Browsing by Author "Lo, Shen-Chuan"

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A study on fabrication, morphological and optical properties of lead sulfide nanocrystals
(2008-02-01)
Chen, Jung-Hsuan
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Lo, Shen-Chuan
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Chao, Chuen-Guang
;
Liu, Tzeng-Feng
;
材料科學與工程學系
To investigate the properties of lead sulfide (PbS) nanocrystals, we have prepared PbS nanocrystals on/in the porous alumina membrane with a pore diameter 20 nm. Utilizing the reaction of Pb wires and the hydrogen sulfide (H2S) gas, PbS nanocrystals produced and grew as the reaction time increased. The composition identification of the nanocrystals was performed by the XPS and EDS analyses. More structure characteristics of the PbS nanocrystals obtained from the TEM analysis. As indicated in the PL spectra, an orange-red emission band appeared and the emission intensities were obviously related to the defects in the nanocrytals. A significant quantum confinement effect made the energy gap of PbS nanocrystals produce a blue shift from 0.41 eV to 1.89 eV. Furthermore, the growth mechanism of the PbS nanocrystals was also discussed.
Gate-All-Around Single-Crystal-Like Poly-Si Nanowire TFTs With a Steep-Subthreshold Slope
(2013-04-01)
Liu, Tung-Yu
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Lo, Shen-Chuan
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Sheu, Jeng-Tzong
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材料科學與工程學系
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Department of Materials Science and Engineering
We investigate the characteristics of single-crystallike (SCL) poly-Si nanowire (SCL poly-Si NW) thin-film-transistors with gate-all-around (GAA) structures. The GAA SCL poly-Si NWs are prepared by a modified sidewall spacer process utilizing an amorphous silicon (alpha-Si) mesa structure. The combination of the high surface-to-volume ratio of the NW and a nominal gate length of 0.25 mu m lead to clear improvement in electrical performance, including a steep subthreshold swing (90 +/- 15 mV/dec), a virtual absence of drain-induced barrier lowering (21 +/- 13 mV/V), and a very high ON/OFF current ratio similar to 7 x 10(7) (V-D = 1 V, V-G = 3 V).
Microstructure and properties of Pb nanowires fabricated by casting
(2008-06-01)
Chen, Jung-Hsuan
;
Lo, Shen-Chuan
;
Chao, Chuen-Guang
;
Liu, Tzeng-Feng
;
材料科學與工程學系
In this study, we fabricated Pb nanowires in porous alumina membranes with different diameters by pressure casting. It can produce a large quantity of Ph nanowires with average diameters of 20, 80, 200, and 300 nm and lengths of up to 10 Pm. The diameter and length of the nanowires can be controlled by selecting templates with a desired size. The microstructure and size effects of Ph wires on the solidification process were investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction analysis (XRD), and thermal analysis. The nanowires with average diameters of 20 and 80 nm were single crystals, but those with average diameters of 200 and 300 nm were polycrystals. Finally, we also discussed the melting behaviors of the Pb nanowires in the porous alumina matrix.
Multifunctional silver nanocluster-hybrid oligonucleotide vehicle for cell imaging and microRNA-targeted gene silencing
(2017-04-01)
Chen, Hau-Yun
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Albert, Karunya
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Wen, Cheng-Che
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Hsieh, Pei-Ying
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Chen, Sih-Yu
Novel therapeutics is urgently needed to prevent cancer-related deaths. MicroRNAs that act as tumor suppressors have been recognized as a next-generation tumor therapy, and the restoration of tumor suppressive microRNAs using microRNA replacements or mimics may be a less toxic, more effective strategy due to fewer off-target effects. Here, we designed the novel multifunctional oligonucleotide nanocarrier complex composed of a tumor-targeting aptamer sequence specific to mucin 1. (MUC1), poly-cytosine region for fluorescent silver nanocluster (AgNC) synthesis, and complimentary sequence for microRNA miR-34a loading. MiR-34a was employed because of its therapeutic effect of inhibiting oncogene expression and inducing apoptosis in carcinomas. By monitoring the intrinsic fluorescence of AgNC, it was clearly shown that the constructed complex (MUC1-AgNCm-miR-34a) enters MCF-7 cells. To evaluate the efficacy of this nanocarrier for microRNA delivery, we investigated the gene and protein expression levels of downstream miR-34a targets (BCL-2, CDK6, and CCNDI) by quantitative PCR and western blotting, respectively, and the results indicated their effective inhibition by miR-34a. This novel multifunctional AgNC-based nanocarrier can aid in improving the efficacy of breast cancer theranostics. (C) 2017 Elsevier B.V. All rights reserved.
Multiple heterostructures of Ni2Si/Si formed by the point contact reaction
(2009)
Hao Ouyang
;
Cheng, Ming-Ting
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Shiu, Yung-Ruei
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Lo, Shen-Chuan
;
Wu, Wen-Wei
The high quality multiple heterostructures of Ni2Si/Si in a nanowire of Si can be formed by using the point contact reaction between several Ni nanodots and a Si nanowire carried out in-situ in an ultrahigh vacuum transmission electron microscopy. The fabricated multi-nano-heterostructures may enhance the development of circuit elements in nano-scale electronic devices. The unusual tetragonal Ni2Si (I4/mcm) phase rather than the commonly observed HCP Ni2Si (P63/m) was identified in the multiple heterostructures of Ni2Si/Si with the existence of surface oxide. The corresponding electronic structure and kinetic paths of phase transformations will be simulated and discussed.
Transparent Antiradiative Ferroelectric Heterostructure Based on Flexible Oxide Heteroepitaxy
(2018-09-12)
Ma, Chun-Hao
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Jiang, Jie
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Shao, Pao-Wen
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Peng, Qiang-Xiang
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Huang, Chun-Wei
In the era of Internet of Things, the demand for flexible and transparent electronic devices has shifted to the forefront of materials science research. However, the radiation damage to key performance of transparent devices under radiative environment remains as a critical issue. Here, we present a promising technology for nonvolatile transparent electronic devices based on flexible oxide heteroepitaxy. A direct fabrication of epitaxial lead lanthanum zirconate titanate on transparent flexible mica substrate with indium tin oxide electrodes is presented. The transparent flexible ferroelectric heterostructures not only retain their superior performance, thermal stability, reliability, and mechanical durability, but also exhibit remarkably robust properties against to a strong radiation exposure. Our study demonstrates an extraordinary concept to realize transparent flexible nonvolatile electronic devices for the design and development of next-generation smart devices with potential application in electronics, automotive, aerospace, and nuclear systems.
Valence state map of iron oxide thin film obtained from electron spectroscopy imaging series
(2007)
Chen, Ko-Feng
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Lo, Shen-Chuan
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Chang, Li
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Egerton, Ray
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Kai, Ji-Jung
This paper demonstrates the applicability of electron-spectroscopic imaging (ESI) for valence-state mapping of the iron oxide system. We have previously developed a set of signal-processing methods for an EST series, to allow mapping Of sp(2)/sp(3) ratio, dielectric function and energy bandgap. In this study, these methods are applied to generate a valence-state map of an iron oxide thin film (Fe/alpha-Fe2O3). Two problems, data undersampling and a convolution effect associated with extraction of the image-spectrum from the core loss image series, were overcome by using cubic-polynomial interpolation and maximum-entropy deconvolution. As a result, the reconstructed image-spectrum obtained from the EST series images has a quality as good as that of conventional electron energy-loss spectra. The L-3/L-2 ratio of the reconstructed EST spectrum is determined to be 3.30 +/- 0.30 and 5.0 +/- 0.30 for Fe and alpha-Fe2O3, respectively. Our L-3/L-2, ratio mapping shows an accurate correspondence across the Cu/Fe/alpha-Fe2O3 region. The effect of delocalization and chromatic aberration on the EST resolution is discussed and estimated to be about 2 nm for the case of L-3/L-2, ratio mapping. (c) 2006 Published by Elsevier Ltd.