Reo Kometani

Evaluation of Field Electron Emitter Fabricated Using Focused-Ion-Beam Chemical Vapor Deposition

We carried out the field-emission characterization of materials, such as diamond-like carbon (DLC), W, and Fe, deposited by focused-ion-beam chemical vapor deposition (FIB-CVD) to develop a field emitter to be used as a nano-tool for spot deposition. As a result, the threshold voltage of the field emission from the DLC was lower than those from the W and Fe. In addition, we measured the work functions of these materials using photoelectron spectroscopy and found that DLC has a low work function. Furthermore, a field emitter with a DLC tip as a cold cathode was fabricated on a glass capillary, because it was found to be able to emit electrons from the DLC using a low voltage. We also confirmed that electrons were emitted from a DLC tip fabricated by FIB-CVD.

Elementary Analysis of Diamond-Like Carbon Film Formed by Focused-Ion-Beam Chemical Vapor Deposition

This is the first report on the precise elemental composition of a diamond-like carbon (DLC) thin film fabricated by focused-ion-beam chemical vapor deposition (FIB-CVD). The atomic fraction of the FIB-CVD DLC film has been determined to be C:Ga:H=87.4:3.6:9.0 at. % using Rutherford backscattering spectrometry (RBS) and elastic recoil detection analysis (ERDA). The hydrogen content of the FIB-CVD DLC film was lower than that of DLC films formed using other CVD methods.

Evaluation of a Bio Nano-Sensing Probe Fabricated by Focused-Ion-Beam Chemical Vapor Deposition for Single Organelle Analyses

It is necessary to manipulate and analyze single cells and organelles with high accuracy for a deeper understanding of their biological phenomena. For this purpose, bio nano-tools are very useful. We fabricated a bio nano-sensing probe by using focused-ion-beam chemical vapor deposition (FIB-CVD) and evaluated it using a cell of an Egeria densa leaf. We found that the probe functions as a measurement electrode. This indicates that the bio nano-sensing probe is useful for single organelle analyses.

Relationship between Field Emission Properties and Material Characteristics of Diamond-Like Carbon Fabricated by Focused-Ion-Beam Chemical Vapor Deposition

Diamond-like carbon (DLC) deposited by focused-ion-beam chemical vapor deposition (FIB-CVD) contains gallium (Ga) when a Ga ion beam is used. Therefore, DLC deposited by FIB-CVD (FIB-DLC) has specific material characteristics that differ from those of typical DLC. In this study, FIB-DLCs annealing-temperature dependence of field emission properties, work functions, and surface conditions were measured to understand its material characteristics. The results show that Ga incorporation is required in order to obtain a sufficient electric conductivity for the field emission. Furthermore, we found that the work function is increased by the graphitization of the FIB-DLC surface caused by the annealing treatment.

Dynamic nano- and micro-devices based on protein motors

Protein motors are enzymes that naturally generate force and move along tracks of protein polymers (actin filaments or microtubules), using energy from the hydrolysis of adenosinetriphosphate (ATP). To harness these protein motors to power nanometer-scale devices, we have investigated effective and non-destructive methods for immobilizing protein motors on surfaces and to arrange the output of these motors, e.g. force and movement, to be in a defined direction. We found polymethylmethacrylate (PMMA) and NEB-22 to be useful for immobilizing protein motors while retaining their abilities to support the movement of protein polymers. We fabricated various patterns of tracks of PMMA or NEB22 on coverslips and protein motors were introduced and immobilized on the patterns. The trajectories of protein polymers were confined to these tracks. Simple patterns readily biased polymer movement confining it to be unidirectional. Applications of motor proteins in nanometric fine-movement microactuators are now stepping closer to reality.

Evaluation of Vacuum Microcapsule Fabricated using Focused-Ion-Beam Chemical-Vapor-Deposition

We fabricated a silicon dioxide-based vacuum microcapsule using focused-ion-beam chemical-vapor-deposition (FIB-CVD) to realize three high-performance vacuum electronic micro-devices: a diode, a triode, and a sensor. We measured the electrical characteristics of diamond-like carbon (DLC) and silicon dioxide (SiO2) deposited using FIB-CVD, and found that they had characteristics that are useful in conductors and insulators, respectively, used in vacuum micro-device fabrication. Furthermore, to evaluate the inner vacuum of a microcapsule, a diode with a microcapsule was fabricated using FIB-CVD. By measuring the current–voltage (I–V) characteristics of the diode, it was demonstrated that the inner vacuum of the microcapsule was maintained. This result indicates that various high-performance three-dimensional vacuum micro-devices can be fabricated using FIB-CVD on any surface.