• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.11a
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• pp.448-451
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• 2004

Vanadium oxides have been widely used in a variety of technological applications such electrochromic devices as infrared detectors and are expected as a material suitable for gas sensing applications. Thin films of Vanadium oxide (VOx) have been deposited by r.f magnetron sputtering under different oxygen partial pressure ratios and substrate temperatures. Humidity-sensitive properties of resistive sensors having interdigitated electrode structure are characterized. Our sensors show good response to humidity over 20%RH to 80%RH. Vanadium oxide films deposited with 0% $O_2$ partial pressure at foot exhibit greater sensitivity to humidity change than others.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.45 no.1
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• pp.93-99
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• 1996

The formation properties and oxidation mechanism of electrochemically oxidized porous silicon(OPS) films have been studied. To examine the humidity-sensitive properties of OPS films, surface-type and bulk-type humidity sensors were fabricated. The oxidized thickness of porous silicon layer(PSL) increases with the charge supplied during electrochemical humidity sensor shows high sensitivity at high relative humidity in low temperature. The sensitivity and linearity can be improved by optimizing a porosity of PSL. (author). refs., figs.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.14 no.4
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• pp.302-308
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• 2001

The polymers with various composition of 4-vinylpyridine (4-VP) with n-butyl acrylate (n-BA) and 2-hydroxypropyl methacrylate (HPMA) were synthesized as a humidity sensitive material and quaternized with 1.5-dibromopentane. Resistance versus relative humidity decreased with increase in the content of n-BA in the copolymer. The introduction of HPMA increased the resistance of the humidity sensor as well as enhanced the adherence to the alumina substrate. In the case of 4-VP/n-BA/HPMA=80/10.10, the hysteresis and temperature coefficient were $\pm$2%RH and -0.42∼0.46%RH/$\^{C}$. The average resistance at 30%RH, 60%RH and 90%RH are 3.1㏁, 155 ㏀ and 7.9 ㏀, respectively.

• Proceedings of the KIEE Conference
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• 1995.07c
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• pp.1066-1068
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• 1995

The formation properties and oxidation mechanism of electrochemically oxidized porous silicon(OPS) films have been studied. To examine the humidity-sensitive properties of OPS films, surface-type and bulk-type humidity sensors were fabricated. The oxidized thickness of porous silicon layer(PSL) increases with the charge supplied during electrochemical oxidation and current density. The humidity sensor shows high sensitivity at high relative humidity in low temperature. The sensitivity and linearity can be improved by increasing a porosity of PSL.

• Macromolecular Research
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• v.12 no.3
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• pp.311-315
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• 2004

We have prepared new polyelectrolytes containing trialkoxysilyl groups by copolymerizing 3-(trimethoxysilyl)propyl methacrylate (TSPM) with either [2-(methacryloyloxy)ethyl]trimethyl ammonium chloride (METAC), [2-(methacryloyloxy)ethyl]dimethyl propyl ammonium bromide (MEDPAB), or [2-(acryloyloxy)ethyl]trimethyl ammonium chloride (AETAC). The copolymers TSPM/METAC, TSPM/MEDPAB, and TSPM/METAC having compositions of 15/85, 10/90, and 5/95, respectively, were self-crosslinkable polyelectrolytes that possess humidity-sensitive properties. We measured the impedances of the copolymers at various relative humidities (RHs) and found that the resistance was dependent on the content of METAC, MEDPAB, or AETAC. The impedance changed from 10$\^$7/ $\Omega$ at 20% RH to 10$^3$ $\Omega$ at 95% RH, which is quite a suitable range for a humidity sensor that is to be utilized at ambient humidity. We also performed tests of the materials temperature dependence, hysteresis, response time, and water durability.

• Journal of Sensor Science and Technology
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• v.5 no.3
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• pp.33-40
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• 1996

$(Ba_{0.5}\;Ca_{0.5})TiO_{3}$ humidity-sensitive devices were fabricated by a solid reaction method, and their electrical properties were investigated. The specimens exhibited good humidity sensitivity, in which the impedance changes linearly. It is shown that electrical conduction with moisture adsorption is dominated by the ions through characteristics of charging and discharing current, and electrical conductivity increases as rasing the temperature and relative humidity. It is realized that relative permittivity increases and activation energy decreases with increasing relative humidity.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.11a
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• pp.247-248
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• 2006

Carbon nitride films were evaluated that they had many advantages for miniature micro-humidity-sensors using the standard CMOS technology humidity sensing properties and CV characteristics of the carbon nitride films have been investigated for fabricating one chip HUSFET(Humidity Sensitive Field Effect Transistor) humidity sensors Carbon nitride films were deposited on silicon substrate with meshed electrodes by reactive RF magnetron sputtering system. The capacitor-type humidity sensor revealed good humidity-impedance characteristics with a wide range of relative humidity changes, decreasing $254k{\Omega}$ to $16k{\Omega}$ according to increase of relative humidity between 5% ~ 95% and the films were very stable on the Si wafer. These results reveal that $CN_x$ thin films can be used for Si based or HUSFET structure one chip micro-humidity sensors.

• Macromolecular Research
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• v.16 no.4
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• pp.308-313
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• 2008

A simple strategy was developed based on polyelectrolyte/silver nanocomposite to obtain humidity-sensitive membranes. The major component of a humid membrane is the polyTEAMPS/silver nanocomposite obtained by thermal heating the mixture of a polyelectrolyte and silver isopropylcarbamate complex. Humidity sensors prepared from polyTEAMPS/silver (w/w=100/0 and 100/6) nanocomposites had an average impedance of 292, 8.83 and $0.86\;k{\Omega}$, and 5,327, 140 and $0.93\;k{\Omega}$ at 30,60 and 95% relative humidity (RH), respectively. Hysteresis, temperature dependence and response time were also measured. Activation energies and complex impedance spectroscopy of the various components of the polyelectrolyte/silver nanocomposite films were examined for the humidity-sensing membrane.

• Proceedings of the KIEE Conference
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• 1996.07c
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• pp.1728-1731
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• 1996

To develop more sensitive humidity sensor on high temperature region, in this paper, we prepared polyimide humidity sensor by electrophoretic method. Sensing properties of be sensor in high temprature region were studied and compared with that prepared by solution casting method. From the result, the thiner film thickness, the more sensitive. however, It is difficult to make he thickness optimal because of short between electrodes, and the thickness of upper electrode is one of most important parameters affecting pefomance of the sensor.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.5
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• pp.521-525
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• 2004

Crystalline carbon nitride films were attempted for an application of humidity sensors. The films were deposited on $Al_2$O$_3$substrate having intermigrated electrodes by reactive rf magnetron sputtering system. The film revealed a good humidity-resistance characteristics as well as humidity-capacitance ones in the humidity range of 10∼95 RH(%). Temperature dependence was also investigated. These results suggest that the carbon nitride film has a possibility for new humidity-sensitive material.