Takao Sawada

25.2: Fabrication of CNT Electron Source by Simple Stacking for Obtaining Uniform Emission Distributions

We have developed the technique of fabricating triode structure with simple stacking method by forming an extremely smooth CNT layer and by activating CNT with a unique laser irradiation method. A test panel proves good emission property and uniformity.

Temperature dependence of magnetic field sensors using (Cd1−xMnx)Te and a light‐emitting‐diode light source

Verdet constants and optical transmissions of (Cd1−xMnx)Te solid solutions are determined as a function of Mn concentration, temperature, and wavelength. The sensitivity or modulation depth of magnetic field sensors using Faraday rotation in magneto‐optical materials is analyzed using an effective Verdet constant. The effective Verdet constant is defined by a weighted average of normal Verdet constants. The average is over the spectral profile of the light source and is weighted by the intensity of transmitted light through the material and filter. The temperature dependence of the sensitivity in the sensors using (Cd,Mn)Te in various Mn concentrations and light‐emitting‐diode light sources is discussed.

Low-temperature growth of carbon nanotube by thermal chemical vapor deposition with FeZrN catalyst

Recently the direct growth of carbon nanotubes (CNT) on glass substrates by thermal chemical-vapor deposition at low temperatures has been researched for the fabrication of field-emission displays. We have achieved synthesis of CNT on soda lime glass with a catalyst: FeZrN at low temperature (500–550 °C). The FeZrN film deposited by sputtering is amorphous. However, this film changes into a crystalloid to separate out Fe fine particles by thermal treatment. This characteristic has been successfully applied to make the precursor of CNT. There is a possibility that the density and diameter of CNT can be controlled by varying the composition ratio of FeZrN. The emission from CNT has also been obtained. The turn-on electric field has been ∼2.5–3 V/μm. We have fabricated a microtriode structure and the emission has been also recognized.

Substantial Reduction of Power Loss in a 14kVA Inverter Using Paralleled SiC-MOSFETs and SiC-SBDs

For higher power application of SiC devices, we have designed and developed an inverter module with paralleled SiC-MOSFETs and SiC-SBDs.We have successfully completed the operation of the SiC inverter module at continuous rating of up to 11kW with carrier frequency of 20 kHz. The power loss during the operation was measured by calorimetric method and the results showed that the loss was considerably reduced by 30% of a similar rating commercialized IGBT power module at carrier frequency of 15 kHz.

53.1: Fabrication of CNT Emitter Array with Polymer Insulator

A new method of fabricating CNT emitter array using polymer insulator with low outgassing has been developed. A dry etching process without the damage on the CNT has been found and it proved to decrease the turn-on voltage. Better emission properties than conventional insulator has been obtained.

Growth technique and optical characterization of (Cd,Mn)Te for fiber-optic magnetic field sensors

Crystal growth of Cd1−xMnxTe (x > 0.4) with giant Faraday rotation has been studied for applications as fiber-optic magnetic field sensors. These crystals contain two types of inclusions: large-sized (>10 μm) manganese oxide and small-sized (<2 μm) manganese telluride. Both inclusions decreased with purification of the Mn metal surface and optimisation of growth conditions. As a result, single crystals with low extinction ratio ( <10−4) and transmission loss ( < 0.45 dB/mm) at 660 nm were obtained.

Measurement of Stress Induced Birefringence of Bi12GeO20 Single Crystals by a New Ellipsometry

Optical qualities of Bi12GeO20 single crystals with facets are determined. A facet has higher absorbance and larger refractive index by 3×10-4 than those of off facet. Stress induced birefringence and extinction ratio are examined by a new ellipsometry for evaluating an optical active birefringent medium. Birefringence exists around {110} facet, the maximum retardation reaches 4 degrees per 1 mm thickness. Light is scatterd at the {110} facet boundary, and extinction ratio reaches -35 dB at the maximum point. On the contrary, the extinction ratio inside the facet and off-facet region is under -45 dB.

Growth of Carbon Nanotube by Thermal Chemical Vapor Deposition at Low Temperature with FeZrN Film

Recently, the direct growth of carbon nanotubes on a glass substrate by thermal chemical vapor deposition (CVD) at low temperatures has been studied for the fabrication of field emission displays (FEDs). We achieved the synthesis of carbon nanotubes on soda lime glass at low temperatures (500–550°C) by a novel granulation method using FeZrN film. The FeZrN film is amorphia direct after sputtering, however, it changes into crystalloid to separate out Fe fine particles by thermal treatment. The characteristic was applied to successfully make the precursor of carbon nanotubes. The emission was also obtained and the turn-on electron field was approximately 3 V/µm.