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Cai X, Xu L. A Piezoelectrically Excited ZnO Nanowire Mass Sensor with Closed-Loop Detection at Room Temperature. MICROMACHINES 2022; 13:2242. [PMID: 36557541 PMCID: PMC9788434 DOI: 10.3390/mi13122242] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 12/14/2022] [Accepted: 12/14/2022] [Indexed: 06/17/2023]
Abstract
One-dimensional nanobeam mass sensors offer an unprecedented ability to measure tiny masses or even the mass of individual molecules or atoms, enabling many interesting applications in the fields of mass spectrometry and atomic physics. However, current nano-beam mass sensors suffer from poor real-time test performance and high environment requirements. This paper proposes a piezoelectrically excited ZnO nanowire (NW) mass sensor with closed-loop detection at room temperature to break this limitation. It is detected that the designed piezo-excited ZnO NW could operate at room temperature with a resonant frequency of 417.35 MHz, a quality factor of 3010, a mass sensitivity of -8.1 Hz/zg, and a resolution of 192 zg. The multi-field coupling dynamic model of ZnO NW mass sensor under piezoelectric excitation was established and solved. The nonlinear amplitude-frequency characteristic formula, frequency formula, modal function, sensitivity curve, and linear operating interval were obtained. The ZnO NW mass sensor was fabricated by a top-down method and its response to ethanol gas molecules was tested at room temperature. Experiments show that the sensor has high sensitivity, good closed-loop tracking performance, and high linearity, which provides great potential for the detection of biochemical reaction process of biological particles based on mechanics.
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2
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Hwang HY, Baek H, Yi GC, Jho YD. Nanoscale mapping of surface strain in tapered nanorods using confocal photoluminescence spectroscopy. NANOTECHNOLOGY 2022; 33:485703. [PMID: 35998510 DOI: 10.1088/1361-6528/ac8bd9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Accepted: 08/22/2022] [Indexed: 06/15/2023]
Abstract
The strain occurs spontaneously at the heterogeneous interfaces of virtually all crystalline materials. Consequently, the analysis across multiple interfaces requires a complementary characterization scheme with a resolution that fits the deformation scale. By implementing two-photon confocal laser scanning nanoscopy with an axial resolution of 10 nm, we extract the surface strain from the photoluminescence (PL) spectra, epitomized by a 2-fold enhancement at the tapered tips in comparison to the substrate of ZnO nanorods. We firstly traced the well-established contribution from quantum confinement (QC) to PL shift in three geometrically classified regions: (I) a strongly tapered region where the diameter increases from 3 to 20 nm; (II) a weakly tapered region with a gradually increasing diameter from 20 to 58 nm; (III) round cylindrical region interfacing the sapphire substrate. The measured PL shift influenced by the deformation is significantly stronger than the attained QC effect. Particularly, surface strain at the strongly tapered region turned out to drastically increase the PL shift which matches well with the analysis based on the surface to volume ratio incorporating mechanical parameters such as the compliance tensor component, strain dislocation constant, and surface stress. The surface strain increased at a lower temperature, further disclosing its inherent dependence on the thermal expansion coefficients in clear contrast to the temperature-invariant characteristics of QC.
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Affiliation(s)
- Hyeong-Yong Hwang
- Clarendon Laboratory, Department of Physics, University of Oxford, Oxford OX1 3PU, United Kingdom
| | - Hyeonjun Baek
- Department of Physics, Sogang University, Seoul 04107, Republic of Korea
| | - Gyu-Chul Yi
- Department of Physics and Astronomy, and Institute of Applied Physics, Seoul National University, Seoul 08826, Republic of Korea
| | - Young-Dahl Jho
- School of Electrical Engineering and Computer Science, Gwangju Institute of Science and Technology, Gwangju 61005, Republic of Korea
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3
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Kim MJ, Yun TG, Noh JY, Kang MJ, Pyun JC. Photothermal Structural Dynamics of Au Nanofurnace for In Situ Enhancement in Desorption and Ionization. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2021; 17:e2103745. [PMID: 34618393 DOI: 10.1002/smll.202103745] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 08/25/2021] [Indexed: 06/13/2023]
Abstract
Fundamental properties of nanostructured substrates govern the performance of laser desorption/ionization mass spectrometry (LDI-MS); however, limited studies have elucidated the desorption/ionization mechanism based on the physicochemical properties of substrates. Herein, the enhancement in desorption/ionization is investigated using a hybrid matrix of Au nanoisland-functionalized ZnO nanotubes (AuNI-ZNTs). The underlying origin is explored in terms of the photo-electronic and -thermal properties of the matrix. This is the first study to report the effect of laser-induced surface restructuring/melting phenomenon on the LDI-MS performance. AuNI plays a central role as a photothermal nanofurnace, which facilitates the internal energy transfer from the AuNI to the adsorbed analytes by reconstruction in the structurally dynamic AuNI and therefore favors the desorption process. Moreover, piezoelectricity is driven in situ in the AuNI-ZNT hybrid, which modulates the overall band structure and thereby promotes the ionization process. Ultimately, high LDI-MS performance is demonstrated by analyzing small metabolites of fatty acids and monosaccharides, which are challenged to be detected in conventional LDI-MS. This study emphasizing the understanding of matrix properties can provide insights into the design and development of a novel nanomaterial as an efficient LDI matrix. Furthermore, the developed hybrid matrix can overcome the major hurdles existing in conventional LDI-MS.
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Affiliation(s)
- Moon-Ju Kim
- Department of Materials and Science and Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul, 03722, Republic of Korea
| | - Tae Gyeong Yun
- Department of Materials and Science and Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul, 03722, Republic of Korea
| | - Joo-Yoon Noh
- Department of Materials and Science and Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul, 03722, Republic of Korea
| | - Min-Jung Kang
- Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea
| | - Jae-Chul Pyun
- Department of Materials and Science and Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul, 03722, Republic of Korea
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4
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Liu Q, Nie Y, Shang J, Kou L, Zhan H, Sun Z, Bo A, Gu Y. Exceptional Deformability of Wurtzite Zinc Oxide Nanowires with Growth Axial Stacking Faults. NANO LETTERS 2021; 21:4327-4334. [PMID: 33989003 DOI: 10.1021/acs.nanolett.1c00883] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
To ensure reliability and facilitate the strain engineering of zinc oxide (ZnO) nanowires (NWs), it is significant to understand their flexibility thoroughly. In this study, single-crystalline ZnO NWs with rich axial pyramidal I (π1) and prismatic stacking faults (SFs) are synthesized by a metal oxidation method. Bending properties of the as-synthesized ZnO NWs are investigated at the atomic scale using an in situ high-resolution transmission electron microscopy (HRTEM) technique. It is revealed that the SF-rich structures can foster multiple inelastic deformation mechanisms near room temperature, including active axial SFs' migration, deformation twinning and detwinning process in the NWs with growth π1 SFs, and prevalent nucleation and slip of perfect dislocations with a continuous increased bending strain, leading to tremendous bending strains up to 20% of the NWs. Our results record ultralarge bending deformations and provide insights into the deformation mechanisms of single-crystalline ZnO NWs with rich axial SFs.
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Affiliation(s)
- Qiong Liu
- School of Mechanical, Medical, and Process Engineering, Queensland University of Technology (QUT), Brisbane, Queensland 4001, Australia
| | - Yihan Nie
- School of Mechanical, Medical, and Process Engineering, Queensland University of Technology (QUT), Brisbane, Queensland 4001, Australia
| | - Jing Shang
- School of Mechanical, Medical, and Process Engineering, Queensland University of Technology (QUT), Brisbane, Queensland 4001, Australia
| | - Liangzhi Kou
- School of Mechanical, Medical, and Process Engineering, Queensland University of Technology (QUT), Brisbane, Queensland 4001, Australia
| | - Haifei Zhan
- School of Mechanical, Medical, and Process Engineering, Queensland University of Technology (QUT), Brisbane, Queensland 4001, Australia
- Department of Civil Engineering, Zhejiang University, Hangzhou 310058, China
| | - Ziqi Sun
- School of Chemistry and Physics, Queensland University of Technology (QUT), Brisbane, Queensland 4001, Australia
- Center for Materials Science, Queensland University of Technology (QUT), Brisbane, Queensland 4001, Australia
| | - Arixin Bo
- School of Mechanical, Medical, and Process Engineering, Queensland University of Technology (QUT), Brisbane, Queensland 4001, Australia
- INM-Leibniz Institute for New Materials, Saarbrücken 66123, Germany
| | - Yuantong Gu
- School of Mechanical, Medical, and Process Engineering, Queensland University of Technology (QUT), Brisbane, Queensland 4001, Australia
- Center for Materials Science, Queensland University of Technology (QUT), Brisbane, Queensland 4001, Australia
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5
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Peng F, Xu W, Hu Y, Fu W, Li H, Lin J, Xiao Y, Wu Z, Wang W, Lu C. The design of an inner-motile waste-energy-driven piezoelectric catalytic system. NEW J CHEM 2021. [DOI: 10.1039/d1nj00993a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A kind of waste-energy-driven catalytic system was explored for the first time using magnetically actuated artificial cilia.
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6
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Liu Z, Fu X, Zhang DB. Strain gradient induced spatially indirect excitons in single crystalline ZnO nanowires. NANOSCALE 2020; 12:19083-19087. [PMID: 32945824 DOI: 10.1039/d0nr03563g] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Spatially indirect excitons are important not only for the exploration of intriguing many-body effects but also for the development of applications such as solar cells with high efficiency. This type of exciton usually exists in heterostructures. Using the generalized Bloch theorem coupled with the density-functional tight-binding method, we reveal that spatially indirect excitons may emerge in single crystalline ZnO nanowires under bending. The underlying mechanism is attributed to the formation of an effective type-II band alignment due to the strain-gradient of the bent nanowires. Our finding paves a new route to realize spatially indirect excitons by strain engineering.
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Affiliation(s)
- Zhao Liu
- Beijing Computational Science Research Center, Beijing 100193, China.
| | - Xuewen Fu
- School of Physics, Nankai University, Tianjin 300071, China
| | - Dong-Bo Zhang
- College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875, China and Beijing Computational Science Research Center, Beijing 100193, China.
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7
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Origin of magnetic properties in carbon implanted ZnO nanowires. Sci Rep 2018; 8:7758. [PMID: 29773822 PMCID: PMC5958067 DOI: 10.1038/s41598-018-25948-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Accepted: 04/23/2018] [Indexed: 11/09/2022] Open
Abstract
Various synchrotron radiation-based spectroscopic and microscopic techniques are used to elucidate the room-temperature ferromagnetism of carbon-doped ZnO-nanowires (ZnO-C:NW) via a mild C+ ion implantation method. The photoluminescence and magnetic hysteresis loops reveal that the implantation of C reduces the number of intrinsic surface defects and increases the saturated magnetization of ZnO-NW. The interstitial implanted C ions constitute the majority of defects in ZnO-C:NW as confirmed by the X-ray absorption spectroscopic studies. The X-ray magnetic circular dichroism spectra of O and C K-edge respectively indicate there is a reduction in the number of unpaired/dangling O 2p bonds in the surface region of ZnO-C:NW and the C 2p-derived states of the implanted C ions strongly affect the net spin polarization in the surface and bulk regions of ZnO-C:NW. Furthermore, these findings corroborate well with the first-principles calculations of C-implanted ZnO in surface and bulk regions, which highlight the stability of implanted C for the suppression and enhancement of the ferromagnetism of the ZnO-C:NW in the surface region and bulk phase, respectively.
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8
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Lewis RB, Corfdir P, Küpers H, Flissikowski T, Brandt O, Geelhaar L. Nanowires Bending over Backward from Strain Partitioning in Asymmetric Core-Shell Heterostructures. NANO LETTERS 2018; 18:2343-2350. [PMID: 29570304 DOI: 10.1021/acs.nanolett.7b05221] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The flexibility and quasi-one-dimensional nature of nanowires offer wide-ranging possibilities for novel heterostructure design and strain engineering. In this work, we realize arrays of extremely and controllably bent nanowires comprising lattice-mismatched and highly asymmetric core-shell heterostructures. Strain sharing across the nanowire heterostructures is sufficient to bend vertical nanowires over backward to contact either neighboring nanowires or the substrate itself, presenting new possibilities for designing nanowire networks and interconnects. Photoluminescence spectroscopy on bent-nanowire heterostructures reveals that spatially varying strain fields induce charge carrier drift toward the tensile-strained outside of the nanowires, and that the polarization response of absorbed and emitted light is controlled by the bending direction. This unconventional strain field is employed for light emission by placing an active region of quantum dots at the outer side of a bent nanowire to exploit the carrier drift and tensile strain. These results demonstrate how bending in nanoheterostructures opens up new degrees of freedom for strain and device engineering.
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Affiliation(s)
- Ryan B Lewis
- Paul-Drude-Institut für Festkörperelektronik , Hausvogteiplatz 5-7 , 10117 Berlin , Germany
| | - Pierre Corfdir
- Paul-Drude-Institut für Festkörperelektronik , Hausvogteiplatz 5-7 , 10117 Berlin , Germany
| | - Hanno Küpers
- Paul-Drude-Institut für Festkörperelektronik , Hausvogteiplatz 5-7 , 10117 Berlin , Germany
| | - Timur Flissikowski
- Paul-Drude-Institut für Festkörperelektronik , Hausvogteiplatz 5-7 , 10117 Berlin , Germany
| | - Oliver Brandt
- Paul-Drude-Institut für Festkörperelektronik , Hausvogteiplatz 5-7 , 10117 Berlin , Germany
| | - Lutz Geelhaar
- Paul-Drude-Institut für Festkörperelektronik , Hausvogteiplatz 5-7 , 10117 Berlin , Germany
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9
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Im H, Park K, Kim J, Kim D, Lee J, Lee JA, Park J, Ahn JP. Strain Mapping and Raman Spectroscopy of Bent GaP and GaAs Nanowires. ACS OMEGA 2018; 3:3129-3135. [PMID: 31458573 PMCID: PMC6641494 DOI: 10.1021/acsomega.8b00063] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Accepted: 02/21/2018] [Indexed: 06/09/2023]
Abstract
Strain engineering of nanowires (NWs) has been recognized as a powerful strategy for tuning the optical and electronic properties of nanoscale semiconductors. Therefore, the characterization of the strains with nanometer-scale spatial resolution is of great importance for various promising applications. In the present work, we synthesized single-crystalline zinc blende phase GaP and GaAs NWs using the chemical vapor transport method and visualized their bending strains (up to 3%) with high precision using the nanobeam electron diffraction technique. The strain mapping at all crystallographic axes revealed that (i) maximum strain exists along the growth direction ([111]) with the tensile and compressive strains at the outer and inner parts, respectively; (ii) the opposite strains appeared along the perpendicular direction ([2̅11]); and (iii) the tensile strain was larger than the coexisting compressive strain at all axes. The Raman spectrum collected for individual bent NWs showed the peak broadening and red shift of the transverse optical modes that were well-correlated with the strain maps. These results are consistent with the larger mechanical modulus of GaP than that of GaAs. Our work provides new insight into the bending strain of III-V semiconductors, which is of paramount importance in the performance of flexible or bendable electronics.
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Affiliation(s)
- Hyung
Soon Im
- Department
of Chemistry, Korea University, Sejong 30019, Korea
| | - Kidong Park
- Department
of Chemistry, Korea University, Sejong 30019, Korea
| | - Jundong Kim
- Department
of Chemistry, Korea University, Sejong 30019, Korea
| | - Doyeon Kim
- Department
of Chemistry, Korea University, Sejong 30019, Korea
| | - Jinha Lee
- Department
of Chemistry, Korea University, Sejong 30019, Korea
| | - Jung Ah Lee
- Department
of Chemistry, Korea University, Sejong 30019, Korea
| | - Jeunghee Park
- Department
of Chemistry, Korea University, Sejong 30019, Korea
| | - Jae-Pyoung Ahn
- Korea
Advanced Analysis Center, Korea Institute
of Science and Technology, Seoul 136-791, Korea
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10
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Zhang C, Kim DH, Huang X, Sun XY, Aimon NM, Chua SJ, Ross CA. Magnetic and Photoluminescent Coupling in SrTi 0.87Fe 0.13O 3-δ/ZnO Vertical Nanocomposite Films. ACS APPLIED MATERIALS & INTERFACES 2017; 9:32359-32368. [PMID: 28853275 DOI: 10.1021/acsami.7b08741] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Self-assembled growth of SrTi0.87Fe0.13O3-δ (STF)/ZnO vertical nanocomposite films by combinatorial pulsed laser deposition is described. The nanocomposite films form vertically aligned columnar epitaxial nanostructures on SrTiO3 substrates, in which the STF shows room-temperature magnetism. The magnetic properties are discussed in terms of strain states, oxygen vacancies, and microstructures. The nanocomposites exhibit magneto-photoluminescent coupling behavior that the near-band-edge emission of ZnO is shifted as a function of magnetic field.
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Affiliation(s)
- Chen Zhang
- Department of Materials Science and Engineering, Massachusetts Institute of Technology , 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
- Singapore-MIT Alliance, National University of Singapore , 4 Engineering Drive 3, Singapore 117576
| | - Dong Hun Kim
- Department of Materials Science and Engineering, Massachusetts Institute of Technology , 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Xiaohu Huang
- Institute of Materials Research and Engineering , 2 Fusionopolis Way, Singapore 138634
| | - Xue Yin Sun
- Department of Materials Science and Engineering, Massachusetts Institute of Technology , 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Nicolas M Aimon
- Department of Materials Science and Engineering, Massachusetts Institute of Technology , 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Soo Jin Chua
- Singapore-MIT Alliance, National University of Singapore , 4 Engineering Drive 3, Singapore 117576
- Institute of Materials Research and Engineering , 2 Fusionopolis Way, Singapore 138634
| | - Caroline A Ross
- Department of Materials Science and Engineering, Massachusetts Institute of Technology , 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
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11
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Kim Y, Im HS, Park K, Kim J, Ahn JP, Yoo SJ, Kim JG, Park J. Bent Polytypic ZnSe and CdSe Nanowires Probed by Photoluminescence. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2017; 13:1603695. [PMID: 28296175 DOI: 10.1002/smll.201603695] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Revised: 01/22/2017] [Indexed: 06/06/2023]
Abstract
Nanowires (NWs) have witnessed tremendous development over the past two decades owing to their varying potential applications. Semiconductor NWs often contain stacking faults due to the presence of coexisting phases, which frequently hampers their use. Herein, it is investigated how stacking faults affect the optical properties of bent ZnSe and CdSe NWs, which are synthesized using the vapor transport method. Polytypic zinc blende-wurtzite structures are produced for both these NWs by altering the growth conditions. The NWs are bent by the mechanical buckling of poly(dimethylsilioxane), and micro-photoluminescence (PL) spectra were then collected for individual NWs with various bending strains (0-2%). The PL measurements show peak broadening and red shifts of the near-band-edge emission as the bending strain increases, indicating that the bandgap decreases with increasing the bending strain. Remarkably, the bandgap decrease is more significant for the polytypic NWs than for the single phase NWs. This work provides insights into flexible electronic devices of 1D nanostructures by engineering the polytypic structures.
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Affiliation(s)
- Yejin Kim
- Department of Chemistry, Korea University, Jochiwon, 339-700, Republic of Korea
| | - Hyung Soon Im
- Department of Chemistry, Korea University, Jochiwon, 339-700, Republic of Korea
| | - Kidong Park
- Department of Chemistry, Korea University, Jochiwon, 339-700, Republic of Korea
| | - Jundong Kim
- Department of Chemistry, Korea University, Jochiwon, 339-700, Republic of Korea
| | - Jae-Pyoung Ahn
- Advanced Analysis Center, Korea Institute of Science and Technology, Seoul, 136-791, Republic of Korea
| | - Seung Jo Yoo
- Division of Electron Microscopic Research, Korea Basic Science Institute, Daejeon, 305-806, Republic of Korea
| | - Jin-Gyu Kim
- Division of Electron Microscopic Research, Korea Basic Science Institute, Daejeon, 305-806, Republic of Korea
| | - Jeunghee Park
- Department of Chemistry, Korea University, Jochiwon, 339-700, Republic of Korea
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12
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Strain Gradient Modulated Exciton Evolution and Emission in ZnO Fibers. Sci Rep 2017; 7:40658. [PMID: 28084427 PMCID: PMC5234005 DOI: 10.1038/srep40658] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Accepted: 12/09/2016] [Indexed: 11/18/2022] Open
Abstract
One-dimensional semiconductor can undergo large deformation including stretching and bending. This homogeneous strain and strain gradient are an easy and effective way to tune the light emission properties and the performance of piezo-phototronic devices. Here, we report that with large strain gradients from 2.1–3.5% μm−1, free-exciton emission was intensified, and the free-exciton interaction (FXI) emission became a prominent FXI-band at the tensile side of the ZnO fiber. These led to an asymmetric variation in energy and intensity along the cross-section as well as a redshift of the total near-band-edge (NBE) emission. This evolution of the exciton emission was directly demonstrated using spatially resolved CL spectrometry combined with an in situ tensile-bending approach at liquid nitrogen temperature for individual fibers and nanowires. A distinctive mechanism of the evolution of exciton emission is proposed: the enhancement of the free-exciton-related emission is attributed to the aggregated free excitons and their interaction in the narrow bandgap in the presence of high bandgap gradients and a transverse piezoelectric field. These results might facilitate new approaches for energy conversion and sensing applications via strained nanowires and fibers.
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13
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Fu XW, Li CZ, Fang L, Liu DM, Xu J, Yu DP, Liao ZM. Strain-Gradient Modulated Exciton Emission in Bent ZnO Wires Probed by Cathodoluminescence. ACS NANO 2016; 10:11469-11474. [PMID: 28024321 DOI: 10.1021/acsnano.6b07206] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Photoelectrical properties of semiconductor nanostructures are expected to be improved significantly by strain engineering. Besides the local strain, the strain gradient is promising to tune the luminescence properties by modifying the crystal symmetry. Here, we report the investigation of strain-gradient induced symmetry-breaking effect on excitonic states in pure bending ZnO microwires by high spatial-resolved cathodoluminescence at low temperature of 80 K. In addition to the local-strain induced light emission peak shift, the bound exciton emission photon energy shows an extraordinary jump of ∼16.6 meV at a high strain-gradient of 1.22% μm-1, which is ascribed to the strain gradient induced symmetry-breaking. Such a symmetry-breaking lifts the energy degeneracy of the electronic band structures, which significantly modifies the electron-hole interactions and the fine structures of the bound exciton states. These results provide a further understanding of the strain gradient effect on the excitonic states and possess a potential for the applications in optoelectronic devices.
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Affiliation(s)
| | | | - Liang Fang
- State Key Laboratory of Tribology, Tsinghua University , Beijing 100084, China
| | - Da-Meng Liu
- State Key Laboratory of Tribology, Tsinghua University , Beijing 100084, China
| | | | - Da-Peng Yu
- Department of Physics, South University of Science and Technology of China , Shenzhen 518055, China
| | - Zhi-Min Liao
- Collaborative Innovation Center of Quantum Matter , Beijing 100190, China
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14
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Wang Q, Sun L, Lu J, Ren ML, Zhang T, Huang Y, Zhou X, Sun Y, Zhang B, Chen C, Shen X, Agarwal R, Lu W. Emission energy, exciton dynamics and lasing properties of buckled CdS nanoribbons. Sci Rep 2016; 6:26607. [PMID: 27210303 PMCID: PMC4876404 DOI: 10.1038/srep26607] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Accepted: 05/05/2016] [Indexed: 11/09/2022] Open
Abstract
We report the modulation of emission energy, exciton dynamics and lasing properties in a single buckled CdS nanoribbon (NR) by strain-engineering. Inspired by ordered structure fabrication on elastomeric polymer, we develop a new method to fabricate uniform buckled NRs supported on polydimethylsiloxane (PDMS). Wavy structure, of which compressive and tensile strain periodically varied along the CdS NR, leads to a position-dependent emission energy shift as large as 14 nm in photoluminescence (PL) mapping. Both micro-PL and micro-reflectance reveal the spectral characteristics of broad emission of buckled NR, which can be understood by the discrepancy of strain-induced energy shift of A- and B-exciton of CdS. Furthermore, the dynamics of excitons under tensile strain are also investigated; we find that the B-exciton have much shorter lifetime than that of redshifted A-exciton. In addition, we also present the lasing of buckled CdS NRs, in which the strain-dominated mode selection in multi-mode laser and negligible mode shifts in single-mode laser are clearly observed. Our results show that the strained NRs may serve as new functional optical elements for flexible light emitter or on-chip all-optical devices.
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Affiliation(s)
- Qi Wang
- National Lab for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Science, Shanghai, 200083, China.,Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Liaoxin Sun
- National Lab for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Science, Shanghai, 200083, China
| | - Jian Lu
- Shanghai Advanced Research Institute, Chinese Academy of Science, Shanghai 201210, China
| | - Ming-Liang Ren
- Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania, 19104, United States
| | - Tianning Zhang
- National Lab for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Science, Shanghai, 200083, China
| | - Yan Huang
- National Lab for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Science, Shanghai, 200083, China
| | - Xiaohao Zhou
- National Lab for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Science, Shanghai, 200083, China
| | - Yan Sun
- National Lab for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Science, Shanghai, 200083, China
| | - Bo Zhang
- National Lab for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Science, Shanghai, 200083, China
| | - Changqing Chen
- Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Xuechu Shen
- National Lab for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Science, Shanghai, 200083, China
| | - Ritesh Agarwal
- Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania, 19104, United States
| | - Wei Lu
- National Lab for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Science, Shanghai, 200083, China
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15
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Zhang Y, Liu C, Liu J, Xiong J, Liu J, Zhang K, Liu Y, Peng M, Yu A, Zhang A, Zhang Y, Wang Z, Zhai J, Wang ZL. Lattice Strain Induced Remarkable Enhancement in Piezoelectric Performance of ZnO-Based Flexible Nanogenerators. ACS APPLIED MATERIALS & INTERFACES 2016; 8:1381-7. [PMID: 26704902 DOI: 10.1021/acsami.5b10345] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
In this work, by employing halogen elements (fluorine, chlorine, bromine, and iodine) as dopant we demonstrate a unique strategy to enhance the output performance of ZnO-based flexible piezoelectric nanogenerators. For a halogen-doped ZnO nanowire film, dopants and doping concentration dependent lattice strain along the ZnO c-axis are established and confirmed by the EDS, XRD, and HRTEM analysis. Although lattice strain induced charge separation was theoretically proposed, it has not been experimentally investigated for wurtzite structured ZnO nanomaterials. Tuning the lattice strain from compressive to tensile state along the ZnO c-axis can be achieved by a substitution of halogen dopant from fluorine to other halogen elements due to the ionic size difference between dopants and oxygen. With its focus on a group of nonmetal element induced lattice strain in ZnO-based nanomaterials, this work paves the way for enhancing the performance of wurtzite-type piezoelectric semiconductor nanomaterials via lattice strain strategy which can be employed to construct piezoelectric nanodevices with higher efficiency in a cost-effective manner.
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Affiliation(s)
- Yang Zhang
- Beijing Institute of Nanoenergy and Nanosystems, Chinese Academy of Sciences , Beijing 100083, China
| | - Caihong Liu
- Beijing Institute of Nanoenergy and Nanosystems, Chinese Academy of Sciences , Beijing 100083, China
| | - Jingbin Liu
- State Key Laboratory of Electronic Thin Films and Integrated Device, University of Electronic Science and Technology of China , Chengdu 610054, China
| | - Jie Xiong
- State Key Laboratory of Electronic Thin Films and Integrated Device, University of Electronic Science and Technology of China , Chengdu 610054, China
| | - Jingyu Liu
- Beijing Institute of Nanoenergy and Nanosystems, Chinese Academy of Sciences , Beijing 100083, China
| | - Ke Zhang
- Beijing Institute of Nanoenergy and Nanosystems, Chinese Academy of Sciences , Beijing 100083, China
| | - Yudong Liu
- Beijing Institute of Nanoenergy and Nanosystems, Chinese Academy of Sciences , Beijing 100083, China
| | - Mingzeng Peng
- Beijing Institute of Nanoenergy and Nanosystems, Chinese Academy of Sciences , Beijing 100083, China
| | - Aifang Yu
- Beijing Institute of Nanoenergy and Nanosystems, Chinese Academy of Sciences , Beijing 100083, China
| | - Aihua Zhang
- Beijing Institute of Nanoenergy and Nanosystems, Chinese Academy of Sciences , Beijing 100083, China
| | - Yan Zhang
- Beijing Institute of Nanoenergy and Nanosystems, Chinese Academy of Sciences , Beijing 100083, China
| | - Zhiwei Wang
- Beijing Institute of Nanoenergy and Nanosystems, Chinese Academy of Sciences , Beijing 100083, China
| | - Junyi Zhai
- Beijing Institute of Nanoenergy and Nanosystems, Chinese Academy of Sciences , Beijing 100083, China
| | - Zhong Lin Wang
- Beijing Institute of Nanoenergy and Nanosystems, Chinese Academy of Sciences , Beijing 100083, China
- School of Materials Science and Engineering, Georgia Institute of Technology , Atlanta, Georgia 30332-0245, United States
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16
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Fu X, Liao ZM, Liu R, Lin F, Xu J, Zhu R, Zhong W, Liu Y, Guo W, Yu D. Strain Loading Mode Dependent Bandgap Deformation Potential in ZnO Micro/Nanowires. ACS NANO 2015; 9:11960-11967. [PMID: 26517647 DOI: 10.1021/acsnano.5b04617] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The electronic-mechanical coupling in semiconductor nanostructures under different strain loading modes can modulate their photoelectric properties in different manners. Here, we report the systematic investigation on the strain mode dependent bandgap deformation potential of ZnO micro/nanowires under both uniaxial tensile and bending strains at room temperature. Uniaxial stretching-photoluminescence results show that the deformation potential of the smaller ZnO nanowire (with diameter d = 260 nm) is -30.6 meV/%, and is close to the bulk value, whereas it deviates the bulk value and becomes to be -10.6 meV/% when the wire diameter is increased to d = 2 μm. This unconventional size dependence stems from surface effect induced inhomogeneous strain in the surface layer and the core of the ZnO micro/nanowires under uniaxial tension. For bending load mode, the in situ high-resolution transmission electron microscope analysis reveals that the local strain distributes linearly in the bending cross section. Further cathodoluminescence measurements on a bending ZnO microwire (d = 1.8 μm) demonstrate that the deformation potential is -27 meV/%, whose absolute value is much larger than that of the ZnO microwire under uniaxial tension. Further analysis reveals that the distinct deformation potentials originate from the different deforming modes in ZnO micro/nanowires under bending or uniaxial tensile strains. Our results should facilitate the design of flexible optoelectronic nanodevices.
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Affiliation(s)
- Xuewen Fu
- State Key Laboratory for Mesoscopic Physics, Department of Physics, Peking University , Beijing 100871, P. R. China
| | - Zhi-Min Liao
- State Key Laboratory for Mesoscopic Physics, Department of Physics, Peking University , Beijing 100871, P. R. China
- Collaborative Innovation Center of Quantum Matter , Beijing 100871, P. R. China
| | - Ren Liu
- State Key Laboratory for Mesoscopic Physics, Department of Physics, Peking University , Beijing 100871, P. R. China
| | - Fang Lin
- State Key Laboratory for Mesoscopic Physics, Department of Physics, Peking University , Beijing 100871, P. R. China
| | - Jun Xu
- State Key Laboratory for Mesoscopic Physics, Department of Physics, Peking University , Beijing 100871, P. R. China
| | - Rui Zhu
- State Key Laboratory for Mesoscopic Physics, Department of Physics, Peking University , Beijing 100871, P. R. China
| | - Wei Zhong
- Key Laboratory of Yunnan Higher Education Institutes for Optoelectric Information &Technology , Kunming 650500, P. R. China
| | - Yingkai Liu
- Key Laboratory of Yunnan Higher Education Institutes for Optoelectric Information &Technology , Kunming 650500, P. R. China
| | - Wanlin Guo
- State Key Laboratory of Mechanics and Control of Mechanical Structures and Institute of Nano Science, Nanjing University of Aeronautics and Astronautics , 29 Yudao Street, Nanjing 210016, P. R. China
| | - Dapeng Yu
- State Key Laboratory for Mesoscopic Physics, Department of Physics, Peking University , Beijing 100871, P. R. China
- Collaborative Innovation Center of Quantum Matter , Beijing 100871, P. R. China
- Key Laboratory of Yunnan Higher Education Institutes for Optoelectric Information &Technology , Kunming 650500, P. R. China
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17
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Wang X, Yu R, Peng W, Wu W, Li S, Wang ZL. Temperature Dependence of the Piezotronic and Piezophototronic Effects in a-axis GaN Nanobelts. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2015; 27:8067-8074. [PMID: 26513637 DOI: 10.1002/adma.201504534] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Revised: 10/01/2015] [Indexed: 06/05/2023]
Abstract
The temperature dependence of the piezotronic and piezophototronic effects in a-axis GaN nanobelts from 77 to 300 K is investigated. The piezotronic effect is enhanced by over 440% under lower temp-eratures. Two independent processes are discovered to form a competing mechanism through the investigation of the temperature dependence of the piezophototronic effect in a-axis GaN nanobelts.
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Affiliation(s)
- Xingfu Wang
- School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA, 30332-0245, USA
- Guangdong Engineering Research Center of Optoelectronic Functional Materials and Devices, South China Normal University, Guangzhou, 510631, China
| | - Ruomeng Yu
- School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA, 30332-0245, USA
| | - Wenbo Peng
- School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA, 30332-0245, USA
| | - Wenzhuo Wu
- School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA, 30332-0245, USA
| | - Shuti Li
- Guangdong Engineering Research Center of Optoelectronic Functional Materials and Devices, South China Normal University, Guangzhou, 510631, China
| | - Zhong Lin Wang
- School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA, 30332-0245, USA
- Beijing Institute of Nanoenergy and Nanosystems, Chinese Academy of Sciences, Beijing, 100083, China
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18
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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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19
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Vempati S, Celebioglu A, Uyar T. Defect related emission versus intersystem crossing: blue emitting ZnO/graphene oxide quantum dots. NANOSCALE 2015; 7:16110-16118. [PMID: 26371542 DOI: 10.1039/c5nr04461h] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
In ref. [Nat. Nanotechnol., 2012, 7, 465-471] interesting optoelectronic properties of ZnO/graphene oxide (GO) composite were presented. Essentially, in the luminescence spectrum indirect optical transitions were identified to be from the epoxy group of GO (GOepoxy) to the valance band (Ev) of ZnO. Viz. 406 nm, L1: (LUMO+2)GOepoxy→Ev and 436 nm, L2: (LUMO)GOepoxy→Ev. Furthermore, the emission peak at ∼550 nm was attributed to zinc interstitials (Znis) or oxygen vacancies (VOs) and shown to span from 350-650 nm (equivalent to a width of ∼0.8 eV). In this report we accentuate two vital though largely ignored concerns as itemized in the following. (i) By considering the growth mechanism of ZnO in the composite, there is a certain possibility that these two bands (L1 and L2) may originate from intrinsic defects of ZnO such as Znis and extended Znis (ex-Znis). Or L1 and L2 might be intrinsic to GO. (ii) The 550 nm emission involves VOs and consists of two components with a typical width of ∼0.3 eV. Here we present the results of a thorough investigation confirming the presence of Znis, ex-Znis and intrinsic emission from GO. We also note that during the synthesis the presence of dimethyl formamide significantly affected the emission from GO in addition to some chemical modifications. Apart from these, we have discussed other crucial factors which require deeper attention in the context of luminescence from complex systems such as those present.
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Affiliation(s)
- Sesha Vempati
- UNAM-National Nanotechnology Research Centre, Bilkent University, Ankara, 06800, Turkey.
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20
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Watanabe K, Nagata T, Wakayama Y, Sekiguchi T, Erdélyi R, Volk J. Band-gap deformation potential and elasticity limit of semiconductor free-standing nanorods characterized in situ by scanning electron microscope-cathodoluminescence nanospectroscopy. ACS NANO 2015; 9:2989-3001. [PMID: 25689728 DOI: 10.1021/nn507159u] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Modern field-effect transistors or laser diodes take advantages of band-edge structures engineered by large uniaxial strain εzz, available up to an elasticity limit at a rate of band-gap deformation potential azz (= dEg/dεzz). However, contrary to aP values under hydrostatic pressure, there is no quantitative consensus on azz values under uniaxial tensile, compressive, and bending stress. This makes band-edge engineering inefficient. Here we propose SEM-cathodoluminescence nanospectroscopy under in situ nanomanipulation (Nanoprobe-CL). An apex of a c-axis-oriented free-standing ZnO nanorod (NR) is deflected by point-loading of bending stress, where local uniaxial strain (εcc = r/R) and its gradient across a NR (dεcc/dr = R(-1)) are controlled by a NR local curvature (R(-1)). The NR elasticity limit is evaluated sequentially (εcc = 0.04) from SEM observation of a NR bending deformation cycle. An electron beam is focused on several spots crossing a bent NR, and at each spot the local Eg is evaluated from near-band-edge CL emission energy. Uniaxial acc (= dEg/dεcc) is evaluated at regulated surface depth, and the impact of R(-1) on observed acc is investigated. The acc converges with -1.7 eV to the R(-1) = 0 limit, whereas it quenches with increasing R(-1), which is attributed to free-exciton drift under transversal band-gap gradient. Surface-sensitive CL measurements suggest that a discrepancy from bulk acc = -4 eV may originate from strain relaxation at the side surface under uniaxial stress. The nanoprobe-CL technique reveals an Eg(εij) response to specific strain tensor εij (i, j = x, y, z) and strain-gradient effects on a minority carrier population, enabling simulations and strain-dependent measurements of nanodevices with various structures.
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Affiliation(s)
- Kentaro Watanabe
- †WPI Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan
- ‡Faculty of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8571, Japan
| | - Takahiro Nagata
- †WPI Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan
| | - Yutaka Wakayama
- †WPI Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan
| | - Takashi Sekiguchi
- †WPI Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan
| | - Róbert Erdélyi
- §MTA EK Institute of Technical Physics and Materials Science, Konkoly Thege M. út 29-33, 1121 Budapest, Hungary
| | - János Volk
- §MTA EK Institute of Technical Physics and Materials Science, Konkoly Thege M. út 29-33, 1121 Budapest, Hungary
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21
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Zhang K, Qi J, Tian Y, Lu S, Liang Q, Zhang Y. Influence of piezoelectric effect on dissolving behavior and stability of ZnO micro/nanowires in solution. RSC Adv 2015. [DOI: 10.1039/c4ra12659a] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
We demonstrate for the first time the corrosion behavior of ZnO micro/nanowires under stress, investigating the influence of the piezoelectric effect on the corrosion of ZnO micro/nanowires in acidic and alkaline environments.
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Affiliation(s)
- Kui Zhang
- School of Materials Science and Engineering
- University of Science and Technology Beijing
- Beijing 100083
- People’s Republic of China
| | - Junjie Qi
- School of Materials Science and Engineering
- University of Science and Technology Beijing
- Beijing 100083
- People’s Republic of China
| | - Yuan Tian
- School of Materials Science and Engineering
- University of Science and Technology Beijing
- Beijing 100083
- People’s Republic of China
| | - Shengnan Lu
- School of Materials Science and Engineering
- University of Science and Technology Beijing
- Beijing 100083
- People’s Republic of China
| | - Qijie Liang
- School of Materials Science and Engineering
- University of Science and Technology Beijing
- Beijing 100083
- People’s Republic of China
| | - Yue Zhang
- School of Materials Science and Engineering
- University of Science and Technology Beijing
- Beijing 100083
- People’s Republic of China
- Key Laboratory of New Energy Materials and Technologies
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22
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Grumstrup EM, Gabriel MM, Pinion CW, Parker JK, Cahoon JF, Papanikolas JM. Reversible strain-induced electron-hole recombination in silicon nanowires observed with femtosecond pump-probe microscopy. NANO LETTERS 2014; 14:6287-6292. [PMID: 25259929 DOI: 10.1021/nl5026166] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Strain-induced changes to the electronic structure of nanoscale materials provide a promising avenue for expanding the optoelectronic functionality of semiconductor nanostructures in device applications. Here we use pump-probe microscopy with femtosecond temporal resolution and submicron spatial resolution to characterize charge-carrier recombination and transport dynamics in silicon nanowires (NWs) locally strained by bending deformation. The electron-hole recombination rate increases with strain for values above a threshold of ∼1% and, in highly strained (∼5%) regions of the NW, increases 6-fold. The changes in recombination rate are independent of NW diameter and reversible upon reduction of the applied strain, indicating the effect originates from alterations to the NW bulk electronic structure rather than introduction of defects. The results highlight the strong relationship between strain, electronic structure, and charge-carrier dynamics in low-dimensional semiconductor systems, and we anticipate the results will assist the development of strain-enabled optoelectronic devices with indirect-bandgap materials such as silicon.
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Affiliation(s)
- Erik M Grumstrup
- Department of Chemistry, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599, United States
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23
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Iqbal D, Kostka A, Bashir A, Sarfraz A, Chen Y, Wieck AD, Erbe A. Sequential growth of zinc oxide nanorod arrays at room temperature via a corrosion process: application in visible light photocatalysis. ACS APPLIED MATERIALS & INTERFACES 2014; 6:18728-34. [PMID: 25278370 DOI: 10.1021/am504299v] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Many photocatalyst systems catalyze chemical reactions under ultraviolet (UV) illumination, because of its high photon energies. Activating inexpensive, widely available materials as photocatalyst using the intense visible part of the solar spectrum is more challenging. Here, nanorod arrays of the wide-band-gap semiconductor zinc oxide have been shown to act as photocatalysts for the aerobic photo-oxidation of organic dye Methyl Orange under illumination with red light, which is normally accessible only to narrow-band semiconductors. The homogeneous, 800-1000-nm-thick ZnO nanorod arrays show substantial light absorption (absorbances >1) throughout the visible spectral range. This absorption is caused by defect levels inside the band gap. Multiple scattering processes by the rods make the nanorods appear black. The dominantly crystalline ZnO nanorod structures grow in the (0001) direction, i.e., with the c-axis perpendicular to the surface of polycrystalline zinc. The room-temperature preparation route relies on controlled cathodic delamination of a weakly bound polymer coating from metallic zinc, an industrially produced and cheaply available substrate. Cathodic delamination is a sequential synthesis process, because it involves the propagation of a delamination front over the base material. Consequently, arbitrarily large sample surfaces can be nanostructured using this approach.
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Affiliation(s)
- Danish Iqbal
- Center for Electrochemical Sciences (CES), Ruhr-Universität Bochum , 44801 Bochum, Germany
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24
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Fu X, Su C, Fu Q, Zhu X, Zhu R, Liu C, Liao Z, Xu J, Guo W, Feng J, Li J, Yu D. Tailoring exciton dynamics by elastic strain-gradient in semiconductors. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2014; 26:2572-2579. [PMID: 24470383 DOI: 10.1002/adma.201305058] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2013] [Revised: 11/08/2013] [Indexed: 06/03/2023]
Abstract
In purely bent ZnO microwires, the excitons can be effectively driven and concentrated by the elastic strain-gradient towards the tensile outer side of the purely bent wire. Experimental and theoretical approaches are combined to investigate the dynamics of excitons in an inhomogeneous strain field with a uniform elastic strain-gradient. Cathodoluminescence spectroscopy analysis on purely bent ZnO microwires verifies that excitons can be effectively driven and concentrated along the elastic strain-gradient.
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Affiliation(s)
- Xuewen Fu
- State Key Laboratory for Mesoscopic Physics and Electron Microscopy Laboratory, School of Physics, Peking University, and Collaborative Innovation Center of Quantum Matter, Beijing, 100871, China
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25
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Fu X, Jacopin G, Shahmohammadi M, Liu R, Benameur M, Ganière JD, Feng J, Guo W, Liao ZM, Deveaud B, Yu D. Exciton drift in semiconductors under uniform strain gradients: application to bent ZnO microwires. ACS NANO 2014; 8:3412-20. [PMID: 24654837 DOI: 10.1021/nn4062353] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Optimizing the electronic structures and carrier dynamics in semiconductors at atomic scale is an essential issue for innovative device applications. Besides the traditional chemical doping and the use of homo/heterostructures, elastic strain has been proposed as a promising possibility. Here, we report on the direct observation of the dynamics of exciton transport in a ZnO microwire under pure elastic bending deformation, by using cathodoluminescence with high temporal, spatial, and energy resolutions. We demonstrate that excitons can be effectively drifted by the strain gradient in inhomogeneous strain fields. Our observations are well reproduced by a drift-diffusion model taking into account the strain gradient and allow us to deduce an exciton mobility of 1400 ± 100 cm(2)/(eV s) in the ZnO wire. These results propose a way to tune the exciton dynamics in semiconductors and imply the possible role of strain gradient in optoelectronic and sensing nano/microdevices.
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Affiliation(s)
- Xuewen Fu
- State Key Laboratory for Mesoscopic Physics, and Electron Microscopy Laboratory, Department of Physics, Peking University , 209 Chengfu Road, Beijing 100871, China
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26
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Fu X, Liao Z, Yu D. Electronic and Mechanical Coupling in Elastically Bent ZnO Micro/Nanowires. ACTA ACUST UNITED AC 2014. [DOI: 10.1557/opl.2014.324] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
ABSTRACTElastic engineering strain has been regarded as a low-cost and continuously variable manner for altering the physical and chemical properties of materials, and it becomes even more important at low-dimensionality because at micro/nanoscale, materials/structures can usually bear exceptionally high elastic strains before failure. The elastic strain effects are therefore greatly magnified in micro/nanoscale structures and should be of great potential in the design of novel functional devices. The purpose of this overview is to present a summary of our recently progress in the energy band engineering of elastically bent ZnO micro/nanowires. First, we present the electronic and mechanical coupling effect in bent ZnO nanowires. Second, we summary the bending strain gradient effect on the near-band-edge (NBE) emission photon energy of bent ZnO micro/nanowires. Third, we show that the strain can induce exciton fine-structure splitting and shift in ZnO microwires. Our recent progresses illustrate that the electronic band structure of ZnO micro/nanowires can be dramatically tuned by elastic strain engineering, and point to potential future applications based on the elastic strain engineering of ZnO micro/nanowires.
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27
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Wei B, Ji Y, Han XD, Zhang Z, Zou J. Variation of exciton emissions of ZnO whiskers reversibly tuned by axial tensile strain. OPTICS EXPRESS 2014; 22:4000-4005. [PMID: 24663721 DOI: 10.1364/oe.22.004000] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Applying strain on semiconductors is a powerful method to modulate its electronic structures and optical properties. In this study, the behavior of liquid-nitrogen exciton emissions and the longitudinal optical phonon-exciton interactions of tensile strained [0001]-orientated ZnO whiskers were investigated using in situ cathodoluminescence spectroscopy. It has been found that, under the axial tensile strain, various exciton emissions shift to the long wavelength and their shifts have a linear relationship with the applied strain. This linear relationship and reversible shift suggest that the strain plays a dominating role in manipulating light emissions of axially strained ZnO whiskers.
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28
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Li P, Liao Q, Yang S, Bai X, Huang Y, Yan X, Zhang Z, Liu S, Lin P, Kang Z, Zhang Y. In situ transmission electron microscopy investigation on fatigue behavior of single ZnO wires under high-cycle strain. NANO LETTERS 2014; 14:480-485. [PMID: 24382199 DOI: 10.1021/nl403426c] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The fatigue behavior of ZnO nanowires (NWs) and microwires was systematically investigated with in situ transmission electron microscopy electromechanical resonance method. The elastic modulus and mechanical quality factors of ZnO wires were obtained. No damage or failure was found in the intact ZnO wires after resonance for about 10(8)-10(9) cycles, while the damaged ZnO NW under electron beam (e-beam) irradiation fractured after resonance for seconds. The research results will provide a useful guide for designing, fabricating, and optimizing electromechanical nanodevices based on ZnO nanomaterials, as well as future applications.
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Affiliation(s)
- Peifeng Li
- State Key Laboratory for Advanced Metals and Materials, School of Materials Science and Engineering, Key Laboratory of New Energy Materials and Technologies, University of Science and Technology Beijing , Beijing 100083, People's Republic of China
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Yang Q, Wu Y, Liu Y, Pan C, Wang ZL. Features of the piezo-phototronic effect on optoelectronic devices based on wurtzite semiconductor nanowires. Phys Chem Chem Phys 2014; 16:2790-800. [PMID: 24402437 DOI: 10.1039/c3cp53737d] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The piezo-phototronic effect, a three way coupling effect of piezoelectric, semiconductor and photonic properties in non-central symmetric semiconductor materials, utilizing the piezo-potential as a "gate" voltage to tune the charge transport/generation/recombination and modulate the performance of optoelectronic devices, has formed a new field and attracted lots of interest recently. The mechanism was verified in various optoelectronic devices such as light emitting diodes (LEDs), photodetectors and solar cells etc. The fast development and dramatic increasing interest in the piezo-phototronic field not only demonstrate the way the piezo-phototronic effects work, but also indicate the strong need for further research in the physical mechanism and potential applications. Furthermore, it is important to distinguish the contribution of the piezo-phototronic effect from other factors induced by external strain such as piezoresistance, band shifting or contact area change, which also affect the carrier behaviour and device performance. In this perspective, we review our recent progress on piezo-phototronics and especially focus on pointing out the features of piezo-phototronic effect in four aspects: I-V characteristics; c-axis orientation; influence of illumination; and modulation of carrier behaviour. Finally we proposed several criteria for describing the contribution made by the piezo-phototronic effect to the performance of optoelectronic devices. This systematic analysis and comparison will not only help give an in-depth understanding of the piezo-phototronic effect, but also work as guide for the design of devices in related areas.
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Affiliation(s)
- Qing Yang
- School of Material Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0245, USA.
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Abstract
Abstract
Technology advancement that can provide new solutions and enable augmented capabilities to complementary metal–oxide–semiconductor (CMOS)-based technology, such as active and adaptive interaction between machine and human/ambient, is highly desired. Piezotronic nanodevices and integrated systems exhibit potential in achieving these application goals. Utilizing the gating effect of piezopotential over carrier behaviors in piezoelectric semiconductor materials under externally applied deformation, the piezoelectric and semiconducting properties together with optoelectronic excitation processes can be coupled in these materials for the investigation of novel fundamental physics and the implementation of unprecedented applications. Piezopotential is created by the strain-induced ionic polarization in the piezoelectric semiconducting crystal. Piezotronics deal with the devices fabricated using the piezopotential as a ‘gate’ voltage to tune/control charge-carrier transport across the metal–semiconductor contact or the p–n junction. Piezo-phototronics is to use the piezopotential for controlling the carrier generation, transport, separation and/or recombination for improving the performance of optoelectronic devices. This review intends to provide an overview of the rapid progress in the emerging fields of piezotronics and piezo-phototronics. The concepts and results presented in this review show promises for implementing novel nano-electromechanical devices and integrating with micro/nano-electromechanical system technology to achieve augmented functionalities to the state-of-the-art CMOS technology that may find applications in the human–machine interfacing, active flexible/stretchable electronics, sensing, energy harvesting, biomedical diagnosis/therapy, and prosthetics.
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Affiliation(s)
- Zhong Lin Wang
- School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA 30332-0245, USA
- Beijing Institute of Nanoenergy and Nanosystems, Chinese Academy of Sciences, Beijing 100083, China
| | - Wenzhuo Wu
- School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA 30332-0245, USA
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Park JB, Hong WK, Bae TS, Sohn JI, Cha S, Kim JM, Yoon J, Lee T. Strain effects in a single ZnO microwire with wavy configurations. NANOTECHNOLOGY 2013; 24:455703. [PMID: 24140605 DOI: 10.1088/0957-4484/24/45/455703] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
We investigate strain-induced optical modulation in a ZnO microwire with wavy geometries induced by mechanical strains. Curved sections of the wavy ZnO microwire show red-/blue-shifts of near-band-edge emission and broadening of full width at half maximum in cathodoluminescence spectra along the length of the wavy ZnO microwire, compared with straight sections. The observed variations indicate that local strains in the wavy ZnO microwire lead to strain-dependent local changes of its energy band structure. The local bending curvature calculations using a geometric model also provide correlation between the shift of the near-band-edge emission peaks and the bending strain.
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Affiliation(s)
- Jong Bae Park
- Jeonju Center, Korea Basic Science Institute, Jeonju, Jeollabuk-do 561-180, Korea. Department of Engineering Science, University of Oxford, Oxford OX1 3PJ, UK
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Fu XW, Liao ZM, Liu R, Xu J, Yu D. Size-dependent correlations between strain and phonon frequency in individual ZnO nanowires. ACS NANO 2013; 7:8891-8. [PMID: 24047124 DOI: 10.1021/nn403378g] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
The effect of uniaxial tensile strain on individual ZnO nanowires with diameters ranging from 500 nm to 2.7 μm and the effect of pure bending strain on ZnO microwires are systematically investigated by Raman spectroscopy. It is found for the first time that the tensile and compressive strains result in a linear downshift and upshift of the phonon frequencies of the E2L, E2H, E1TO, and second-order modes compared with the strain-free state, respectively, while the A1TO mode is not influenced by the strain. Furthermore, the strain modulation on phonons depends strongly on the nanowire diameter. The E2H phonon deformation potential is ~3 cm(-1)/% for the 500 nm nanowire, while 1% tensile strain results only in ~1 cm(-1) downward frequency shift for the 2.7 μm ZnO wire. The results provide a versatile "local-self-calibration" and nondestructive method to measure and monitor the local strains in ZnO micro/nanostructures.
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Affiliation(s)
- Xue-Wen Fu
- State Key Laboratory for Mesoscopic Physics, Department of Physics, Peking University , Beijing 100871, People's Republic of China
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Liu R, Fu XW, Meng J, Bie YQ, Yu DP, Liao ZM. Graphene plasmon enhanced photoluminescence in ZnO microwires. NANOSCALE 2013; 5:5294-8. [PMID: 23695346 DOI: 10.1039/c3nr01226c] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
We report the temperature dependent photoluminescence (PL) properties of monolayer graphene-Au-nanoparticle-ZnO (GAZ) microwire hybrid structures. By comparing with the bare ZnO wire without coverage of graphene, a three times enhancement of PL was found in the GAZ hybrid structures. The enhancement is attributed to the coupling between the PL photons from ZnO and the graphene surface plasmons with ~1-2 nm Au as a corrugated surface. Our results may be valuable for designing graphene-ZnO hybrid based optical and photoelectrical devices.
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Affiliation(s)
- Ren Liu
- State Key Laboratory for Mesoscopic Physics, Department of Physics, Peking University, Beijing 100871, PR China
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