Applications of Micro/Nano Technology

Drug Screening System by Microcantilever Biochip [ 下載 PDF ]

Chih-Wei Wu

Taiwan, located in the subtropical region, is one of the major epidemic areas of Japanese encephalitis, dengue fever and enterovirus. There is still no effective drug or vaccine that can truly cure the mentioned-above infectious diseases until now. It is the first priority to understand the infection processes of the viruses in order to find effective antiviral drugs or vaccines. Most traditional methods have to use large equipments located in the laboratory to detect or analyse virus. Although they have accurate detection abilities, but also have many disadvantages like long detection time, large volume of samples and reagents, non-real time, expensive cost. This study has proposed a novel system to record completed infection processes of Japanese encephalitis, dengue fever and enterovirus. Meanwhile, the inhibiting ability of antibody or antiviral drug has studied also by the same system. The system is consisted of a biochip manufactured by MEMS technology, optical measurement platform, and biocompatible hydrogel material. The biochip size is 3.15 × 3.15 cm which is consisted of microcantilever beams with hydrogel and a PDMS microfluidic. The biochip successfully recorded infection processes of different viruses in different concentrations. It was found that Japanese encephalitis had obvious penetration, replication and separation stages. Furthermore, dengue fever virus, which is the same genus as Japanese encephalitis, had a similar infection process. In view of the detection results, for each of the virus mentioned above, the effective specific antibody and the ineffective non-specific antibody were respectively injected into the biochips along with the virus. The antivirus ability of the antibodies was verified within few hours. The tedious work and the time cost by traditional immunoassay were avoided. In addition, the antiviral drug, algae extract, was proved that it could inhibit dengue fever virus for few hours. This study had proved that the biochip and detection system could successfully record completed infection processes for different virus and drug screen. It is believed that the experiment results described above are helpful for drug screen, functional food, and vaccine discovery.

Investigation of InN Epilayer Grown on Ga-face GaN by RF-CBE [ 下載 PDF ]

Wei-Chun Chen, Jr-Sheng Tian, Yue-Han Wu, Shou-Yi Kuo, Fang-I Lai, Chien-Nan Hsiao, Li Chang

Indium nitride is a III-V semiconductor which is potential for optoelectronics and electronics application due to its high electron mobility, high peak drift velocity, low effective electron mass and narrow bandgap of 0.65–0.7 eV. InN has been grown using metalorganic chemical vapor deposition (MOCVD) and molecular beam epitaxy (MBE). It has been known that InN has a low dissociation temperature at 600 °C, such that the growth temperature is limited by the desorption of nitrogen and the thermal decomposition of the films. Therefore, the high-quality InN is usually obtained by using MBE. Various processing parameters may affect the quality of InN, such as substrate, buffer layer, substrate temperature, pressure, and V/III flow ratio. In this study, polar and semipolar InN films were prepared by plasma-assisted metal-organic molecular beam epitaxy (PA-MOMBE) which can have a high growth rate. Detailed characterizations of structural and optical properties of the grown polar InN films were carried out. The results indicated that In-polar InN films grown with the V/III ratio of ~1.81 has the smallest full width at half maximum (FWHM) value of 455 arcsec for (0002) X-ray rocking curve (XRC) andFWHMs value of 1070 arcsec for (1012). The epitaxial relationship of InN with GaN substrate is (0002)_InN//(0002)_GaN and [1120]_InN//[1120]_GaN as determined by selected area electron diffraction. Additionally, the InN growth rate decreases from 1.9 to 1.4 µm/h when the ratio increases from 1.81 to 4.

Development and Application of Atomic Layer Deposition [ 下載 PDF ]

Chung-Ting Ko, Miin-Jang Chen

Atomic layer deposition (ALD) is one of the most important semiconductor processes for deposition of nanoscale ultrathin films. ALD offers many benefits, including precise thickness control with monolayer accuracy, high uniformity over a large area, and excellent step coverage (conformality) on nonplanar high-aspect-ratio structures. Hence ALD plays the important role in 300 mm silicon manufacturing technology and fin field-effect transistors (FinFET). This article will introduce the principle of the ALD technique. Based on many years of experience in the ALD technique, the key factors such as the ALD mechanism and the design of the ALD equipment which have significant impact on the thin film deposition will be discussed. In addition, we also describe the increasingly important ALD metal processes, and share the experience in the ALD processes of platinum and silver. Finally, the application of ALD on the nanoplasmonics will also be introduced in this article.

Thermoelectric Microgenerators with Carbon Nanotubes [ 下載 PDF ]

Chun-Chia Yeh, Ming-Zhi Yang, Ching-Liang Dai

The thermoelectric microgenerators are manufactured using the standard complementary metal oxide semiconductor (CMOS) process. The microgenerators are composed of 370 thermocouples in series, and the thermocouples are formed by p-type and n-type polysilicon. The efficiency of the generators depends on the temperature difference between hot and cold parts of thermocouples. To enhance the generation efficiency, the reactive ion etching is employed to release the suspended structure of hot part, and the carbon nanotubes (CNTs) are coated on the hot part. The cold part of the thermocouples is covered by silicon oxide that provides low thermal conductivity and thermal isolation. ANSYS is adopted to simulate the temperature distribution and gradient of the generators. The experimental results showed that the thermoelectric generators without CNTs film had an output voltage of 0.90 mV and an output power of 1.72 pW at 400 K. The output voltage and output power of the generators with CNTs film were 1.56 mV and 5.16 pW at 400 K, respectively. The thermoelectric power generator with the MCNTs film had a voltage factor of 0.23 mV/K/mm² and a power factor of 0.75 pW/K/mm².

Characterization of Three Dimensional Split Ring Resonators Fabricated by Stress-Driven Self-Assembly Method [ 下載 PDF ]

Che-Chin Chen, Yu-Hsiang Tang, Ming-Hua Shiao, Din Ping Tsai

The split ring resonator is one of the most important meta-atom for constructing the artificial photonic metamaterials. For higher frequency applications, the most difficult part is to fabricate the three-dimensional structures. In this study, we demonstrate a simple strategy by utilizing metal-stress self-assembly method to fabricate infrared three-dimensional split ring resonators. This strategy is simply involved lithography and dry etching processes. The electromagnetic properties are characterized through both spectrum experiments and numerical simulations.

Application of Nanomaterial TiO₂ for the Gaseous HCHO Sensing [ 下載 PDF ]

Ren-Jang Wu, Hsiao-Fang Lai, Chung-Yun Cheng

In this study, homemade nano-titania TiO₂, Au/TiO₂ and Pd/TiO₂ were prepared as sensing materials, and using X-ray diffraction (X-ray diffraction, XRD) and transmission electron microscopy (transmission electron microscope, TEM) instrument to characterize the materials. The purpose is to understand its microstructure and sensing properties of HCHO gas. Research items are including sensor response, response time, recovery time and repeatability test. We found that the addition of Au and Pd on TiO₂ can promote the sensor response of TiO₂ about three times, and reduce the response time and recovery time. A sensing mechanism was proposed in this study. It can be expected in the future academic innovation and practicality developed the new materials with high sensitivity of formaldehyde gas sensing technology.

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The Theoretical Model of the Collinear Holographic Data Storage System [ 下載 PDF ]

Chih-Yuan Cheng, Yeh-Wei Yu, Ching-Cherng Sun

The holographic data storage possesses ultra-high capacity and two-dimensional access technology. It is regarded as the most promising storage technology in the next generation. Based on VOHIL and scalar diffraction theory, we construct the theoretical model of the collinear holographic data storage system. According to the theoretical model, we derive the paraxial solution, which can help us to grasp the physical characteristics and propose the best solution. First, we discuss the effects of the distribution of the reference patterns on the point spread function and the shift selectivity in this paper. Then, we add the phase modulation in the reference pattern. It facilitates the lower power of the laser light source and miniaturization of the system. What’s more, it decreases the half width of the point spread function. By adding more bits within per page, we enhance the capacity and accessing speed synchronously.

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Development of Optical Resolution Photoacoustic Micro-imaging System for Micro-vasculature Imaging [ 下載 PDF ]

Bin-Han Sun, Meng-Lin Li

Blood vessels play an important role in many significant disease researches such as cancer study. In this study, we developed an unfocused ultrasound transducer based optical resolution photoacoustic micro-imaging system (OR-PAM) for in vivo micro-vasculature imaging of small animals. Photoacoustic imaging is a novel bioimaging modality based on the photoacoustic effect. For micro-vasculature imaging, it owns the advantages of label free high optical absorption contrast and can be performed non-invasively. It also can provide blood-related functional imaging capability for the measure of total hemoglobin concentration and hemoglobin oxygen saturation. Conventional OR-PAM employs a focused ultrasound transducer to improve the signal-to-noise ratio (SNR) and performs mechanical scanning for imaging. However, mechanical scanning is time-consuming. Such a problem can be solved by optical scanning while the optical objective lens and focused ultrasound transducer limit the field of view (FOV) instead. In our design, the FOV is improved by using an unfocused ultrasound transducer. In addition, based on the spatial impulse response of the unfocused transducer, the center frequency, size, and imaging distance of the unfocused ultrasound transducer are optimized to improve the SNR. The experimental results showed that the spatial resolution of the developed OR-PAM was 13.5 µm in the en-face imaging plane. In vivo micro-vascular imaging capability was also demonstrated. Future work will focus on the improvement of the imaging frame rate and spatial resolution and the development of multi-wavelength functional micro-vascular imaging.