Browsing by Author "Kuo, Wan-Lin"

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Synthesis and luminescent properties of strong blue light-emitting Al2O3/ZnO nanocables
(2008)
Hsiao, Chi-Sheng
;
Kuo, Wan-Lin
;
Chen, San-Yuan
;
Shen, Ji-Lin
;
Lin, Chin-Ching
Photoelectronic characteristics are investigated in well-aligned aluminum-coated ZnO nanorods (Al2O3/ZnO nanocables) grown on Si substrates buffered with ZnO film at a low temperature. Photoluminescence measurement indicates that a strong blue emission peak at similar to 450 nm appears at 400 and 600 degrees C in O-2 and N-2 atmospheres, respectively. A 30x enhancement of the relative intensity ratio of blue emission (I-B) to ultraviolet emission (I-UV) has been observed for the Al2O3/ZnO nanocables. High-resolution transmission electron microscopy and X-ray photoelectron spectroscopy analyses reveal that the origin of the strong blue emission can be attributed to the structure transition and cleavage of the oxygen-hydrogen bond (OH) of the Al2O3/ZnO nanocable, which leads to the formation of singly ionized oxygen vacancies (Al-O-center dot). (C) 2008 The Electrochemical Society.
Synthesis and optical properties of white-light-emitting alumina/ZnO nanotubes
(2008-10-08)
Hsiao, Chi-Sheng
;
Chen, San-Yuan
;
Kuo, Wan-Lin
;
Lin, Chin-Ching
;
Cheng, Syh-Yuh
A simple chemical solution process was used to prepare alumina nanoparticle-coated ZnO nanotubes (ANZTs). Transmission electron microscope (TEM) images proved that the alumina nanoparticles were uniformly dispersed on the ZnO nanotubes. After thermal treatment at different temperatures under various atmospheres, photoluminescence (PL) measurements showed that the ANZTs emitted a variety of colors, including blue, green and white light. Gaussian curve fitting of the PL spectra revealed that the competition between the blue, blue-green, green and yellow band emissions and their relative emission intensities were strongly associated with various defects. Blue emission was attributed to large numbers of oxygen defects in alumina, while green and yellow emissions were related to oxygen and zinc defects in ZnO, respectively. Under specific conditions, white light, consisting of blue, blue-green, green and yellow band emissions, was obtained. Further TEM analysis indicated that the defect structure of ANZTs could be manipulated by the interface interaction between alumina and the ZnO nanotubes.