Hong C.-S.,National Kaohsiung Normal University |
Chu S.-Y.,National Cheng Kung University |
Chu S.-Y.,Institute of Nanotechnology and Microsystems Engineering |
Chu S.-Y.,Center for Micro Nano Science and Technology |
And 3 more authors.
Journal of Applied Physics | Year: 2011
Two different methods, the conventional direct oxide synthesized method and the two-step indirect synthesized (IS) method, were employed to synthesize the 0.75Pb (Fe2/3W1/3)O3-0.25 PbTiO3 ceramics. The low-field dielectric responses were investigated using the empirical law and the Curie-Weiss law. The temperature-dependent local ordering parameters were derived from the experimental results using the spin-glass model and the modified-Landau theory separately. According to the experimental data and the fitting results, it is concluded that the temperature-dependent local order parameters are changed from a short-range-ordered relaxor to a long-range-ordered ferroelectric state using the IS method. On the basis of the physical concepts of the spin-glass model, the modified-Landau theory and the ordering models, it is suggested that local polarizations are affected not only by degree of ordering but also by space charge polarization. In contrast, the glassy behavior of local polarization is affected only by degree of ordering but has nothing to do with space charge polarization. It is because local fields induced by space charge polarization have the same effect on local polarizations and are neutralized when calculating the correlation between neighboring polar microregions. On the other hand, the freezing process of local polarizations is affected by both degree of ordering and space charge polarization because local polarization affected by local fields cannot be neutralized when calculating the individual behavior of local polarization. © 2011 American Institute of Physics.
Chen K.J.,Institute of Microelectronics |
Hung F.Y.,Institute of Nanotechnology and Microsystems Engineering |
Chang S.J.,Institute of Microelectronics |
Hu Z.S.,National Cheng Kung University
Journal of the Electrochemical Society | Year: 2010
ZnO nanowires were successfully prepared on a silica glass substrate using the sol-gel method. The ZnO nanowires grew from ZnO grains or ZnO grain boundaries, and the length increased with an increment in crystallized temperature. Diffused zinc ions combined with injected oxygen and gradually formed the ZnO nanowires. According to the diffusion mechanism and the law of conservation of mass, the bottom film of ZnO decreased but ZnO nanowires grew. The 650°C film not only possessed better crystallization, but also had the efficacy of nanowires that enhanced optical characteristics. © 2010 The Electrochemical Society.
Hsueh H.T.,Institute of Nanotechnology and Microsystems Engineering |
Hsueh T.J.,National Nano Device Laboratories |
Chang S.J.,Institute of Nanotechnology and Microsystems Engineering |
Chang S.J.,National Cheng Kung University |
And 6 more authors.
Electrochemical and Solid-State Letters | Year: 2010
High density silicon nanowires (SiNWs) were selectively grown on a Cr/glass template with a very thin 5 nm thick a-Si:H layer at 500°C by a vapor-liquid-solid process using Au-Si nanoparticles as catalysts. SiNWs cannot be grown without the a-Si:H layer. Field emitters using these SiNWs were also fabricated. The threshold field of the fabricated field emitters was 15 V/μm. Furthermore, the field enhancement factor, Β, of the fabricated SiNW field emitter was around 1700. © 2010 The Electrochemical Society.
Hsieh Y.-T.,Institute of Nanotechnology and Microsystems Engineering |
2012 7th IEEE International Conference on Nano/Micro Engineered and Molecular Systems, NEMS 2012 | Year: 2012
This paper reports a novel process which is combine the contact metal transfer method and traditional photolithography process for fabricate nano-scale pattern sapphire substrate (NPSS) used in high brightness light emitting diodes (LEDs). The novel process can directly transfer a metal pattern onto the PR layer which above the sapphire substrate, the transferred metal pattern can as a perfect photo-mask for subsequent photolithography process. In this work, the high aspect ratio PR structures with the aspect ratio of 5 and line width of 500 nm are created by this novel process. Furthermore, the PR structure can as a etching mask for inductively coupled plasma (ICP) etching on the sapphire substrate. During the ICP etching, we successfully to obtain the NPSS with a perfect cone shape. Experiments have been demonstrate the feasibility of using this new approach for obtaining sub-micrometer surface structures on the complete surface area of a 2 inch and 4 inch sapphire substrates. © 2012 IEEE.