Faculty Profiles - KIWA Toshihiko

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Laser-terahertz emission from the chemical sensing plate

Toshihiko Kiwa, Junichi Kondo, Shohei Oka, Iwao Kawayama, Hironobu Yamada, Masayoshi Tonouchi, Keiji Tsukada

2007 JOINT 32ND INTERNATIONAL CONFERENCE ON INFRARED AND MILLIMETER WAVES AND 15TH INTERNATIONAL CONFERENCE ON TERAHERTZ ELECTRONICS, VOLS 1 AND 2 Vol. 1 pp. 285-286 280 - + 2007

Language：English Publisher：IEEE

A new type of sensing system to measure the concentration of the protons in the solutions by means of the laser-terahertz emission and detection was proposed and developed. The simple layered structures of SiO2/Si thin films on a sapphire substrate were prepared as a chemical sensing plate. The system measure the amplitude of the terahertz emission from the depletion layer of SiO2/Si interface by irradiating the femtosecond laser pulses with the center wavelength of 790 nm. The solution was contacted with the SiO2 surface and the Si thin film layer was electrically grounded. An Ag/AgCl reference electrode was used to control the potential of the solution. When the proton was adsorbed on the surface of the plate, the surface electric dipole was formed at the surface, which changes the local field of the depletion layer. Thus the peak amplitude of terahertz emission was changed depending on the number of the proton adsorbed on the surface of the plate. Actually, we demonstrated that the peak amplitude of terahertz; emission from the sensing plate increased by increasing the pH values of the test solution when the bias voltage of the solution was 0 V. (pH values indicate the concentration of the proton in the solution) and the sensitivity was about 31 mu V/pH.

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Low-frequency magnetic field detection for metal sensing

Toshihiko Kiwa, Tomoaki Kawata, Keiji Tsukada

International Journal of Applied Electromagnetics and Mechanics 25 ( 1-4 ) 447 - 451 2007

Language：English Publisher：IOS PRESS

A new type of magnetic field detection system, which can operate at a frequency below 1 kHz, is proposed and developed. The system consists of a 40-turn-coil to generate the magnetic field and a magneto resistive sensor to detect both the amplitude and the phase signal of the magnetic field induced by eddy-current and magnetization of the samples. The magnetic field detection of ferro- and non-magnetic samples using the system is demonstrated and discussed. © 2007 - IOS Press and the authors. All rights reserved.

DOI： 10.3233/jae-2007-745

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Hydrogen response mechanism of a proton pumping gate FET gas sensor

Keiji Tsukada, Tomiharu Yamaguchi, Toshihiko Kiwa, Hironobu Yamada

Proceedings of IEEE Sensors 1326 - 1329 2007

Language：English Publisher：IEEE

We developed a new type hydrogen sensor for a proton pumping gate FET with a triple layer of Pd / proton conducting polymer / Pt. Compared with conventional type FET with a single catalytic metal gate, the selectivity was improved. Furthermore, two different output signals of DC and AC modulation were obtained. According to increments of the upper gate voltage to a lower gate, the sensitivity was increased. When modulation voltage was added to the upper gate voltage, AC modulation output was obtained. The response mechanism of the new type FET was investigated using several hydrogen gases and with modulation conditions. Consequently, the hydrogen response mechanism can be explained by a hydrogen dissociation reaction occurring at the upper gate, and the hydrogen gas and generated proton can pass through the proton conducting polymer, and finally an equilibrium hydrogen reaction occurs at the lower gate. These complex mechanisms can be controlled by the gate bias and modulation voltage. © 2007 IEEE.

DOI： 10.1109/ICSENS.2007.4388655

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Laser-terahertz emission from the chemical sensing plate

Toshihiko Kiwa, Junichi Kondo, Shohei Oka, Iwao Kawayama, Hironobu Yamada, Masayoshi Tonouchi, Keiji Tsukada

IRMMW-THz2007 - Conference Digest of the Joint 32nd International Conference on Infrared and Millimetre Waves, and 15th International Conference on Terahertz Electronics 285 - 286 2007

Language：English Publisher：IEEE

A new type of sensing system to measure the concentration of the protons in the solutions by means of the laser-terahertz emission and detection was proposed and developed. The simple layered structures of SiO2/Si thin films on a sapphire substrate were prepared as a chemical sensing plate. The system measure the amplitude of the terahertz emission from the depletion layer of SiO2/Si interface by irradiating the femtosecond laser pulses with the center wavelength of 790 nm. The solution was contacted with the SiO 2 surface and the Si thin film layer was electrically grounded. An Ag/AgCl reference electrode was used to control the potential of the solution. When the proton was adsorbed on the surface of the plate, the surface electric dipole was formed at the surface, which changes the local field of the depletion layer. Thus the peak amplitude of terahertz emission was changed depending on the number of the proton adsorbed on the surface of the plate. Actually, we demonstrated that the peak amplitude of terahertz emission from the sensing plate increased by increasing the pH values of the test solution when the bias voltage of the solution was 0 V. (pH values indicate the concentration of the proton in the solution) and the sensitivity was about 31 μV/pH.

DOI： 10.1109/icimw.2007.4516500

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Laser-terahertz emission readout of chemical sensors

T. Kiwa, J. Kondo, S. Oka, I. Kawayama, H. Yamada, M. Tonouchi, K. Tsukada

TRANSDUCERS and EUROSENSORS '07 - 4th International Conference on Solid-State Sensors, Actuators and Microsystems Vol. 2, p.1915-1918, 2007 1915 - 1918 2007

Language：English Publisher：IEEE

A new type of laser-terahertz emission system for the non-contact investigation of the chemical solutions has been developed. This system monitors the terahertz emission from a sensing plate, which consists of a silicon oxide and a silicon thin film layers on the sapphire substrate. The sensing of chemical solutions with the pH value between 1.68 and 10.01 was demonstrated. The amplitude of terahertz emission from the sensing plate increased with increasing the pH value. This change in the amplitude was caused by the change of the depletion layers of the silicon thin film when protons adsorbed at the surface of the sensing plate. This result indicates that fully non-contact monitoring of chemical solutions can be possible using the laser-terahertz emission system. ©2007 IEEE.

DOI： 10.1109/SENSOR.2007.4300533

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低周波渦流探傷検査システムの金属溶接部評価への適用

長谷川照起, 石原雄大, 林孝之, 山田博信, 紀和利彦, 塚田啓二

電気学会基礎・材料・共通部門大会講演論文集(CD-ROM) 2007 2007

FET型水素センサのガス選択性改善

山口富治, 滝澤正教, 紀和利彦, 山田博信, 塚田啓二

電気学会全国大会講演論文集 2007 ( 3 ) 2007

パルス渦流探傷によるフーリエ解析手法の開発

紀和利彦, 河田知明, 山田博信, 塚田啓二

電気学会全国大会講演論文集 2007 ( 2 ) 2007

プロトンポンピングゲート構造をもったFET型水素センサ

塚田啓二, 山口富治, 紀和利彦, 山田博信

電気学会全国大会講演論文集 2007 ( 3 ) 2007

Response Properties of Proton Pumping Gate FET Hydrogen Gas Sensor

山口富治, 滝澤正教, 紀和利彦, 山口博信, 塚田啓二

電気学会ケミカルセンサ研究会資料 CHS-07 ( 23-48 ) 2007

電解質溶液中のイオン輸送現象の磁気的解析

小林史幸, 新井裕之, 紀和利彦, 塚田啓二

日本応用磁気学会学術講演概要集 31st 2007

Pt-FET型水素センサの選択性評価

中田章太, 山口富治, 紀和利彦, 山田博信, 塚田啓二

電気学会全国大会講演論文集 2007 ( 3 ) 2007

低周波磁気検査によるステンレス溶接の欠陥評価

林孝之, 林孝之, 山田博信, 紀和利彦, 玉積正司, 塚田啓二

日本応用磁気学会学術講演概要集 31st 2007

テラヘルツ波を用いた非接触化学センサープレートの開発

紀和利彦, 近藤純一, 岡昇平, 川山巌, 山田博信, 斗内政吉, 塚田啓二

応用物理学関係連合講演会講演予稿集 54th ( 3 ) 2007

テラヘルツ波pHセンサーシステムの開発

近藤純一, 岡昇平, 紀和利彦, 山田博信, 塚田啓二, 川山巌, 斗内政吉

電気学会全国大会講演論文集 2007 ( 3 ) 2007

Measurement of hydrogen gas diffusion with FET sensors

吉武剣, 坪井公輔, 山口富治, 山田博信, 紀和利彦, 塚田啓二

電気学会ケミカルセンサ研究会資料 CHS-07 ( 23-48 ) 2007

穀物水分量の新しい磁気計測方法

塚田啓二, 紀和利彦

応用物理学関係連合講演会講演予稿集 54th ( 1 ) 2007

磁場計測を用いた新しい電気化学測定システムの開発

新井裕之, 小林史幸, 紀和利彦, 塚田啓二

電気学会基礎・材料・共通部門大会講演論文集(CD-ROM) 2007 2007

低周波磁気検査システムを用いた積層構造内部の欠陥評価

山田博信, 石原雄大, 紀和利彦, 塚田啓二, 玉積正司

電気学会全国大会講演論文集 2007 ( 1 ) 2007

低周波磁場照射による水の磁気応答特性

塚田啓二, 増田祐生, 紀和利彦

応用物理学関係連合講演会講演予稿集 54th ( 1 ) 2007

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