B- and P-Doped Si0.8Ge0.2 Thin Film Deposited by Helicon Sputtering for the Micro-Thermoelectric Gas Sensor

2006 ◽  
Vol 320 ◽  
pp. 99-102 ◽  
Author(s):  
Kazuki Tajima ◽  
Woosuck Shin ◽  
Maiko Nishibori ◽  
Norimitsu Murayama ◽  
Toshio Itoh ◽  
...  
Keyword(s):  
Thin Film ◽  
Hydrogen Oxidation ◽  
Exothermic Reaction ◽  
High Sensitivity ◽  
Hydrogen Sensor ◽  
Thermoelectric Effect ◽  
Boron Doped ◽  
Reliable Monitoring ◽  
Ppm Level ◽  
Pt Catalyzed

Micro-thermoelectric hydrogen sensor (micro-THS) with the combination of the thermoelectric effect of Si0.8Ge0.2 thin film and the Pt-catalyzed exothermic reaction of hydrogen oxidation was prepared by microfabrication process. In the viewpoint of high sensitivity of micro-THS, the thermoelectric properties of the Si0.8Ge0.2 thin film could be improved by optimizing carrier concentration using helicon sputtering with an advantage of easy doping control, and sensitivity of the device with this thin film was investigated. As the result, the boron-doped Si0.8Ge0.2 thin film is considered to be the better choice ensuring the reliable monitoring of hydrogen concentration down to ppm level.

Microfabrication of Thermoelectric Hydrogen Sensor Using KOH Solution Etching

2006 ◽  
Vol 301 ◽  
pp. 273-276 ◽  
Author(s):  
Kazuki Tajima ◽  
Yeong Soo Choi ◽  
Woosuck Shin ◽  
Noriya Izu ◽  
Ichiro Matsubara ◽  
...  
Keyword(s):  
Integrated Circuit ◽  
Hydrogen Oxidation ◽  
Exothermic Reaction ◽  
High Sensitivity ◽  
Response Speed ◽  
Hydrogen Sensor ◽  
Fast Response ◽  
Sensor Technology ◽  
Circuit Fabrication ◽  
Voltage Signal

Micromachined sensors are a new generation of sensor technology combining existing integrated circuit fabrication technology with novel deposition and etching processing. In the viewpoint of low-power operation, high sensitivity and fast response speed of thermoelectric hydrogen sensor (THS), we prepared the micromachined thermoelectric hydrogen sensor (micro-THS) with the combination of the thermoelectric effect of SiGe thin film and the Pt-catalyzed exothermic reaction of hydrogen oxidation. The power consumption of the micro-THS was greatly reduced to be 50 mW for 100 °C operating, by the Pt-micro-heater on single membrane. The micro-THS with 40 wt.% Pt/alumina catalyst showed voltage signal of 10 mV for 1 % H2 in air.

Micro Hydrogen Gas Sensor Based on Bi-Te Film Couples and Pt/ACC

2007 ◽  
Author(s):  
Hu Huang ◽  
Jian-Song Zhang ◽  
Weiling Luan ◽  
Shan-Tung Tu ◽  
Shang-Kuo Yang
Keyword(s):  
Gas Sensor ◽  
Hydrogen Oxidation ◽  
Exothermic Reaction ◽  
High Sensitivity ◽  
Clean Energy ◽  
Rf Magnetron Sputtering ◽  
Energy System ◽  
Hydrogen Gas ◽  
Activated Carbon Fiber ◽  
Thin Glass

TE (Thermoelectric) materials have been widely used in clean energy system as low-power generator and Peliter cooler, due to its salient features of being compact, light-weighted, noiseless in operation, highly reliable, and environment friendly. Recently, another application has been explored on TE materials as gas sensors based on Seebeck effect and exothermic reaction of hydrogen oxidation on catalyst. In this paper, a TE hydrogen gas sensor with a simple structure, low energy consumption and a high sensitivity was reported. Bi-Te (bismuth telluride) with a high Seebeck coefficient at room-temperature was deposited onto thin glass substrates by RF magnetron sputtering technology. Four pairs of PN film couples were connected in series to improve the output voltage. Pt/ ACC (Activated Carbon Fiber Cloth) was mounted at the joint of PN couples, acting as catalyst so as to accelerate the oxidation of hydrogen. The influences of reduction temperature and Pt content on the generated temperature difference were investigated. The voltage output and selectivity to combustible gas mixture were measured. Experimental results showed that when exposed to 3vol% H2/ air, as-prepared sensor gave out a high output signal of 33.1mV, and the response time was about 50s with recovery time of 50s.

scholarly journals Development of a High Stability Pd-Ni Alloy Thin-Film Coated SAW Device for Sensing Hydrogen

Sensors ◽  
2019 ◽  
Vol 19 (16) ◽  
pp. 3560 ◽  
Author(s):  
Wen Wang ◽  
Xueli Liu ◽  
Shengchao Mei ◽  
Mengwei Liu ◽  
Chao Lu ◽  
...  
Keyword(s):  
Thin Film ◽  
High Sensitivity ◽  
Hydrogen Sensor ◽  
Fast Response ◽  
Propagation Path ◽  
Alloy Thin Film ◽  
Optimal Parameters ◽  
Ni Alloy ◽  
Oscillation Loop ◽  
Coated Surface

A Pd-Ni alloy thin-film coated surface acoustic wave (SAW) device is proposed for sensing hydrogen. The Pd-Ni thin-film was sputtered onto the SAW propagation path of a SAW device with a delay line pattern to build the chip-sized hydrogen sensor. The prepared sensor chip was characterized by employing a differential oscillation loop. The effect of the Pd-Ni film thickness on sensing performance was also evaluated, and optimal parameters were determined, allowing for fast response and high sensitivity. Excellent working stability (detection error of 3.7% in half a year), high sensitivity (21.3 kHz/%), and fast response (less than 10 s) were achieved from the 40 nm Pd-Ni alloy thin-film coated sensing device.

Boron-Doped Si[sub 0.8]Ge[sub 0.2] Thin Film Deposited by Helicon Sputtering for Microthermoelectric Hydrogen Sensor

2007 ◽  
Vol 154 (1) ◽  
pp. J53 ◽  
Author(s):  
Kazuki Tajima ◽  
Woosuck Shin ◽  
Lionel Fabrice Houlet ◽  
Toshio Itoh ◽  
Noriya Izu ◽  
...  
Keyword(s):  
Thin Film ◽  
Hydrogen Sensor ◽  
Boron Doped

Steady-State Modeling of Pt-Catalyzed H2 Combustion in a Monolithic Reactor: From Micro- to Macro-kinetics

2016 ◽  
Vol 14 (1) ◽  
pp. 373-381 ◽  
Author(s):  
Qi Su ◽  
Xiao-Ling Zha ◽  
Jin Xu ◽  
Wei-Fang Yu
Keyword(s):  
Steady State ◽  
Kinetic Modeling ◽  
Hydrogen Oxidation ◽  
Exothermic Reaction ◽  
Reaction System ◽  
Surface Species ◽  
Parametric Sensitivity ◽  
Composition Effects ◽  
Steady State Model ◽  
Pt Catalyzed

AbstractMicro-kinetic modeling of Pt-catalyzed hydrogen oxidation in a monolithic reactor was carried out for various feed temperatures. The monolith behavior was described by a simplified steady-state model that avoids surface species enthalpy evaluation and does not have temperatures as unknowns. A simplified pseudoarch length method was used to obtain the multiple solution branches for this typical exothermic reaction system. Based on parametric sensitivity and surface species distribution analyses of the micro-kinetic modeling results, macro-kinetic models that involve only gas concentrations were derived and were used to explain the composition effects on ignition temperature.

High Sensitivity pH Sensors based on Amorphous Indium-gallium-zinc Oxide Thin-film Transistors

2015 ◽  
Vol 135 (6) ◽  
pp. 192-198 ◽  
Author(s):  
Shinnosuke Iwamatsu ◽  
Yutaka Abe ◽  
Toru Yahagi ◽  
Seiya Kobayashi ◽  
Kazushige Takechi ◽  
...  
Keyword(s):  
Thin Film ◽  
Zinc Oxide ◽  
Thin Film Transistors ◽  
High Sensitivity ◽  
Oxide Thin Film ◽  
Indium Gallium Zinc Oxide ◽  
Ph Sensors ◽  
Zinc Oxide Thin Film ◽  
Indium Gallium

Reduction of Wind Disturbance by Optimizing the Drive Current of Pt Ultra-thin Film Hydrogen Sensor

2020 ◽  
Vol 140 (4) ◽  
pp. 92-96
Author(s):  
Yuto Goda ◽  
Hiroto Shobu ◽  
Kenji Sakai ◽  
Toshihiko Kiwa ◽  
Kenji Kondo ◽  
...  
Keyword(s):  
Thin Film ◽  
Hydrogen Sensor ◽  
Wind Disturbance ◽  
Drive Current ◽  
Ultra Thin Film

Investigation of Nanometric Thin-Film Bismuth Piezoresistors Deposited on Silicon Substrates

2012 ◽  
Vol 1477 ◽  
Author(s):  
Horacio V. Estrada
Keyword(s):  
Thin Film ◽  
Axial Strain ◽  
High Sensitivity ◽  
Metal Alloys ◽  
Silicon Substrates ◽  
Transverse Strain ◽  
Bending Stress ◽  
Pure Bending ◽  
Strain Fields ◽  
Strain Axis

ABSTRACTThin film bismuth piezoresistors, defined on oxidized silicon wafers, are investigated as a function of their orientation for their eventual integration on micro-electro-mechanical (MEMS) microsensors. Bismuth’s piezoresistance (or elasto-resistance) is experimentally investigated to accurately determine its longitudinal and transverse strain sensitivities. Whisker-shaped resistive elements defined on different orientations (from 0o, the beam’s main strain axis, to 90o, perpendicular to that axis) undergo changes of resistance (ΔR), associated with the induced strains on silicon cantilevers beam’s surface when these are mechanically loaded under pure bending stress conditions. For Bi-resistors, the traditional gage factor concept, (ΔR/Ro)/εl, is found to be equal to +16 and +33, for elements oriented along 0 and 90o, respectively, considerably larger than those for metals or metal alloys. These high sensitivity values and the “unusual” positive, higher value for the 90o (perpendicular) resistors can be of considerable interest for microsensors applications. The results of this study enable us to precisely determine the bismuth’s longitudinal and transverse strain sensitivities that are calculated to be equal to +26 and +40.5 respectively. This experimental study is extended to explore the Bi-films’ response to bi-axial strain fields.

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