior of the Co-implanted films with different Co content leads us to conclude that the observed EB effect in the Co-ZnO films results from the FM/AFM coupling between sizable Co nanoparticles and their CoO/Co3O4 surroundings in the (Zn,Co)O matrix. On the other hand, the absence of EB effect in Co-V2O3 appears to be due to the small size of the FM Co nanoparticles in spite of an AFM magnetic order. Detailed studies of magnetic orders and EB effect in magnetic nanocomposite semiconductors can pave the way for their application in spintronics.
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Affiliation(s)
- Hui Li
- Shenzhen Key Laboratory of Laser Engineering, College of Optoelectronic Engineering, Shenzhen University, Nanhai Boulevard 3688, Shenzhen 518060, People's Republic of China. Center for Advanced Material Diagnostic Technology, Shenzhen Technology University, No. 3002, Lantian Road, Pingshan District, Shenzhen 518118, People's Republic of China
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Chen J, Huang S, Long Y, Wu J, Li H, Li Z, Zeng YJ, Ruan S. Fabrication of ZnO/Red Phosphorus Heterostructure for Effective Photocatalytic H₂ Evolution from Water Splitting. NANOMATERIALS 2018; 8:nano8100835. [PMID: 30326555 PMCID: PMC6215150 DOI: 10.3390/nano8100835] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Revised: 10/04/2018] [Accepted: 10/11/2018] [Indexed: 11/29/2022]
Abstract
Photocatalysis is a green technique that can convert solar energy to chemical energy, especially in H2 production from water splitting. In this study, ZnO and red phosphorus (ZnO/RP) heterostructures were fabricated through a facile calcination method for the first time, which showed the considerable photocatalytic activity of H2 evolution. The photocatalytic activities of heterostructures with different ratios of RP have been investigated in detail. Compared to bare ZnO, ZnO/RP heterostructures exhibit a 20.8-fold enhancement for H2 production and furthermore overcome the photocorrosion issue of ZnO. The improved photocatalytic activities highly depend on the synergistic effect of the high migration efficiency of photo-induced electron–hole pairs with the inhibited charge carrier recombination on the surface. The presented strategy can also be applied to other semiconductors for various optoelectronics applications.
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Affiliation(s)
- Jiaqi Chen
- Shenzhen Key Laboratory of Laser Engineering, College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China.
| | - Shaolong Huang
- Shenzhen Key Laboratory of Laser Engineering, College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China.
| | - Yaojia Long
- Shenzhen Key Laboratory of Laser Engineering, College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China.
| | - Jiahao Wu
- Shenzhen Key Laboratory of Laser Engineering, College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China.
| | - Hui Li
- Shenzhen Key Laboratory of Laser Engineering, College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China.
| | - Zhao Li
- Shenzhen Key Laboratory of Laser Engineering, College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China.
| | - Yu-Jia Zeng
- Shenzhen Key Laboratory of Laser Engineering, College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China.
| | - Shuangchen Ruan
- Shenzhen Key Laboratory of Laser Engineering, College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China.
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Lin R, Hu L, Wang J, Zhang W, Ruan S, Zeng YJ. Raman scattering enhancement of a single ZnO nanorod decorated with Ag nanoparticles: synergies of defects and plasmons. OPTICS LETTERS 2018; 43:2244-2247. [PMID: 29762563 DOI: 10.1364/ol.43.002244] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Accepted: 04/11/2018] [Indexed: 06/08/2023]
Abstract
Surface-enhanced Raman scattering (SERS) of a single ZnO nanorod (NR) is demonstrated by coating with Ag nanoparticles (NPs). An enhancement factor of 1.2×103 and 4.4×102 has been obtained for E2 (high) mode (437 cm-1) and A1 (TO) mode (378 cm-1), respectively. Electron paramagnetic resonance measurements reveal an unintentional donor state in ZnO NRs. The enhancement of deep-level emission and micro-absorption mapping of a single ZnO NR further confirms the presence of the donor state. The SERS is believed to result from the charge transfer between ZnO NRs and Ag NPs, which can be enhanced by the empty donor state in ZnO. Finally, single ZnO NRs coated with Ag can be used as good SERS substrates for small molecule detection. This Letter highlights the interaction between point defects and the SERS effect down to a single semiconductor NR.
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12
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Sapkota KR, Chen W, Maloney FS, Poudyal U, Wang W. Magnetoresistance manipulation and sign reversal in Mn-doped ZnO nanowires. Sci Rep 2016; 6:35036. [PMID: 27739442 PMCID: PMC5064367 DOI: 10.1038/srep35036] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Accepted: 09/23/2016] [Indexed: 11/22/2022] Open
Abstract
We report magnetoresistance (MR) manipulation and sign reversal induced by carrier concentration modulation in Mn-doped ZnO nanowires. At low temperatures positive magnetoresistance was initially observed. When the carrier concentration was increased through the application of a gate voltage, the magnetoresistance also increased and reached a maximum value. However, further increasing the carrier concentration caused the MR to decrease, and eventually an MR sign reversal from positive to negative was observed. An MR change from a maximum positive value of 25% to a minimum negative value of 7% was observed at 5 K and 50 KOe. The observed MR behavior was modeled by considering combined effects of quantum correction to carrier conductivity and bound magnetic polarons. This work could provide important insights into the mechanisms that govern magnetotransport in dilute magnetic oxides, and it also demonstrated an effective approach to manipulating magnetoresistance in these materials that have important spintronic applications.
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Affiliation(s)
- Keshab R. Sapkota
- Department of Physics and Astronomy, University of Wyoming, Laramie WY, USA
| | - Weimin Chen
- Department of Physics and Astronomy, University of Wyoming, Laramie WY, USA
| | - F. Scott Maloney
- Department of Physics and Astronomy, University of Wyoming, Laramie WY, USA
| | - Uma Poudyal
- Department of Physics and Astronomy, University of Wyoming, Laramie WY, USA
| | - Wenyong Wang
- Department of Physics and Astronomy, University of Wyoming, Laramie WY, USA
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13
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Modepalli V, Jin MJ, Park J, Jo J, Kim JH, Baik JM, Seo C, Kim J, Yoo JW. Gate-Tunable Spin Exchange Interactions and Inversion of Magnetoresistance in Single Ferromagnetic ZnO Nanowires. ACS NANO 2016; 10:4618-4626. [PMID: 26964013 DOI: 10.1021/acsnano.6b00921] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Electrical control of ferromagnetism in semiconductor nanostructures offers the promise of nonvolatile functionality in future semiconductor spintronics. Here, we demonstrate a dramatic gate-induced change of ferromagnetism in ZnO nanowire (NW) field-effect transistors (FETs). Ferromagnetism in our ZnO NWs arose from oxygen vacancies, which constitute deep levels hosting unpaired electron spins. The magnetic transition temperature of the studied ZnO NWs was estimated to be well above room temperature. The in situ UV confocal photoluminescence (PL) study confirmed oxygen vacancy mediated ferromagnetism in the studied ZnO NW FET devices. Both the estimated carrier concentration and temperature-dependent conductivity reveal the studied ZnO NWs are at the crossover of the metal-insulator transition. In particular, gate-induced modulation of the carrier concentration in the ZnO NW FET significantly alters carrier-mediated exchange interactions, which causes even inversion of magnetoresistance (MR) from negative to positive values. Upon sweeping the gate bias from -40 to +50 V, the MRs estimated at 2 K and 2 T were changed from -11.3% to +4.1%. Detailed analysis on the gate-dependent MR behavior clearly showed enhanced spin splitting energy with increasing carrier concentration. Gate-voltage-dependent PL spectra of an individual NW device confirmed the localization of oxygen vacancy-induced spins, indicating that gate-tunable indirect exchange coupling between localized magnetic moments played an important role in the remarkable change of the MR.
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Affiliation(s)
- Vijayakumar Modepalli
- School of Materials Science and Engineering-Low dimensional Carbon Materials Center, Ulsan National Institute of Science and Technology , Ulsan 689-798, Republic of Korea
| | - Mi-Jin Jin
- School of Materials Science and Engineering-Low dimensional Carbon Materials Center, Ulsan National Institute of Science and Technology , Ulsan 689-798, Republic of Korea
| | - Jungmin Park
- School of Materials Science and Engineering-Low dimensional Carbon Materials Center, Ulsan National Institute of Science and Technology , Ulsan 689-798, Republic of Korea
| | - Junhyeon Jo
- School of Materials Science and Engineering-Low dimensional Carbon Materials Center, Ulsan National Institute of Science and Technology , Ulsan 689-798, Republic of Korea
| | - Ji-Hyun Kim
- School of Materials Science and Engineering-Low dimensional Carbon Materials Center, Ulsan National Institute of Science and Technology , Ulsan 689-798, Republic of Korea
| | - Jeong Min Baik
- School of Materials Science and Engineering-Low dimensional Carbon Materials Center, Ulsan National Institute of Science and Technology , Ulsan 689-798, Republic of Korea
| | - Changwon Seo
- Center for Integrated Nanostructure Physics, Institute for Basic Science, Sungkyunkwan University , Suwon 440-746, Republic of Korea
- Department of Energy Science, Sungkyunkwan University , Suwon 440-746, Republic of Korea
| | - Jeongyong Kim
- Center for Integrated Nanostructure Physics, Institute for Basic Science, Sungkyunkwan University , Suwon 440-746, Republic of Korea
- Department of Energy Science, Sungkyunkwan University , Suwon 440-746, Republic of Korea
| | - Jung-Woo Yoo
- School of Materials Science and Engineering-Low dimensional Carbon Materials Center, Ulsan National Institute of Science and Technology , Ulsan 689-798, Republic of Korea
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14
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Imani R, Drašler B, Kononenko V, Romih T, Eleršič K, Jelenc J, Junkar I, Remškar M, Drobne D, Kralj-Iglič V, Iglič A. Growth of a Novel Nanostructured ZnO Urchin: Control of Cytotoxicity and Dissolution of the ZnO Urchin. NANOSCALE RESEARCH LETTERS 2015; 10:441. [PMID: 26573932 PMCID: PMC4646880 DOI: 10.1186/s11671-015-1145-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Accepted: 11/05/2015] [Indexed: 06/05/2023]
Abstract
The applications of zinc oxide (ZnO) nanowires (NWs) in implantable wireless devices, such as diagnostic nanobiosensors and nanobiogenerators, have recently attracted enormous attention due to their unique properties. However, for these implantable nanodevices, the biocompatibility and the ability to control the behaviour of cells in contact with ZnO NWs are demanded for the success of these implantable devices, but to date, only a few contrasting results from their biocompatibility can be found. There is a need for more research about the biocompatibility of ZnO nanostructures and the adhesion and viability of cells on the surface of ZnO nanostructures. Here, we introduce synthesis of a new nature-inspired nanostructured ZnO urchin, with the dimensions of the ZnO urchin's acicula being controllable. To examine the biocompatibility and behaviour of cells in contact with the ZnO urchin, the Madin-Darby canine kidney (MDCK) epithelial cell line was chosen as an in vitro experimental model. The results of the viability assay indicated that, compared to control, the number of viable cells attached to the surface of the ZnO urchin and its surrounding area were reduced. The measurements of the Zn contents of cell media confirmed ZnO dissolution, which suggests that the ZnO dissolution in cell culture medium could lead to cytotoxicity. A purposeful reduction of ZnO cytotoxicity was achieved by surface coating of the ZnO urchin with poly(vinylidene fluorid-co-hexafluoropropylene) (PVDF-HFP), which changed the material matrix to slow the Zn ion release and consequently reduce the cytotoxicity of the ZnO urchin without reducing its functionality.
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Affiliation(s)
- Roghayeh Imani
- Laboratory of Biophysics, Faculty of Electrical Engineering, University of Ljubljana, Tržaška 25, Ljubljana, SI-1000, Slovenia.
- Laboratory of Clinical Biophysics, Faculty of Health Sciences, University of Ljubljana, Ljubljana, SI-1000, Slovenia.
| | - Barbara Drašler
- Department of Biology, Biotechnical Faculty, University of Ljubljana, Večna pot 111, SI-1000, Ljubljana, Slovenia.
| | - Veno Kononenko
- Department of Biology, Biotechnical Faculty, University of Ljubljana, Večna pot 111, SI-1000, Ljubljana, Slovenia.
| | - Tea Romih
- Department of Biology, Biotechnical Faculty, University of Ljubljana, Večna pot 111, SI-1000, Ljubljana, Slovenia.
| | - Kristina Eleršič
- Department of Surface Engineering and Optoelectronics, Jožef Stefan Institute, Jamova 39, Ljubljana, SI-1000, Slovenia.
| | - Janez Jelenc
- Solid State Physics Department, Jožef Stefan Institute, Jamova 39, SI-1000, Ljubljana, Slovenia.
| | - Ita Junkar
- Department of Surface Engineering and Optoelectronics, Jožef Stefan Institute, Jamova 39, Ljubljana, SI-1000, Slovenia.
| | - Maja Remškar
- Solid State Physics Department, Jožef Stefan Institute, Jamova 39, SI-1000, Ljubljana, Slovenia.
| | - Damjana Drobne
- Department of Biology, Biotechnical Faculty, University of Ljubljana, Večna pot 111, SI-1000, Ljubljana, Slovenia.
| | - Veronika Kralj-Iglič
- Laboratory of Clinical Biophysics, Faculty of Health Sciences, University of Ljubljana, Ljubljana, SI-1000, Slovenia.
| | - Aleš Iglič
- Laboratory of Biophysics, Faculty of Electrical Engineering, University of Ljubljana, Tržaška 25, Ljubljana, SI-1000, Slovenia.
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15
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Zeng YJ, Gauquelin N, Li DY, Ruan SC, He HP, Egoavil R, Ye ZZ, Verbeeck J, Hadermann J, Van Bael MJ, Van Haesendonck C. Co-Rich ZnCoO Nanoparticles Embedded in Wurtzite Zn1-xCoxO Thin Films: Possible Origin of Superconductivity. ACS APPLIED MATERIALS & INTERFACES 2015; 7:22166-22171. [PMID: 26387766 DOI: 10.1021/acsami.5b06363] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Co-rich ZnCoO nanoparticles embedded in wurtzite Zn0.7Co0.3O thin films are grown by pulsed laser deposition on a Si substrate. Local superconductivity with an onset Tc at 5.9 K is demonstrated in the hybrid system. The unexpected superconductivity probably results from Co3+ in the Co-rich ZnCoO nanoparticles or from the interface between the Co-rich nanoparticles and the Zn0.7Co0.3O matrix.
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Affiliation(s)
- Yu-Jia Zeng
- Shenzhen Key Laboratory of Laser Engineering, College of Optoelectronic Engineering, Shenzhen University , Shenzhen, 518060, People's Republic of China
- Solid State Physics and Magnetism Section, KU Leuven , Celestijnenlaan 200 D, BE-3001 Leuven, Belgium
- State Key Laboratory of Silicon Materials, Department of Materials Science and Engineering, Zhejiang University , Hangzhou 310027, People's Republic of China
| | - Nicolas Gauquelin
- Electron Microscopy for Materials Science (EMAT), University of Antwerp , Groenenborgerlaan 171, BE-2020 Antwerp, Belgium
| | - Dan-Ying Li
- Solid State Physics and Magnetism Section, KU Leuven , Celestijnenlaan 200 D, BE-3001 Leuven, Belgium
| | - Shuang-Chen Ruan
- Shenzhen Key Laboratory of Laser Engineering, College of Optoelectronic Engineering, Shenzhen University , Shenzhen, 518060, People's Republic of China
| | - Hai-Ping He
- State Key Laboratory of Silicon Materials, Department of Materials Science and Engineering, Zhejiang University , Hangzhou 310027, People's Republic of China
| | - Ricardo Egoavil
- Electron Microscopy for Materials Science (EMAT), University of Antwerp , Groenenborgerlaan 171, BE-2020 Antwerp, Belgium
| | - Zhi-Zhen Ye
- State Key Laboratory of Silicon Materials, Department of Materials Science and Engineering, Zhejiang University , Hangzhou 310027, People's Republic of China
| | - Johan Verbeeck
- Electron Microscopy for Materials Science (EMAT), University of Antwerp , Groenenborgerlaan 171, BE-2020 Antwerp, Belgium
| | - Joke Hadermann
- Electron Microscopy for Materials Science (EMAT), University of Antwerp , Groenenborgerlaan 171, BE-2020 Antwerp, Belgium
| | - Margriet J Van Bael
- Solid State Physics and Magnetism Section, KU Leuven , Celestijnenlaan 200 D, BE-3001 Leuven, Belgium
| | - Chris Van Haesendonck
- Solid State Physics and Magnetism Section, KU Leuven , Celestijnenlaan 200 D, BE-3001 Leuven, Belgium
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16
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Zeng YJ, Schouteden K, Amini MN, Ruan SC, Lu YF, Ye ZZ, Partoens B, Lamoen D, Van Haesendonck C. Electronic Band Structures and Native Point Defects of Ultrafine ZnO Nanocrystals. ACS APPLIED MATERIALS & INTERFACES 2015; 7:10617-10622. [PMID: 25923131 DOI: 10.1021/acsami.5b02545] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Ultrafine ZnO nanocrystals with a thickness down to 0.25 nm are grown by a metalorganic chemical vapor deposition method. Electronic band structures and native point defects of ZnO nanocrystals are studied by a combination of scanning tunneling microscopy/spectroscopy and first-principles density functional theory calculations. Below a critical thickness of ∼1 nm ZnO adopts a graphitic-like structure and exhibits a wide band gap similar to its wurtzite counterpart. The hexagonal wurtzite structure, with a well-developed band gap evident from scanning tunneling spectroscopy, is established for a thickness starting from ∼1.4 nm. With further increase of the thickness to 2 nm, VO-VZn defect pairs are easily produced in ZnO nanocrystals due to the self-compensation effect in highly doped semiconductors.
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Affiliation(s)
- Yu-Jia Zeng
- †Shenzhen Key Laboratory of Laser Engineering, College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, P. R. China
- ‡Solid State Physics and Magnetism Section, KU Leuven, Celestijnenlaan 200 D, BE-3001 Leuven, Belgium
| | - Koen Schouteden
- ‡Solid State Physics and Magnetism Section, KU Leuven, Celestijnenlaan 200 D, BE-3001 Leuven, Belgium
| | | | - Shuang-Chen Ruan
- †Shenzhen Key Laboratory of Laser Engineering, College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, P. R. China
| | - Yang-Fan Lu
- §State Key Laboratory of Silicon Materials, Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, P. R. China
| | - Zhi-Zhen Ye
- §State Key Laboratory of Silicon Materials, Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, P. R. China
| | | | | | - Chris Van Haesendonck
- ‡Solid State Physics and Magnetism Section, KU Leuven, Celestijnenlaan 200 D, BE-3001 Leuven, Belgium
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17
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Li DY, Zeng YJ, Batuk D, Pereira LMC, Ye ZZ, Fleischmann C, Menghini M, Nikitenko S, Hadermann J, Temst K, Vantomme A, Van Bael MJ, Locquet JP, Van Haesendonck C. Relaxor ferroelectricity and magnetoelectric coupling in ZnO-Co nanocomposite thin films: beyond multiferroic composites. ACS APPLIED MATERIALS & INTERFACES 2014; 6:4737-4742. [PMID: 24598535 DOI: 10.1021/am4053877] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
ZnO-Co nanocomposite thin films are synthesized by combination of pulsed laser deposition of ZnO and Co ion implantation. Both superparamagnetism and relaxor ferroelectricity as well as magnetoelectric coupling in the nanocomposites have been demonstrated. The unexpected relaxor ferroelectricity is believed to be the result of the local lattice distortion induced by the incorporation of the Co nanoparticles. Magnetoelectric coupling can be attributed to the interaction between the electric dipole moments and the magnetic moments, which are both induced by the incorporation of Co. The introduced ZnO-Co nanocomposite thin films are different from conventional strain-mediated multiferroic composites.
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Affiliation(s)
- D Y Li
- Laboratory of Solid-State Physics and Magnetism and ‡Instituut voor Kern-en Stralingsfysica, KU Leuven , Celestijnenlaan 200 D, BE-3001 Leuven, Belgium
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18
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Zhou W, Liu R, Tang D, Zou B. The effect of dopant and optical micro-cavity on the photoluminescence of Mn-doped ZnSe nanobelts. NANOSCALE RESEARCH LETTERS 2013; 8:314. [PMID: 23829706 PMCID: PMC3706239 DOI: 10.1186/1556-276x-8-314] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/14/2013] [Accepted: 06/07/2013] [Indexed: 06/02/2023]
Abstract
Pure and Mn-doped ZnSe nanobelts were synthesized by a convenient thermal evaporation method. Scanning electron microscopy, X-ray powder diffraction, energy dispersive X-ray spectroscopy and corresponding element mapping, and transmission electron microscope were used to examine the morphology, phase structure, crystallinity, composition, and growth direction of as-prepared nanobelts. Raman spectra were used to confirm the effective doping of Mn2+ into ZnSe nanobelts. Micro-photoluminescence (PL) spectra were used to investigate the emission property of as-prepared samples. A dominant trapped-state emission band is observed in single ZnSeMn nanobelt. However, we cannot observe the transition emission of Mn ion in this ZnSeMn nanobelt, which confirm that Mn powder act as poor dopant. There are weak near-bandgap emission and strong 4T1 → 6A1 transition emission of Mn2+ in single ZnSeMnCl2 and ZnSeMn(CH3COO)2 nanobelt. More interesting, the 4T1 → 6A1 transition emission in ZnSeMn(CH3COO)2 nanobelt split into multi-bands. PL mapping of individual splitted sub-bands were carried out to explore the origin of multi-bands. These doped nanobelts with novel multi-bands emission can find application in frequency convertor and wavelength-tunable light emission devices.
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Affiliation(s)
- Weichang Zhou
- Key Laboratory of Low-Dimensional Quantum Structures and Quantum Control of Ministry of Education, College of Physics and Information Science, Hunan Normal University, Changsha 410081, China
| | - Ruibin Liu
- Beijing Key Laboratory of Nanophotonics and Ultrafine Optoelectronic Systems, School of Materials Science and Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Dongsheng Tang
- Key Laboratory of Low-Dimensional Quantum Structures and Quantum Control of Ministry of Education, College of Physics and Information Science, Hunan Normal University, Changsha 410081, China
| | - Bingsuo Zou
- Beijing Key Laboratory of Nanophotonics and Ultrafine Optoelectronic Systems, School of Materials Science and Engineering, Beijing Institute of Technology, Beijing 100081, China
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19
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Chiu SP, Lu JG, Lin JJ. Quantum-interference transport through surface layers of indium-doped ZnO nanowires. NANOTECHNOLOGY 2013; 24:245203. [PMID: 23689960 DOI: 10.1088/0957-4484/24/24/245203] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
We have fabricated indium-doped ZnO (IZO) nanowires (NWs) and carried out four-probe electrical-transport measurements on two individual NWs with geometric diameters of ≈70 and ≈90 nm in a wide temperature T interval of 1-70 K. The NWs reveal overall charge conduction behavior characteristic of disordered metals. In addition to the T dependence of resistance R, we have measured the magnetoresistance (MR) in magnetic fields applied either perpendicular or parallel to the NW axis. Our R(T) and MR data in different T intervals are consistent with the theoretical predictions of the one- (1D), two- (2D) or three-dimensional (3D) weak-localization (WL) and the electron-electron interaction (EEI) effects. In particular, a few dimensionality crossovers in the two effects are observed. These crossover phenomena are consistent with the model of a 'core-shell-like structure' in individual IZO NWs, where an outer shell of thickness t (~15-17 nm) is responsible for the quantum-interference transport. In the WL effect, as the electron dephasing length Lφ gradually decreases with increasing T from the lowest measurement temperatures, a 1D-to-2D dimensionality crossover takes place around a characteristic temperature where Lφ approximately equals d, an effective NW diameter which is slightly smaller than the geometric diameter. As T further increases, a 2D-to-3D dimensionality crossover occurs around another characteristic temperature where Lφ approximately equals t (<d). In the EEI effect, a 2D-to-3D dimensionality crossover takes place when the thermal diffusion length LT progressively decreases with increasing T and approaches t. However, a crossover to the 1D EEI effect is not seen because LT < d even at T = 1 K in our IZO NWs. Furthermore, we explain the various inelastic electron scattering processes which govern Lφ. This work demonstrates the complex and rich nature of the charge conduction properties of group-III metal-doped ZnO NWs. This work also strongly indicates that the surface-related conduction processes are essential to doped semiconductor nanostructures.
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Affiliation(s)
- Shao-Pin Chiu
- NCTU-RIKEN Joint Research Laboratory and Institute of Physics, National Chiao Tung University, Hsinchu 30010, Taiwan
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20
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Ye J, Ter Lim S, Bosman M, Gu S, Zheng Y, Tan HH, Jagadish C, Sun X, Teo KL. Spin-polarized wide electron slabs in functionally graded polar oxide heterostructures. Sci Rep 2012; 2:533. [PMID: 22833785 PMCID: PMC3404416 DOI: 10.1038/srep00533] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2012] [Accepted: 07/09/2012] [Indexed: 11/24/2022] Open
Abstract
We report on the high mobility wide electron slabs with enhanced correlation effects by tailoring the polarization effects in a functionally graded ZnMgO/ZnO heterostructures. The characteristics of three-dimensional (3D) spreading electrons are evidenced by the capacitance-voltage profiling and the quantization of 3D Fermi surface in magneto-transport measurements. Despite the weak spin-orbit interaction, such electron slabs are spin-polarized with a large zero-field spin splitting energy, which is induced by the carrier-mediated ferromagnetism. Our results suggest that the vast majority of electrons are localized at the surface magnetic moment which does not allow spin manipulations, and only in the region visited by the itinerant carriers that the ferromagnetic exchange interactions via coupling to the surface local moments contribute to the spin transport. The host ferromagnetism is likely due to the formation of Zn cation vacancies on the surface regime induced by the stabilization mechanism and strain-relaxation in ZnMgO polar ionic surface.
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Affiliation(s)
- Jiandong Ye
- School of Electronics Science and Engineering, Nanjing University, 210093 PR China.
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