• 센서학회지
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• 제1권2호
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• pp.117-123
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• 1992

적층구조의 Pt-Sn 박막을 히터 위에서 열산화하여 $Pt-SnO_{2-x}$ 박막형 CO 가스감지소자를 제조하였다. 열증착법으로 증착된 Sn의 두께는 $4000{\AA}$이었으며 그 위에 D.C. sputtering법으로 증착된 Pt의 두께는 $14{\AA}{\sim}71{\AA}$ 이었다. XRD 분석에서 $Pt-SnO_{2-x}$ 박막은 $200{\AA}$ 정도의 입경과 주방향성이 (110)인 $(SnO_{2}){\cdot}6T$ 결정상을 보였다. $Pt-SnO_{2-x}$ 박막소자(Pt 두께 : $43{\AA}$)는 6000 ppm의 CO에 대해 80% 정도의 감도와 CO에 대해 높은 선택도를 나타내었다. 그리고 CO에 고감도를 갖는 $Pt-SnO_{2-x}$ 박막소자의 열산화 온도와 동작온도가 각각 $500^{\circ}C$와 $200^{\circ}C$이었다.

• 센서학회지
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• 제19권1호
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• pp.58-61
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• 2010

This paper describes the fabrication and characteristics of NO sensor using ZnO thin film by RF magnetron sputter system. The sensitivity, working temperature, and response time of sputtered pure ZnO thin film and added catalysts such as Pt, Pd, Al, Ti on those films were measured and analyzed. The sensitivity of pure ZnO thin film at working temperature of $300^{\circ}C$ is 0.875 in NO gas concentration of 0.046 ppm. At same volume of the gas in chamber, measuring sensitivity of 1.87 at $250^{\circ}C$ was the case of Pt/ZnO thin film. The ZnO thin films added with catalyst materials were showed higher sensitivity, lower working temperature and faster adsorption characteristics to NO gas than pure ZnO thin film.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2010년도 춘계학술대회 논문집
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• pp.549-550
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• 2010

• 대한전자공학회논문지
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• 제26권11호
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• pp.1631-1636
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• 1989

A space charge model for semiconductor reduced gas sensors has been roposed and applied to gas sensing mechanism. SnO2-x and SnO2-x/Pt thin film were deposited by vacuum evaporating method. And Hall effect and gas sensitivity characteristics of these sensors were measured. From the space charge model and carrier concentration, the number of the adsorbed gas atom on the solid surface was calculated quantitatively. The gas sensing model was compared with CO gas sensitivities of the fabricated thin film gas sensors.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 D
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• pp.1756-1758
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• 1999

As new gas sensing material with high cata activity for NO decomposition and for CO oxid $LaFeO_3$ thin films with different thicknesses fabricated by the R.F. magnetron sputtering m on an $Al_2O_3$ substrates with Ag electrodes. The sensing characteristics of the $LaFeO_3$ thin films studied as a function of annealing temperature film thickness. The thin film annealed at showed the highest sensitivity of 110% for CO 60% for NO.

• Journal of Korean Society for Atmospheric Environment
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• 제20권E2호
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• pp.69-75
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• 2004

In this study, thin film gas sensor based on tin oxide was fabricated to examine its characteristics. Target gas is acetonitrile ($CH_3$CN) which is a blood simulant for the chemical warfare agent. Sensing materials are SnO$_2$ SnO$_2$/Pt, and Sn/Pt with thickness from 1000 to 3000 $\AA$. The sensor consists of a sensing electrode with inter-digit (IDT) type in front side and a heater in rear side. Resistance changes of sensing materials are monitored on real time basis using a data acquisition board with a 12-bit analog to digital converter. Sensitivities are measured at different operating temperatures also with different gas concentrations and film thickness. The high sensitivity is obtained for Sn (3000 $\AA$)/Pt (30 $\AA$) at 30$0^{\circ}C$ for 3 ppm. Response and recovery times were about 40 and 160 s, respectively. Repetition measurements showed very good results with $\pm$3% in full scale range.

• 한국세라믹학회지
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• 제30권9호
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• pp.701-708
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• 1993

Pd-doped SnO2 thin films for hydrogen gas sensing were fabricated by reactive fo magnetron sputtering and were studied on effects of film thickness and Pd doping content. Pd doping caused the optimum sensor operation temperature to reduce down to ~25$0^{\circ}C$ and also enhanced gas sensitivity, compared with undoped SnO2 film. Gas sensitivity depended on the film thickness. The sensitivity increased with decreasing the film thickness, showing maximum sensitivities at the thickness of 730$\AA$ and 300~400$\AA$ for the undoped SnO2 and the Pd-doped SnO2 film, respectively. Further decrease of the film thickness beyond these thickness ranges, however, resulted in the reduction of sensitivity again.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제49권2호
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• pp.82-86
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• 2000

Humidity sensors using $TiO_2$ thin films were fabricated on the multi-electrode device by Sol-Gel method and their wettability, surface potential decays and humidity sensing characteristics were investigated. Contact angle of thin films was $28^{\cic}\;at\; 400^{\circ}C$ and surface potential decayed rapidly at $400^{\circ}C$. The specimen showed best humidity sensing characteristics at $400^{\circ}C$. From the results, they were confirmed that humidity sensing characteristics of thin films have connection with contact angle and surface potential decays.

• 한국재료학회지
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• 제23권9호
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• pp.477-482
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• 2013

We investigated the detection properties of nitrogen monoxide (NO) gas using transparent p-type $CuAlO_2$ thin film gas sensors. The $CuAlO_2$ film was fabricated on an indium tin oxide (ITO)/glass substrate by pulsed laser deposition (PLD), and then the transparent p-type $CuAlO_2$ active layer was formed by annealing. Structural and optical characterizations revealed that the transparent p-type $CuAlO_2$ layer with a thickness of around 200 nm had a non-crystalline structure, showing a quite flat surface and a high transparency above 65 % in the range of visible light. From the NO gas sensing measurements, it was found that the transparent p-type $CuAlO_2$ thin film gas sensors exhibited the maximum sensitivity to NO gas in dry air at an operating temperature of $180^{\circ}C$. We also found that these $CuAlO_2$ thin film gas sensors showed reversible and reliable electrical resistance-response to NO gas in the operating temperature range. These results indicate that the transparent p-type semiconductor $CuAlO_2$ thin films are very promising for application as sensing materials for gas sensors, in particular, various types of transparent p-n junction gas sensors. Also, these transparent p-type semiconductor $CuAlO_2$ thin films could be combined with an n-type oxide semiconductor to fabricate p-n heterojunction oxide semiconductor gas sensors.

• Journal of Industrial and Engineering Chemistry
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• 제67권
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• pp.417-428
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• 2018

In this study, we fabricated hierarchically self-assembled thin films composed of graphene oxide (GO) sheets and gold nanoparticles (Au NPs) using the Langmuir-Blodgett (LB) and Langmuir-Schaefer (LS) techniques and investigated their gas-sensing performance. First, a thermally oxidized silicon wafer ($Si/SiO_2$) was hydrophobized by depositing the LB films of cadmium arachidate. Thin films of ligand-capped Au NPs and GO sheets of the appropriate size were then sequentially transferred onto the hydrophobic silicon wafer using the LB and the LS techniques, respectively. Several different films were prepared by varying the ligand type, film composition, and surface pressure of the spread monolayer at the air/water interface. Their structures were observed by scanning electron microscopy (SEM) and atomic force microscopy (AFM), and their gas-sensing performance for $NH_3$ and $CO_2$ was assessed. The thin films of dodecanethiol-capped Au NPs and medium-sized GO sheets had a better hierarchical structure with higher uniformity and exhibited better gas-sensing performance.