教師著作

Permanent URI for this collectionhttp://rportal.lib.ntnu.edu.tw/handle/20.500.12235/31266

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    Effects of doping concentration and annealing temperature on properties of highly-oriented Al-doped ZnO films
    (Elsevier, 2006-01-18) Kuo, Shou-Yi; Chen, Wei-Chun; Lai, Fang-I; Cheng, Chin-Pao; Kuo, Hao-Chung; Wang, Shing-Chung; Hsieh, Wen-Feng
    Transparent and conductive high-preferential c-axis-oriented Al-doped zinc oxide (ZnO:Al, AZO) thin films have been prepared by the sol–gel route. Film deposition was performed by spin-coating technique on Si(1 0 0) and glass substrate. Structural, electrical and optical properties were performed by XRD, SEM, four-point probe, photoluminescence (PL) and UV-VIS spectrum measurements. The effects of annealing temperature and dopant concentration on the structural and optical properties are well discussed. It was found that both annealing temperature and doping concentration alter the microstructures of AZO films. Also, PL spectra show two main peaks centered at about 380 nm (UV) and 520 nm (green). The variation of UV-to-green band emission was greatly influenced by annealing temperatures and doping concentration. Reduction in intensity ratio of UV-to-green might possibly originate from the formation of Al–O bonds and localized Al-impurity states. The minimum sheet resistance of 104 Ω/□ was obtained for the film doped with 1.6 mol% Al, annealed at 750 °C. Meanwhile, all AZO films deposited on glass are very transparent, between 80% and 95% transmittance, within the visible wavelength region. These results imply that the doping concentration did not have significant influence on transparent properties, but improve the electrical conductivity and diversify emission features.
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    Investigation of Annealing-treatment on the Optical and Electrical Properties of Sol-Gel-Derived Zinc Oxide Thin Films
    (2005-05-31) Chen, Wei-Chun; Cheng, Chin-Pao; Kuo, Shou-Yi
    Highly preferential c-axis orientation ZnO thin films on Si(100) and quartz substrates have been achieved by sol-gel method. Structural investigation including surface morphology and microstructure was carried out by XRD, SEM and AFM measurements. Also, optical properties were determined by photoluminescence, ellipsometry and UV-VIS spectrum analyses. XRD results indicated that an extremely sharp (002) peak will dominate under optimum annealing-treatment condition. Moreover, thin film quality and the morphology were improved by annealing treatment. The SEM images show that the grains sizes increased with increasing annealing temperature up to 750 oC, where the particle size was about 50 nm. Photoluminescence spectra revealed two main peaks centered at about 380 nm and 520 nm, corresponding to the band-edge and defect-related emission. The variation in UV emission intensity was attributed to the competition between the excitonic and nonradiative recombination. It was proposed that annealing temperature plays a key role in the formation of defects, which is strongly related to the nonradiative recombination centers. In addition, optical transmittance spectra demonstrated that these films are very transparent (~90%) in the range of 380-800 nm wavelength, and optical band-gap was determined accordingly. The impact of the thermal treatment on the structural and optical properties was discussed in detail.
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    Investigation of annealing-treatment on the optical and electrical properties of sol–gel-derived zinc oxide thin films
    (Elsevier, 2005-08-01) Kuo, Shou-Yi; Chen, Wei-Chun; Cheng, Chin-Pao
    Highly preferential c-axis orientation ZnO thin films on Si(100) and quartz substrates have been achieved by the sol–gel method. Structural investigation including surface morphology and microstructure was carried out by XRD, SEM and AFM measurements. Also, optical properties were determined by photoluminescence, ellipsometry and UV–VIS spectrum analyses. XRD results indicated that an extremely sharp (002) peak will dominate under optimum annealing-treatment condition. Moreover, thin film quality and the morphology were improved by annealing treatment. The SEM images show that the grain sizes increased with increasing annealing temperature up to 750 ring operatorC, where the particle size was about 50 nm. Photoluminescence spectra revealed two main peaks centered at about 380 nm and 520 nm, corresponding to the band-edge and defect-related emission. The variation in UV emission intensity was attributed to the competition between the excitonic and nonradiative recombination. It was proposed that annealing temperature plays a key role in the formation of defects, which is strongly related to the nonradiative recombination centers. In addition, optical transmittance spectra demonstrated that these films are very transparent (not, vert, similar90%) in the range of 380–800 nm wavelength, and optical band-gap was determined accordingly. The impact of the thermal treatment on the structural and optical properties was discussed in detail.
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    Observation of ultraviolet lasing from polycrystalline zno films
    (2005-07-11) Kuo, Shou-Yi; Chen, Wei-Chun; Lai, Fang–I; Cheng, Chin-Pao; Kuo, Hao-Chung; Wang, Shing-Chung
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    Ultraviolet Lasing of Sol–Gel-Derived Zinc Oxide Polycrystalline Films
    (Japan Society of Applied Physics, 2006-04-25) Kuo, Shou-Yi; Chen, Wei-Chun; Lai, Fang-I; Cheng, Chin-Pao; Kuo, Hao-Chung; Wang, Shing-Chung
    The effect of post-annealing on sol–gel-derived ZnO films has been investigated. For these films, structural investigations including analyses of surface morphology and microstructures were carried out by X-ray diffraction (XRD), scanning electron microscopy (SEM) and atomic force microscopy (AFM). Also, optical properties were determined by photoluminescence analysis, ellipsometry and optical pumping measurement. The XRD results indicate that the (002) peak will predominate with increasing annealing temperature. SEM images show that grain size increased with annealing temperature. Moreover, photoluminescence spectra revealed the enhancement in UV emission intensity with annealing temperature, which was attributed to an improvement in crystal quality. Room-temperature ultraviolet random lasing action was observed in the ZnO films. The threshold intensity for the lasing was estimated to be ∼70 kW/cm2. Furthermore, it was found that the formation of random laser action is affected by post-annealing, which is associated to the presence of a high-gain medium and efficient light scattering.