Papers by Masahiko Kumadaki
Scientific reports, Apr 15, 2024
Bio-semiconductors are expected to be similar to organic semiconductors; however, they have not b... more Bio-semiconductors are expected to be similar to organic semiconductors; however, they have not been utilized in application yet. In this study, we show the origin of electron appearance, N-and S-type negative resistances, rectification, and switching effects of semiconductors with energy storage capacities of up to 418.5 mJ/m 2 using granulated amorphous kenaf cellulose particles (AKCPs). The radical electrons in AKCP at 295 K appear in cellulose via the glycosidic bond C 1 -O 1 • -C 4 . Hall effect measurements indicate an n-type semiconductor with a carrier concentration of 9.89 × 10 15 /cm 3 , which corresponds to a mobility of 10.66 cm 2 /Vs and an electric resistivity of 9.80 × 10 2 Ωcm at 298 K. The conduction mechanism in the kenaf tissue was modelled from AC impedance curves. The light and flexible cellulose-semiconductors may open up new avenues in soft electronics such as switching effect devices and bio-sensors, primarily because they are composed of renewable natural compounds.
IEEJ Transactions on Electronics, Information and Systems, 2015
Plasma measuring methods have been developed to measure the properties of plasmas which cannot be... more Plasma measuring methods have been developed to measure the properties of plasmas which cannot be touched directly. For instance, Quadropole Mass Spectroscopy (QMS) was developed to survey what kinds of compound are included in the plasma directly. We have measured by using Plasma Emission Spectroscopy method. It has been considered to be one of the effective method because of not affecting the plasma. We have developed a new type of plasma spectroscopic device by an image processing method. On this paper, we’d like to report advantages and differences between the new device and the old one.
IEEJ Transactions on Fundamentals and Materials, 2014
We deposited SiCN thin films by RF plasma CVD (Chemical Vapor Deposition) method using a mixture ... more We deposited SiCN thin films by RF plasma CVD (Chemical Vapor Deposition) method using a mixture of Tetramethylsilane (TMS), nitrogen, and hydrogen gas. Deposited films were measured some properties with Fourier-Transform Infrared Spectroscopy (FT-IR), X-ray Photoelectron Spectroscopy (XPS), Ellipsometry and Atomic Force Microscope (AFM). We found that the temperature of substrate increased elimination and absorption reaction on the surface, and a fine film could be deposited at the temperature of 973K. To deposit SiCN with lower temperature, we changed H2 flow rate. As results, we found that H2 flow rate had great influence on the efficiency of decomposition of TMS. Moreover, the roughness of substrate was affected by the mixture rate of TMS. We could obtain the films nearly similar to the 973K ones at the state of 100Pa of pressure, 773K of substrate temperature, 80sccm of H2 flow rate, and TMS mixture rate of 3% to 5%. In particular, 5% of TMS mixture rate could be considered as the best condition on this experiment.
IEEJ Transactions on Fundamentals and Materials, 2014
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Papers by Masahiko Kumadaki