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Kaohsiung, Taiwan

Hu S.-Y.,Tungfang Design Institute | Chou W.-C.,National Chiao Tung University | Weng Y.-H.,National Taiwan Ocean University
Journal of Alloys and Compounds | Year: 2015

Ternary alloys of ZnMgO samples with different magnesium contents have been grown by molecular beam epitaxy on the sapphire substrates. Room temperature photoluminescence energy of ZnMgO shifted as high as 3.677 eV by increasing Mg contents corresponding to the higher Urbach average localization energy which indicates more randomness in the alloys with higher Mg contents. XRD results are also verified that the c-axis length decreases as the increasing Mg contents linking to the increased tensile stress produced by the Mg atoms. Raman spectra analyzed by the spatial correlation model to describe that the linewidth Γ is decreased but the correlation length L is increased as the increasing of Mg contents. © 2015 Elsevier B.V. Source


Chen C.-I.,I - Shou University | Huang S.-J.,Tungfang Design Institute
Proceedings of 2013 4th International Asia Conference on Industrial Engineering and Management Innovation, IEMI 2013 | Year: 2014

Grey theory is popular formany years. GM(1,1) is the most used model in grey theory. In the model, there are two coefficients a and b which are determined by lease square method. Base on our research result, the grey development coefficient a should not be zero. If it is, the prediction result is totally erroneous. The correct way to solve this problem is to adopt L'Hôpital Rule. In this paper, we also demonstrate how nonlinear grey Bernoulli model could avoid the appearance the singular situation and increase the prediction precision. © 2014 Springer-Verlag Berlin Heidelberg.. Source


Chen N.,Tungfang Design Institute | Tzeng C.-T.,National Cheng Kung University | Tsay Y.,National Cheng Kung University | Chen C.,National Cheng Kung University
Indoor Air 2014 - 13th International Conference on Indoor Air Quality and Climate | Year: 2014

Aiming at the hot and humid climatic conditions in southern Taiwan, this study discusses the terminologies of buildings, namely the impact of balcony on natural ventilation and indoor temperature, and probes into two vertical air guide designs (general and ventilated) of balcony, as well as reviews the impact of balcony depth. The research methods include field measurement and numerical simulation. The findings show that the air guide balcony of this study can be adopted for small depth, and the balcony with vertical air deflector design is recommended for large depth, not only increasing indoor air velocity, but also improving the warming phenomenon resulted from the increase of balcony depth. Source


Wu T.Y.,National Taiwan Ocean University | Huang Y.S.,National Taiwan Ocean University | Hu S.Y.,Tungfang Design Institute | Lee Y.C.,Tungnan University | And 4 more authors.
Solid State Communications | Year: 2016

We have investigated the luminescence characteristics of Zn1-xCdxO thin films with different Cd contents grown by molecular beam epitaxy system. The temperature-dependent photoluminescence (PL) and excitation power-dependent PL spectra were measured to clarify the luminescence mechanisms of the Zn1-xCdxO thin films. The peak energy of the Zn1-xCdxO thin films with increasing the Cd concentration is observed as redshift and can be fitted by the quadratic function of alloy content. The broadened full-width at half-maximum (FWHM) estimated from the 15 K PL spectra as a function of Cd content shows a larger deviation between the experimental values and theoretical curve, which indicates that experimental FWHM values are affected not only by alloy compositional disorder but also by localized excitons occupying states in the tail of the density of states. The Urbach energy determined from an analysis of the lineshape of the low-energy side of the PL spectrum and the degree of localization effect estimated from the temperature-induced S-shaped PL peak position described an increasing mean exciton-localization effects in ZnCdO films with increasing the Cd content. In addition, the PL intensity and peak position as a function of excitation power are carried out to clarify the types of radiative recombination and the effects of localized exciton in the ZnCdO films with different Cd contents. © 2016 Elsevier Ltd. All rights reserved. Source


Cheng F.J.,Tungnan University | Lee Y.C.,Tungnan University | Hu S.Y.,Tungfang Design Institute | Lin Y.C.,National Taiwan Ocean University | And 2 more authors.
IOP Conference Series: Materials Science and Engineering | Year: 2016

In this work, the carrier dynamics in Zn1-xCdxO thin films with different Cd contents grown by molecular beam epitaxy system have been investigated using photoluminescence and time-resolved photoluminescence measurements. The carrier lifetime can be estimated from the PL decay curve fitted by triple exponential function. The emission energy dependence and temperature dependence of the PL decay time indicate that carrier localization dominate the luminescence mechanism of the ZnCdO alloy semiconductor. © Published under licence by IOP Publishing Ltd. Source

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