2010.8
About Instruments Today No. 177
Nano Inspection and Applications
Development and Applications of High-Sensitivity Scanning Capacitance Microscopy [ 下載 PDF ]
Mao-Nan Chang, Chih-Chao Huang, Feng-Tso Chien
Scanning capacitance microscopy (SCM) can directly provide electrical properties of materials by detecting and imaging the differential capacitance signals on a material surface. In addition to the applications on the observations of carrier concentration distribution and electrical junctions, there are many extended applications for special topics. However, with the quick development of device processes SCM has also faced challenges such as high sensitivity, high spatial resolution and quantitative analysis. More and more experimental evidences suggested that it is possible to enhance both sensitivity and spatial resolution. Recently, experimental results indicated that high-sensitivity SCM can be applied to observe and to investigate not only the tiny variations of carrier concentration but also dopant activation behaviors in depth. In this article, we introduce the factors influencing the signal sensitivity of SCM, including system structure, experimental environment, specimen preparation and conductive probes. It is expected that the information provided in this article is helpful and useful for both academic and industrial fields.
Lensless Coherent Diffractive Imaging [ 下載 PDF ]
Roman Dronyak, Hsin-Yu Tang, Fu-Rong Chen, Keng-San Liang
Recent advances in high-resolution transmission electron microscopy were of most popular in the field of phase problem, correction of electromagnetic lens aberrations, and three-dimensional atomic tomography. The phase restoration and elimination of lens aberrations could be achieved simultaneously by applying coherent diffractive imaging (CDI) technique in electron microscopy. High resolution image (sub-Å) could be obtained by Fourier transform of high frequency signal from reciprocal space. The aberration-free 3-dimentional structure can be reconstructed from a series of diffraction patterns. The phase of exit wave can be retrieved from diffraction pattern by applying HIO algorithm. Although the method of coherent electron diffractive imaging remains under development, we have successfully performed a detailed investigation of the electron CDI restoring the 3-dimentional structure of MgO nanocrystals and the electron exit wave.
In Situ Imaging of Magnetization Reversal Process in Circular Patterned Magnetic Thin Film [ 下載 PDF ]
Cheng-Yi Kuo, Jong-Ching Wu
Due to practical potentials and applications on magnetic recording, field sensors and spin transistor, the magnetic domain structures of patterned magnetic thin films have been intensively investigated in the past decade or also. Magnetic force microscopy (MFM) is one of the commonly used techniques for detecting magnetization configuration in magnetic thin film, where MFM images the intensity variation of the field strayed from the sample surface. Thus, the stray field intensity sensed by the sharp magnetic probe is then displayed in bright and dark contrast. Herein, we introduce this MFM technique especially in the aspect of imaging the domain structures of disk- and ring-shaped magnetic thin films in-situ under an external magnetic field applied in the film plane. Notice that the magnetization of circular shape magnetic film orientates along the edges at remanent state to perform a flux closure domain, which is due to the shape effect. Consequently, there is no contrast on the MFM image except the vortex core in the central area of the disk shaped magnetic film. By applying an external magnetic field the magnetization configuration will start to evolve, thus the domain structures are successfully observed in high spatial resolution. This dynamic investigation of the magnetization reversal in the magnetic thin films may provide very useful information in designing the aforementioned devices.
Observation of Human Erythrocyte with Atomic Force Microscopy [ 下載 PDF ]
Feng-jia Ku, Chung-Jen Chen, Yu-Siang Lee, Mon-Shu Ho
In this article, the nano-mechanical characteristics of the cell membrane and cytoskeleton of human erythrocytes were studied using atomic force microscopy (AFM). The self assembly, fine structure, cell diameter, thickness and reticulate cytoskeleton of erythrocytes on bio-compatible surfaces, such as Mica and PDMS, were investigated. The adhesive forces that correspond to the membrane elasticity of various parts of the erythrocyte membrane surface were measured directly by AFM. The deformation of erythrocytes was discussed. A comparison between methods of biochemical engineering and biophysics were discussed in this work. Liquid physiological conditions were considered throughout. Moreover, the ability of the AFM to image surfaces with resolution down to the nanometer scales were demonstrated in applications ranging from physics to cell biology. Finally we believe that this important approach and technology development will make significant contributions to the advancement of biomedical test.
Fabrication of Silicon Nanopillar Arrays for the Electrodes in Fuel Cell [ 下載 PDF ]
Yu-Hsiang Tang, Mao-Jung Huang, Chii-Rong Yang, Ming-Hua Shiao
This research will integrate self-assembled nanosphere lithography (SANL) and photo-assisted electrochemical etching (PAECE) techniques for fabricating perfect and high regular arrangement of the nanopillars array structure. In addition, we fabricate the electrodes applied in the direct methanol fuel cell by means of these techniques. Experimental results show that the nanosphere array with a nearly perfect arrangement can be obtained in the sample area of 2 × 2 cm2 by integrating thin photoresist and vibration method. Nanopillar array can be regularly arranged, and the array dimensions of width and height are 250 nm–300 nm and 1.56 µm (aspect ratio, 6.2:1–5.2:1, respectively). The current density of 1.044 mA/cm2 is found from nanopillar electrode which is three times larger than that from the planar electrode at electrode potential of 1 V. The current density from planar electrode is 0.319 mA/cm2 under the same potential. We found the nanopillar electrode DMFC of 58.4 µW/cm2 power density showed maximum 6.3 times higher than the planar electrode DMFC of 9.3 µW/cm2 power density in fuel cell test.
Color Display of Optical Thin Film (I) [ 下載 PDF ]
Cheng-Chung Lee, Tsung-Hsun Yang, Shih-Fang Liao
Color plays as an important role in our daily life since there was human culture. As the rapid growth of display and solid state lighting industry, the requirement for the variety and fidelity of color performance is much more than ever before. Hence the importance of color measurement and evaluation method increases day by day. The quality of color produced from interference of lights is remarkable, and the optical thin film which exists around our life is the principal technology to achieve this task. It has already been demonstrated in animal, plant, and mineral. At first, color system, photometry, light source, color temperature, color rendering index and color measurement will be introduced in this article. And then, several applications of optical thin film in nature and man-made will be cited as instances to discuss and analyze by using the methodology of color science.
DNA: A Native Nano-Wire in Nature [ 下載 PDF ]
Peng-Chung JangJian, Shin-Hua Tseng, Chuan-Mei Tsai, Tsai-Mu Cheng, Hsueh-Liang Chu, Chia-Ching Chang
DNA is a one-dimensional nanowire in nature. Both conformation and size distribution of DNA are stable and uniform in solution and gas phase environments. Meanwhile, the length and conformation can be regulated by designing sequences. It is may not be utilized in nanodevices by integrating these biomaterials with semi-conductor substrate. However, the low conductivity prevents the application in devices usage. However, metal ions doped DNA possesses higher conductivity and can be integrated with semi-conductor substrate. Moreover these Ni-DNA molecules exhibit negative differential resistance (NDR) behavior. This finding provides a highly potential for constructing electrical nano-devices from biological molecules. This biomaterial is a unique and designable onedimensional bio-polymer for biosensiors and nanodevices usage. In this paper we will discuss the conductivity and electro-chemical properties by self-assembly and electro-chemical techniques. By using these properties the M-DNA (metallic DNA) can be used as a bio-detector for detecting single base mismatch of DNA. Furthermore, we can create a molecular nanodevice by utilizing M-DNA.
Multi-Edge Lens Quality Measuring System [ 下載 PDF ]
Yung-Hsiang Chen, Ho-Lin Tsay, Chia-Wei Hsu, Hui-Jean Kuo
A tilted edge algorithm was used to develop a measuring machine for imaging lens characteristics. We used an infinite conjugate setup and folding of collimating beam design. The device measured an imaging optics in several different field angles simultaneously. This measurement can be performed in a single snapshot, which is often less than one second. The dimension of this measurement setup up to be as small as a desktop instrument.
Synthesis of CuInSe2 Particles by Solvothermal Methode for Solar Cell Application [ 下載 PDF ]
Wang-Lin Liu, Yen-Chao Wang, Hsiao-Chun Chu
Solar energy related technology has become more and more important in recent years. Major applications include solar cells and solar-thermal technology. Especially, the utilization of solar energy into electrical power will be the ultimate goal for a clean energy society. The highest conversion efficiency of thin film CIGS solar cells based on physical vapor deposition technology is around 20.3%. The advances of low cost and high-efficiency thin film solar cells make this vision become possible. Current research directions focus on the development of CIGS thinfilm solar cells and the integrations of tandem-cell structure for solar energy applications. In this article, we give an introduction to CIS thin-film solar cells for their material properties, vacuum/non-vacuun production technologies, and material applications.
A Great Adventure in Human Body: The Medical Endoscope [ 下載 PDF ]
Jun-Chao Zhao, Chien-Lang Wang
Since the endoscope was developed, doctors could examine the interior organs of human body more quickly. The endoscope plays an important role in surgery or emergency because doctors can examine the interior images of human body, which could not be observed from the appearance, and to find out what illness someone has in a short time. Today, the medical endoscope market is dominated by the few multinational companies. If other companies want to enter the market, they must provide customers with cheaper, easier to use, or portable products. Furthermore, if they can improve the image recognition process of endoscope, they could build up higher entry barriers for other players in the competitive market.
