• Title/Summary/Keyword: Humidity-sensing material

Search Result 38, Processing Time 0.024 seconds

Humidity Sensor Using an Air Capacitor

  • Choi, Jin Moon;Kim, Tae Wan
    • Transactions on Electrical and Electronic Materials
    • /
    • v.14 no.4
    • /
    • pp.182-186
    • /
    • 2013
  • We studied the possibility that an air capacitor can be used as a humidity sensor by measuring capacitance change. In order to investigate the possibility, the change of capacitance of an air capacitor due to moisture in air was first considered theoretically, and was then experimentally verified. The capacitance was measured by an LCR impedance meter with a 100-kHz and 1-V ac. The results revealed that the changes in the experimentally measured capacitances were greater than those in the theoretically calculated values. Based on this fact, we knew that an air capacitor could be used as part of a humidity sensing device. We expect the humidity sensor with an air capacitor has characteristics of fast response time, high reliability, and high durability compared with other conventional methods.

A Resistive-Type Humidity Sensor Using PMMA Thin Film (PMMA를 이용한 저항형 습도감지소자)

  • Lee, Sung-Pil;Rim, Jae-Young;Yoon, Yeo-Kyoung
    • Journal of Sensor Science and Technology
    • /
    • v.1 no.2
    • /
    • pp.125-130
    • /
    • 1992
  • A resistive-type humidity sensors have been fabricated using cross-linked PMMA thin film as sensing material and their humidity characteristics have been investigated. The sensor coated of the cross-linked PMMA with PVA exhibited largely variation of resistance by increase of relative humidity and less than 3% of hysteresis. Furthermore, the fabricated sensor exhibited superior long-term stability. The response time of the PMMA humidity sensor was about 7 min. for adsorption and about 5 min. for desorption respectively.

  • PDF

Effect of $Li_2O$ and $Na_2O$ addition on the microstructure and humidity sensitivity of $V_ 2O_5$-doped $TiO_2$ ($V_2O_5$를 도판트한 $TiO_2$의 미세구조와 감습에 미치는 알카리 옥사이드$ M_2O(M=Li,Na)$의 영향)

  • 신용덕
    • Electrical & Electronic Materials
    • /
    • v.9 no.6
    • /
    • pp.605-615
    • /
    • 1996
  • In this paper, the effect of alkaline oxide addition such as Li$_{2}$O and Na$_{2}$O on the microstructure and humidity sensitivity of V$_{2}$O$_{5}$(2 mol%)-doped TiO$_{2}$(98 mol%) was investigated as a function of amount (0, 1, 2, 5, 10 mol%) of Li$_{2}$O and Na$_{2}$O additives. The pores in the alkaline free sample were distributed mostly in the range between 0.16 and 1.0.mu.m in diameter and its porosity was 23.29%. Li$_{2}$O caused grain overgrowth and reduced the porosity with a narrow distribution of the pore size, leading to poor humidity sensitivity. Na$_{2}$O helped to enlarge the distribution of the pore size through the formation of small soluble phases. The pore sizes of the sample containing Na$_{2}$O 2mol% were distributed mostly in the range between 1.0 and 2.5.mu.m in diameter and its porosity and intrusion volume of mercury were 31.13 % and 0.1155 mL/g respectively, which consequently improved the humidity sensing characteristics such as the sensitivity and temperature-stability. Especially, the addition of 2mol% of Na$_{2}$O improved the humidity-sensing characteristics such as sensitivity and linearity in the whole range between 30 and 90 %RH (Percentage Relative Humidity)y)

  • PDF

Resistive Polymeric Humidity Sensor Fabricated with Ink-Jet Printing Technique (잉크젯 프린팅을 이용한 저항형 고분자 습도센서)

  • 공명선;금내리
    • Journal of the Microelectronics and Packaging Society
    • /
    • v.11 no.1
    • /
    • pp.49-57
    • /
    • 2004
  • The modified polyionene polyelectrolyte inks were newly prepared and applied to the humidity-sensitive membrane of humidity sensor. The films were fabricated on the alumina substrate with comb-type gold electrode using a ink-jet printing technique. The copolymers of methyl methacrylate, acrylic acid, 2-hydroxyethyl methacrylate and [(2-methacryloyloxy)ethyl]trimethylammonium chloride were also prepared for the humidity-sensing material. which was fabricated by dip-coating method. Electrical measurements under various relative humidity were performed. The humidity-sensitive characteristics of sensors obtained by ink-jet printing technique were compared with that of dip-coating method. Humidity sensors showed a decrease in resistance as an increase of relative humidity and their resistance characteristics are in a close agreement each other.

  • PDF

Fabrication of Ceramic Gas Sensors at Room Temperature and Characteristics (실온동작 세라믹 가스센서의 제작 및 특성)

  • Jung, Jae-Eop;Yoon, Yeu-Kyung;Lee, Sung-Pil
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
    • /
    • 2003.07b
    • /
    • pp.814-817
    • /
    • 2003
  • As additive Pt of a little to $SnO_2$ that gas sensing property is superior oxide-semiconductor material to fabricate gas sensor that operation is possible at room temperature and fabricated ceramic gas sensing devices. And, the change amount and sintering temperature of addition material investigated gas sensitivity by change of operation temperature, humidity relativity, Long-term stability and hysteresis. And achieved SEM and XRD analysis for characteristics searching examination of devices.

  • PDF

Electrical characteristics of carbon nitride capacitor for micro-humidity sensors (마이크로 습도센서를 위한 질화탄소막 캐패시터의 전기적 특성)

  • Kim, Sung-Yeop;Lee, Ji-Gong;Chang, Choong-Won;Lee, Sung-Pil
    • Journal of Sensor Science and Technology
    • /
    • v.16 no.2
    • /
    • pp.97-103
    • /
    • 2007
  • Crystallized carbon nitride film that has many stable physical and/or chemical properties has been expected potentially by a new electrical material. However, one of the most significant problems degrading the quality of carbon nitride films is an existence of N-H and C-H bonds from the deposition environment. The possibility of these reactions with hydroxyl group in carbon nitride films, caused by a hydrogen attack, was suggested and proved in our previous reports that this undesired effect could be applied for fabricating micro-humidity sensors. In this study, MIS capacitor and MIM capacitor with $5{\mu}m{\times}5{\mu}m$ meshes were fabricated. As an insulator, carbon nitride film was deposited on a $Si_{3}N_{4}/SiO_{2}/Si$ substrate using reactive magnetron sputtering system, and its dielectric constant, C-V characteristics and humidity sensing properties were investigated. The fabricated humidity sensors showed a linearity in the humidity range of 0 %RH to 80 %RH. These results reveal that MIS and MIM $CN_{X}$ capacitive humidity sensors can be used for Si based micro-humidity sensors.

surface acoustic wave oscillator hymidity sensor using hexafluoropropene plasma thin film (헥사플루오르프로펜 플라즈마박막을 이용한 표면탄성파발진기 습도센서)

  • 박남천;서은덕
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
    • /
    • 1992.05a
    • /
    • pp.144-146
    • /
    • 1992
  • Surface acoustic wave(SAW) oscillator offers many attractive features for application to vapor sensors. The perturbation of SAW velocity by the hexafluoropropence plasma polymer thin film has been studied for relative humidity sensing. adsorption of moisture produces rapid aid changes in the properties of the film, resulting in a change in the velocity of surface acoustic waves and, hence, in the frequency of one SAW oscillator. The device used in our experiments have 55 MHZ SAW oscillator fabricated on a LiNbO substrate.

  • PDF

Characteristics of Polyimides Humility Sensor Fabricated by using Electrophoretic Deposition (전기영동법에 의해 제작된 폴리이미드 박막의 습도 특성)

  • 조동헌;정병기;한상옥;김종석;박강식
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
    • /
    • 1994.05a
    • /
    • pp.67-70
    • /
    • 1994
  • On this study, we fabricated humudity sensor with polyimide thin film from the nonaqueous emulsion by the electrophoretic deposition as a function of film thickness. then evaluated performance of the sensor with increasing relative humidity if constant temperature constant humidity chamber, which is electronically controlled. we designed upper electrode of the sensor to brush type to make moisture particles permeate into the polymer bulk. sensing properties of the sensor on % RH shows proportion on the low %RH. Fer the 30V-30S- 200$^{\circ}C$ sample, percentage changing of capacitance on from 30 %RH to 90 %RH is 45.8 %, and increasing rate per 1 % RH of capacitance is 11.25 pF

  • PDF

Study on the development of mesa-type humidity sensors using porous silicon layer (다공질 실리콘층을 이용한 메사형 습도센서의 개발에 관한 연구)

  • Kim, Seong-Jeen
    • Journal of Sensor Science and Technology
    • /
    • v.8 no.1
    • /
    • pp.32-37
    • /
    • 1999
  • A capacitance-type humidity sensor with mesa structure in which porous silicon layer is used as humidity-sensing material is developed and its humidity sensing properties are measured. This sensor has a structure where two electrodes are set on the up-side of the wafer against the past typical structure having these electrodes on the up and down-side of the wafer. Therefore, the sensor can be fabricated monolithically to be more compatible with the IC process technology, and is possible to detect more correct output capacitance by removing the effect of the parasitic capacitance from the bottom layer and other junctions. To do this, the sensor was fabricated using process such as localized formation of porous silicon, oxidation of porous silicon layer, and etching of oxidized porous silicon layer. From the completed samples, the dependence of capacitance on the relative humidity of 55 to 90% more was measured at room temperature. As the result, the measured capacitance increased monotonously higher at the low frequency of 120 Hz, where the capacitance was observed to increase over 300%.

  • PDF

Development of Humidity Sensor Based on Ceramic/Metal Halide Composite Films for Non-Contact Biological Signal Monitoring Applications (비접촉 생체신호 모니터링 응용을 위한 세라믹/메탈 할라이드 복합막 기반 습도센서 개발)

  • Park, Tae-Ung;Kim, Ik-Soo;Kim, Min-Ji;Park, Chulhwan;Seo, Eui-kyoung;Oh, Jong-Min
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
    • /
    • v.35 no.4
    • /
    • pp.412-417
    • /
    • 2022
  • Capacitive-type humidity sensors with a high sensitivity and fast response/recovery times have attracted a great attention in non-contact respiration biological signal monitoring applications. However, complicated fabrication processes involving high-temperature heat treatment for the hygroscopic film is essential in the conventional ceramic-based humidity sensors. In this study, a non-toxic ceramic/metal halide (BaTiO3(BT)/NaCl) humidity sensor was prepared at room temperature using a solvent-free aerosol deposition process (AD) without any additional process. Currently prepared BT/NaCl humidity sensor shows an excellent sensitivity (245 pF/RH%) and superior response/recovery times (3s/4s) due to the NaCl ionization effect resulting in an immense interfacial polarization. Furthermore, the non-contact respiration signal variation using the BT/NaCl sensor was determined to be over 700% by maintaining the distance of 20 cm between the individual and the sensor. Through the AD-fabricated sensor in this study, we expect to develop a non-contact biological signal monitoring system that can be applied to various fields such as respiratory disease detection and management, infant respiratory signal observation, and touchless skin moisture sensing button.