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Volumn 3, Issue 12, 2003, Pages 1625-1631

Spontaneous Polarization-Induced Nanohelixes, Nanosprings, and Nanorings of Piezoelectric Nanobelts

Author keywords

[No Author keywords available]

Indexed keywords

ARTICLE; CRYSTAL; ELASTICITY; ENERGY; NANOTECHNOLOGY; PIEZOELECTRICITY; POLARIZATION; SENSOR; SURFACE PROPERTY; THICKNESS; TRANSDUCER;

EID: 0346101516     PISSN: 15306984     EISSN: None     Source Type: Journal    
DOI: 10.1021/nl034463p     Document Type: Article
Times cited : (1163)

References (41)
  • 2
    • 0348022819 scopus 로고    scopus 로고
    • See the special issue on transparent conducting oxides
    • See the special issue on transparent conducting oxides, MRS Bulletin, August issue, 2000.
    • (2000) MRS Bulletin , Issue.AUGUST ISSUE
  • 25
    • 0347392027 scopus 로고    scopus 로고
    • Patent pending, Georgia Tech, 2003
    • Wang, Z. L.; Kong, X. Y. Patent pending, Georgia Tech, 2003.
    • Wang, Z.L.1    Kong, X.Y.2
  • 27
    • 0348022817 scopus 로고    scopus 로고
    • note
    • The as-synthesized samples were characterized by field emission source scanning electron microscopy (SEM) (LEO 1530 FEG at 5 kV), high-resolution transmission electron microscopy (HRTEM) (Hitachi HF-2000 FEG at 200 kV and JEOL 4000EX at 400 kV).
  • 29
    • 0003464779 scopus 로고
    • Plenum Press: New York
    • The polarity of ZnO results in asymmetric intensity distribution in the (0002) and (0002̄) diffraction disks. The polarity was determined by comparing the experimentally observed convergent beam electron diffraction pattern with the theoretically calculated diffraction pattern. Details of the calculation can be found in Spence, J. C. H.; Zuo, J. M. Electron Microdiffraction; Plenum Press: New York, 1992.
    • (1992) Electron Microdiffraction
    • Spence, J.C.H.1    Zuo, J.M.2
  • 30
    • 0348022818 scopus 로고    scopus 로고
    • note
    • The local deposition temperature is ∼400-500°C, which is high enough to prevent physical adsorption of molecules on the surface during the growth. Thus, the ionic charges on the surface are likely uncompensated and are electrostatically effective for producing the helical structure.
  • 31
    • 0347392025 scopus 로고    scopus 로고
    • note
    • The calculation was made based on following approximations: [1] the thickness of the nanobelt is much smaller than the radius of the nanoring (t ≪: R); [2] the width (W) of the nanobelt is significantly larger than its thickness, so that the edge effect is small. However, it is the difference between the electrostatic energy before and after rolling into a cylinder that matters to the final result; if the edge effect before and after rolling is preserved, the edge effect, if any, is almost canceled out in the final equation. [3] The surface charges are due to the unique crystallographic structure of ZnO, and they are bound to the atoms, thus, the surface charge density is preserved after rolling into a cylinder. Therefore, the total charge on the inner surface of the cylinder is Q = 2π(R - t/2)Wσo. The change in electrostatic energy is (Formula Presented) (for t ≪ R) where β = t/2R.
  • 32
    • 0347392026 scopus 로고    scopus 로고
    • note
    • Because the thickness of the nanobelt is very small and the ring radius is large, the radial stress across the nanobelt is negligible because the two sides are free surfaces without external force. The strain along the z-direction (the axis of the cylinder) is also zero because there is no twisting. The only strain is along the φ-direction. The elastic energy is the volume integration of the φ-direction strain energy. The bending modulus used for the calculation was based on the experimentally measured value for ZnO nanobelts with inclusion of geometrical factor.
  • 40
    • 0346131097 scopus 로고    scopus 로고
    • note
    • In-situ heating of the helical nanostructure has been carried out in TEM under vacuum of 10-8 Torr. Heating the specimen to 400°C generated a high concentration of oxygen vacancies based our previous study in ref. 19, but no visible change in the shape of the helical nanostructure was found, suggesting that the role played by point defects in the formation of helical structure is undetectable.
  • 41
    • 0346761744 scopus 로고    scopus 로고
    • note
    • Thanks the support from NSF and NASA URETI. Thanks to Profs. Min Zhou and Ashok Saxena for discussion.


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.