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ZnO Nanotubes (zno + nanotube)

Distribution by Scientific Domains
Polymers and Materials Science50%
Physics and Astronomy50%

Selected Abstracts

Fabrication and Optical Characteristics of Position-Controlled ZnO Nanotubes and ZnO/Zn0.8Mg0.2O Coaxial Nanotube Quantum Structure Arrays

ADVANCED FUNCTIONAL MATERIALS, Issue 10 2009
Jinkyoung Yoo
Abstract The position-controlled growth and structural and optical characteristics of ZnO nanotubes and their coaxial heterostructures are reported. To control both the shape and position of ZnO nanotubes, hole-patterned SiO2 growth-mask layers on Si(111) substrates with GaN/AlN intermediate layers using conventional lithography are prepared. ZnO nanotubes are grown only on the hole patterns at 600,°C by catalyst-free metal,organic vapor-phase epitaxy. Furthermore, the position-controlled nanotube growth method allows the fabrication of artificial arrays of ZnO-based coaxial nanotube single-quantum-well structures (SQWs) on Si substrates. In situ heteroepitaxial growth of ZnO and Zn0.8Mg0.2O layers along the circumference of the ZnO nanotube enable an artificial formation of quantum-well arrays in a designed fashion. The structural and optical characteristics of the ZnO nanotubes and SQW arrays are also investigated using synchrotron radiation X-ray diffractometry and photoluminescence and cathodoluminescence spectroscopy. [source]

Optical properties of ZnO nanotubes

CRYSTAL RESEARCH AND TECHNOLOGY, Issue 6 2010
Hongju Zhai
Abstract Tubular ZnO nanostructures have been obtained via a hydrothermal method at low temperature (90 °C) without any catalysts or templates. The XRD measurement reveals that the tubes are single crystals with hexagonal wurtzite structure. SEM shows that the diameters of ZnO nanotubes ranged from 400 to 550 nm. The Raman and PL spectra indicate that oxygen vacancies or Zn interstitials are responsible for the green emission in the ZnO nanotubes. A possible growth mechanism on the formation of crystalline ZnO nanotubes has been presented. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Fabrication and Optical Characteristics of Position-Controlled ZnO Nanotubes and ZnO/Zn0.8Mg0.2O Coaxial Nanotube Quantum Structure Arrays

ADVANCED FUNCTIONAL MATERIALS, Issue 10 2009
Jinkyoung Yoo
Abstract The position-controlled growth and structural and optical characteristics of ZnO nanotubes and their coaxial heterostructures are reported. To control both the shape and position of ZnO nanotubes, hole-patterned SiO2 growth-mask layers on Si(111) substrates with GaN/AlN intermediate layers using conventional lithography are prepared. ZnO nanotubes are grown only on the hole patterns at 600,°C by catalyst-free metal,organic vapor-phase epitaxy. Furthermore, the position-controlled nanotube growth method allows the fabrication of artificial arrays of ZnO-based coaxial nanotube single-quantum-well structures (SQWs) on Si substrates. In situ heteroepitaxial growth of ZnO and Zn0.8Mg0.2O layers along the circumference of the ZnO nanotube enable an artificial formation of quantum-well arrays in a designed fashion. The structural and optical characteristics of the ZnO nanotubes and SQW arrays are also investigated using synchrotron radiation X-ray diffractometry and photoluminescence and cathodoluminescence spectroscopy. [source]

High-Sensitivity Solid-State Pb(Core)/ZnO(Shell) Nanothermometers Fabricated by a Facile Galvanic Displacement Method,

ADVANCED MATERIALS, Issue 24 2008
Chiu-Yen Wang
Solid-Pb-filled ZnO nanotubes are synthesized and tested for use as nanothermometers. The expansion of the filling with increasing temperature (see figure) , or the corresponding changes in capacitance , can be measured and related to temperature. The advantages of this nanothermometer are extremely low fabrication costs, superior reliability, and lower demands on structural integrity of the outer shell compared to nanothermometers based on liquid fillings. [source]

Synthesis of Aligned Arrays of Ultrathin ZnO Nanotubes on a Si Wafer Coated with a Thin ZnO Film,

ADVANCED MATERIALS, Issue 20 2005
Y. Sun
Aligned arrays of ultrathin, high-quality ZnO nanotubes (see Figure) have been synthesized via hydrothermal growth methods on Si that has been pre-coated with a thin film of ZnO. The nanorods are single-crystalline, with typical wall thicknesses and outer diameters of 5,15 and 20,40,nm, respectively. Annealing the arrays in vacuum causes enhancement of UV photoluminescence. [source]

Current-transport studies and trap extraction of hydrothermally grown ZnO nanotubes using gold Schottky diode

PHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 3 2010
G. Amin
Abstract High-quality zinc oxide (ZnO) nanotubes (NTs) were grown by the hydrothermal technique on n-Si substrate. The room temperature (RT) current-transport mechanisms of Au Schottky diodes fabricated from ZnO NTs and nanorods (NRs) reference samples have been studied and compared. The tunneling mechanisms via deep-level states was found to be the main conduction process at low applied voltage but at the trap-filled limit voltage (VTFL) all traps were filled and the space-charge-limited current conduction was the dominating current-transport mechanism. The deep-level trap energy and the trap concentration for the NTs were obtained as ,0.27,eV and 2.1,×,1016,cm,3, respectively. The same parameters were also extracted for the ZnO NRs. The deep-level states observed crossponds to zinc interstitials (Zni), which are responsible for the violet emission. [source]