Advancement in fabrication of carbon nanotube tip for atomic force microscope using multi-axis nanomanipulator in scanning electron microscope.

We have constructed a new nanomanipulator (NM) in a field emission scanning electron microscope (FE-SEM) to fabricate carbon nanotube (CNT) tip to precisely adjust the length and attachment angle of CNT onto the mother atomic force microscope (AFM) tip. The new NM is composed of 2 modules, each of which has the degree of freedom of three-dimensional rectilinear motionx,yandzand one-dimensional rotational motionθ. The NM is mounted on the stage of a FE-SEM. With the system of 14 axes in total which includes 5 axes of FE-SEM and 9 axes of nano-actuators, it was possible to see CNT tip from both rear and side view about the mother tip. With the help of new NM, the attachment angle error could be reduced down to 0° as seen from both the side and the rear view, as well as, the length of the CNT could be adjusted with the precision using electron beam induced etching. For the proper attachment of CNT on the mother tip surface, the side of the mother tip was milled with focused ion beam. In addition, electron beam induced deposition was used to strengthen the adhesion between CNT and the mother tip. In order to check the structural integrity of fabricated CNT, transmission electron microscope image was taken which showed the fine cutting of CNT and the clean surface as well. Finally, the performance of the fabricated CNT tip was demonstrated by imaging 1-D grating and DNA samples with atomic force microscope in tapping mode.

Shape control of magnesium oxysulfate granules using an ethanolamine chelate.

Shape control of inorganic nanomaterials during hydrothermal syntheses is crucial for fine-tuning the function of these materials, which are widely utilized in semiconductors, ceramics, and optical devices. In particular, magnesium compounds possess many desirable physical properties such as high thermal stability, wide band gap and high secondary electron emission yield, which allow their application as polymeric resins, cements, reinforcements, and fillers. However, conventional synthetic methods often require extreme reaction conditions such as high temperatures, high pressures, or prolonged reaction times. Additionally, various shape control methods are typically quite complicated and time consuming under conventional parameters. In this work, magnesium oxysulfate (5Mg(OH)2 x MgSO4 x 3H2O) granules of various shapes were fabricated by introducing ethanolamine chelate during hydrothermal reaction at a relatively low temperature and pressure. The strong interaction between ethanolamine and Mg2+ produced 5Mg(OH)2 x MgSO4 x 3H2O granules in the form of flakes, flowers, or whiskers through self-assembly this formation is dependent on concentration, reaction time, and temperature. The physicochemical properties of the samples were investigated using X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, and thermogravimetric analysis.

Laser marking on microcrystalline silicon film.

We present a compact dot marker using a CW laser on a microcrystalline silicon (Si) thin film. A laser annealing shows a continuous crystallization transformation from nano to a large domain (> 200 nm) of Si nanocrystals. This microscale patterning is quite useful since we can manipulate a two-dimentional (2-D) process of Si structural forms for better and efficient thin-film transistor (TFT) devices as well as for photovoltaic application with uniform electron mobility. A Raman scattering microscope is adopted to draw a 2-D mapping of crystal Si film with the intensity of optical-phonon mode at 520 cm(-1). At a 300-nm spatial resolution, the position resolved the Raman scattering spectra measurements carried out to observe distribution of various Si species (e.g., large crystalline, polycrystalline and amorphous phase). The population of polycrystalline (poly-Si) species in the thin film can be analyzed with the frequency shift (delta omega) from the optical-phonon line since poly-Si distribution varies widely with conditions, such as an irradiated-laser power. Solid-phase crystallization with CW laser irradiation improves conductivity of poly-Si with micropatterning to develop the potential of the device application.