Characterization of Nanomaterials

Studies of Electronic Excitations in Nano-Materials by Spatially Resolved Electron Energy Loss Spectroscopy [ 下載 PDF ]

Chien-Ting Wu

The electronic excitations of nano-materials are investigated by spatially resolved electron energy loss spectroscopy and energy dispersive X-ray spectrometer used in conjunction with scanning transmission electron microscopy (STEM-EELS/EDS) in order to further study the microstructure, physical and chemical properties. When fast electrons pass through the materials, they will generate various solid state excitations with bulk and surface characteristics via Coulomb interactions and lose energies accordingly. Typical bulk excitations include bulk plasmons (BPs), Cherenkov radiations, band gap and inter band transitions and inner-shell ionizations. Surface excitations with propagation wavevector confined along the surface include surface plasmons (SPs), surface guided mode and surface exciton polaritons (SEPs). These excitations play a very important role in the properties of materials.

Influences of Electrode Junctions on Scanning Capacitance Microscopy [ 下載 PDF ]

Mao-Nan Chang, Tsung-Yu Chan, Jhih-Yang Chen, Yung-Han Chuang

In this article, we introduce the influences of electrode junctions on scanning capacitance microscopy (SCM). Differential capacitance signals of scanning capacitance microscopy are very sensitive to the electrode junctions of an SCM specimen. For the contact point of the conductive probe, UV illumination reduced defects of the native oxide layer on sample surface and obviously enhanced the signal intensity of SCM. For the image analysis of a specimen with P-N junctions, the sample electrode setup is very important to the contrast and the accuracy of differential capacitance images. The sample electrode contact with both n- and p-type regions provides reliable differential capacitance images.

Metabolism of TiO₂ Nano-Particles in NIH-3T3 Cells Using Atomic Force Microscopy [ 下載 PDF ]

Ya-Chi Huang, Pin-Siou Huang, Mon-Shu Ho

This study compared the effects of 3–5 nm and 10–30 nm TiO₂ nanoparticles after exposing to NIH-3T3 cells over a span of 7 days. we observed that TiO₂ nanoparticles, of both sizes, are toxic to cells. Both sizes of nanoparticles show cell growth inhibition in which the inhibitory effects of 3–5 nm TiO₂ nanoparticles were more significant. Comparative effects of mechanical properties on the cell, and around in which 3–5 nm TiO₂ nanoparticles were added, through AFM, showed height variation in the cell nucleus where the nucleus expanded and cell adhesion changed with increasing number of days. The nucleus and cell synapses adhesion were seen to have significantly increased as well, while adhesion force of the cell periphery showed a decline, this showed that cytoskeletal damage caused softening of the cell structure were cause after having being exposed to TiO₂ nanoparticles.

Direct Observation of Atoms [ 下載 PDF ]

Chien-Nan Hsiao

A progress of the atomic resolution microstructure characterization has been brief described by means of the microstructure characterizations of phase transformation of alloy steel, bionics materials, optical thin films, nanocatalyst and semiconductor epitaxial materials. The development and principle of optical microscopy, scanning electron microscopy, transmission electron microscopy and aberration-corrected scanning transmission electron microscopy were illustrated.

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Novel Thread-Based Microfluidic Systems for Bioanalytical Applications [ 下載 PDF ]

Che-Wei Lin, Che-Hsin Lin

For the past decade, the applications of Bio-MEMS grow exponentially in various fields including medical detection, food detection, agriculture and other industrials. Over the developed bio-chip devices, capillary electrophoresis (CE) chip is one of the most promising schemes since it is capable of separating and detecting the target bio-samples in the microfluidic system. In general, silicon wafer, glass, polydimethylsiloxane (PDMS), polymethylmethacrylate (PMMA), Teflon are used as the substrate materials for bioanalytical detections. This study developed a novel thread-based microfluidic system capable of capillary electrophoresis separation, sample electrochemical detection, and even electrospray ionization. The developed thread-based microfl uidic system is used to detect the blood urea nitrogen (BUN) and glucose (GLU) in human serum. The system can also be integrated with mass-spectrometry detection of natural products such as food ingredients. The thread-based microfluidic system developed in the present study provides a low-cost yet high performance was for analyzing biosamples or food samples.

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Photoluminescence Enhancement of Monolayer MoSe₂ by Hydrohalic Acid Treatment [ 下載 PDF ]

Hau-Vei Han, Hao-Chung Kuo [Translate]

Atomically thin two-dimensional transition-metal di-chalcogenides (TMDCs) have attracted much attention due to their unique electronic and optical properties for future optoelectronic devices. Although there are many promising fabrication processes have been employed to produce high quality TMDCs layers with a scalable size and a controllable thickness, the grown TMDC monolayers may still incorporate unwanted structural defects. These defects significantly trap free charge carriers and localize excitons, leading to the smearing of free band-toband exciton emission. In this paper, we introduce a simple hydrohalic acid treatment to efficiently suppress the trap state emission and promote the neutral exciton and trion emission in defective MoSe₂ monolayers. The overall photoluminescence intensity at room temperature can be enhanced by a factor of 30. Our results suggest that the hydrohalic acid treatment not only reduces the structural defects, but also modifies the corresponding optoelectronic characteristics in fabricated MoSe₂ layers, providing further insights of the control and tailoring the exciton emission from monolayer TMDCs.

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Multi-Channel Polarization State Generator and Analyzer [ 下載 PDF ]

Chun-Jen Weng, Da-Ren Liu, Shian-Wen Chang, Chi-Hung Hwang

This work proposes a creative filter wheel with only one precision motor for multi-channel polarization state switching. Any polarization states can be easily switched and orientated by this apparatus for the polarmetric characteristic.

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A Point-of-Care Device Communication Controller System Based on IEEE 11073 PoCD Standards [ 下載 PDF ]

Yuan-Fa Lee

With the rapid growth of Information and Communication Technology (ICT) and the transition of hospital care manpower and manner, bedside medical device with communication ability becomes important functionality. Current researches focus on personal health-care medical devices that adopt internal medical device communication standards. But, these researches do not discuss the hospital requirements. There are many differences between the personal health-care device and the point-of-care device. For example, use cases, patient conditions, environment, communication interface, and real-time data upload requirement. In addition, for point-of-care patient monitor in hospital, we need to concern how to reduce staff loading and human error, and the benefit of the analysis and statistics of vital sign data for healthcare providers. The design for the PoCD communications controller system proposed in this paper is based on the ISO/IEEE 11073 Point-of-Care Device (PoCD) communication standards. The PoCD communications controller system connects to the Philips IntelliVue series patient monitor through Ethernet. When the Philips IntelliVue patient monitor senses the physical activities from the users, and then transmits these data to the PoCD communications controller system in compliance with IEEE 11073 PoCD data format and protocol standards via the Ethernet interface. Based on the testing results, users can transmit measurement data to the PoCD communications controller system over the Ethernet interface successfully.