KR101698680B1 - High selective and high seneitive gas sensor device - Google Patents

High selective and high seneitive gas sensor device Download PDF

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Publication number
KR101698680B1
KR101698680B1 KR1020150119146A KR20150119146A KR101698680B1 KR 101698680 B1 KR101698680 B1 KR 101698680B1 KR 1020150119146 A KR1020150119146 A KR 1020150119146A KR 20150119146 A KR20150119146 A KR 20150119146A KR 101698680 B1 KR101698680 B1 KR 101698680B1
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South Korea
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sensor
gas
insulating layer
base
sensitivity
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KR1020150119146A
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Korean (ko)
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최경진
박원일
김수한
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울산과학기술원
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
    • G01N27/26—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating electrochemical variables; by using electrolysis or electrophoresis
    • G01N27/403—Cells and electrode assemblies
    • G01N27/406—Cells and probes with solid electrolytes
    • G01N27/407—Cells and probes with solid electrolytes for investigating or analysing gases
    • G01N27/4071—Cells and probes with solid electrolytes for investigating or analysing gases using sensor elements of laminated structure
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
    • G01N27/26—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating electrochemical variables; by using electrolysis or electrophoresis
    • G01N27/403—Cells and electrode assemblies
    • G01N27/406—Cells and probes with solid electrolytes
    • G01N27/407—Cells and probes with solid electrolytes for investigating or analysing gases
    • G01N27/4073—Composition or fabrication of the solid electrolyte
    • G01N27/4074—Composition or fabrication of the solid electrolyte for detection of gases other than oxygen
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
    • G01N27/26—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating electrochemical variables; by using electrolysis or electrophoresis
    • G01N27/403—Cells and electrode assemblies
    • G01N27/406—Cells and probes with solid electrolytes
    • G01N27/407—Cells and probes with solid electrolytes for investigating or analysing gases
    • G01N27/4075—Composition or fabrication of the electrodes and coatings thereon, e.g. catalysts

Abstract

The objective of the present invention is to provide a high selective and high sensitive gas sensor device to enhance selectivity of adsorbed gas based on a pair of sensors and have high sensitivity properties at the same time. According to the present invention, the gas sensor device comprises: a base; a bottom sensor formed on the top of the base; an insulation layer formed on the top of the bottom sensor; and a top sensor formed on the top of the insulation layer. The gas is detected by a reaction ratio between the top and bottom sensors.

Description

Technical Field [0001] The present invention relates to a high selectivity and high sensitivity gas sensor device,

The present invention relates to a high selectivity and high sensitivity gas sensor element, and more particularly to a high selectivity and high sensitivity gas sensor element having two sensor pairs.

Gas sensors that detect toxic and environmentally harmful gases are used in various fields and researches on them have been continuously carried out.

Particularly, in the case of a semiconductor type gas sensor using a metal oxide thin film as a gas sensitive substance, various studies are being conducted due to the development of the semiconductor industry.

The semiconductor type gas sensor includes a substrate, electrodes formed on the substrate, and a gas sensing layer formed on the electrode. The substrate is made of silicon or alumina, and the electrode is made of platinum or gold Of the noble metal, and the gas sensing layer is composed of a metal oxide thin film.

The semiconductor type gas sensor senses the kind and concentration of the gas by using the change in electrical resistance of the metal oxide thin film by the adsorption of the gas molecules and the oxidation / reduction reaction on the surface of the metal oxide thin film. At this time, In general, metal oxide semiconductor materials such as zinc oxide (ZnO), tin oxide (SnO2), tungsten oxide (WO3), titanium oxide (TiO2) and indium oxide (In2O3) are used.

In recent years, attempts have been made to improve the gas sensitivity through the increase of the specific surface area of the gas sensing layer. Typically, as a technique in which a gas sensing layer is formed of a nano-structure, Japanese Patent Application Laid-Open No. 2010-0067972 No. 11-0056694 discloses a semiconductor type gas sensor in which a gas sensing layer is made of nanofibers.

The semiconductor type gas sensor disclosed in the patent has a simple operation principle, a small volume, and a low manufacturing cost, so that it is highly expected that it can replace an existing electric chemical formula or optical gas sensor.

However, since the value output from the sensor is determined by the type and number of gas molecules adsorbed on the gas sensing layer, the two parameters are separated and analyzed It is difficult to achieve the above.

In order to overcome the above disadvantages, a pattern recognition method of using a sensor array coupled with a plurality of sensors and analyzing data to sort out gas molecules has been mainly used. However, since it is difficult to perform real-time monitoring and difficult to miniaturize, Is vulnerable.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a high selectivity and high sensitivity gas sensor element having high sensitivity characteristics while improving the selectivity of adsorbed gas based on two sensor pairs, .

In order to achieve the above object, the present invention provides a high selectivity and high sensitivity gas sensor element comprising: a base; A bottom sensor formed on the base top; An insulating layer formed on the upper end of the lower sensor; And an upper sensor formed on an upper end of the insulating layer, wherein gas is detected by the reaction ratio of the upper sensor and the lower sensor.

Preferably, the bottom sensor is a two-dimensional planar form of single to several atomic layer thicknesses and the material is selected from the group consisting of graphene or MX2 (M = Ti, Zr, V, Ta, Mo, W, X = And a TMDC (transition metal dichalcogenide) having a molecular formula.

Preferably, the top sensor is formed in a two-dimensional planar form of single to several atomic layer thicknesses and the material comprises graphene or TMDC.

Preferably, the insulating layer is made of an insulating material and is composed of a two-dimensional plane having a single atomic layer thickness.

More preferably, the lower sensor and the upper sensor further include a plurality of electrodes, and the lower sensor electrode and the upper sensor electrode are disposed at 90 degrees from the base plane.

The high selectivity and high sensitivity gas sensor element according to the present invention comprises a bottom sensor located at the bottom, an insulating layer located at the top of the bottom sensor, and an upper sensor located at the top of the insulating layer, Wherein the lower sensor is configured to react with a magnetic field due to polarization or ionization of gas molecules that are reacted through the upper sensor and to detect a gas by using the reaction ratio of the upper sensor and the lower sensor In the case of sensing, the reaction according to the number of gas molecules can be canceled, so that there is an effect of providing a gas sensor element that reacts only with a gas molecule type quickly and with high sensitivity.

1 is a cross-sectional view of a high-sensitivity gas sensor element according to the present invention,
Fig. 2 is a perspective view of Fig. 1,
FIG. 3 is a schematic diagram for sensing the gas of FIG. 1;

Hereinafter, preferred embodiments according to the present invention will be described in detail with reference to the accompanying drawings.

1, the high selectivity and high sensitivity gas sensor element 100 according to the present invention includes a base 1, a bottom sensor 10 positioned at the top of the base 1, a bottom sensor 10, And an upper sensor 30 positioned at an upper end of the insulating layer 20. The upper insulating layer 20 may be formed of an insulating material.

The base 1 serves to support other members, and a wiring or the like for signal output of the sensors 10 and 30 is located. The base 1 is constructed in the same manner as a normal sensor base.

The lower sensor 10 includes an electrode 11 formed at both ends and a sensing unit 12 connecting the electrode 11.

The sensing part 12 is formed in a two-dimensional planar shape having a single atomic layer thickness and the sensing part 12 is made of graphene or MX2 (M = Ti, Zr, V, Ta, X = S, Se combination) having a molecular formula of TMDC (transition metal dichalcogenide).

The sensing unit 12 is preferably made of the material described above for the purpose of reacting to an electric field generated according to polarization and ionization degree of gas molecules attached to the upper sensor 30 to be described later.

At this time, a wire to which a signal is drawn out is connected to the electrode 11.

On the other hand, the insulating layer 20 is positioned on the upper end of the lower sensor 10.

The insulating layer 20 also consists of a two dimensional plane of single atomic layer thickness.

Since the insulating layer 20 may be made of any material having electrical insulation property for maintaining electrical insulation between the upper sensor 30 and the lower sensor 10, And can be made of any material that can be formed.

On the other hand, the upper sensor 30 is positioned on the upper side of the insulating layer 20. The upper sensor 30 also includes a plurality of electrodes 31 and a sensing unit 32 connected to the plurality of electrodes 31.

The electrode 31 has a structure for external connection to the outside on the wiring, and the sensing part 32 functions to react with gas molecules.

The sensing part 32 is formed of a combination of graphene or TMDC. The sensing part 32 may be formed of a combination of graphene or TMDC. .

At this time, as shown in FIG. 2, the electrode 31 is advantageously placed in a state of being rotated by 90 degrees in order to avoid interference with the electrode 11 of the lower sensor 10.

The high selectivity and high sensitivity gas sensor element 100 according to the present invention is constituted by a double sensor structure including the upper sensor 30, the insulating layer 20 and the lower sensor 10 as described above, (20, 30) comprises a two-dimensional sensing portion (12, 32) arranged in atomic thickness.

The sensor element 100 is formed by first forming a bottom sensor 10 on a base 1 and forming an insulating layer 20 having an atomic thickness on the top of the bottom sensor 10, To form a film.

Here, in the case of the upper sensor 30 of the two sensor pairs, the sensor reacts directly with the adsorbed gas molecules, and in addition to the size and adsorption distance of the adsorbed gas molecules, the polarization degree, the charge transfer between the semiconductor and the gas molecules, The reactivity of the sensor (S Top ) is determined by the number of molecules.

In the case of the lower sensor 10, the gas molecules are not directly contacted with each other, but the reactivity (S Bottom ) of the sensor is influenced by the electric field depending on the polarization or ionization degree of the upper sensing unit 32 and the gas molecules .

 Although the reactivity is determined in proportion to the number of adsorbed molecules in both of the upper and lower sensors 30 and 20, the ratio of reactivity of the upper and lower sensors 30 and 20 is offset by the influence of the number of molecules, Regardless of the number of parameters.

Therefore, when the ratio of the reactivity of the upper and lower sensors 30 and 20 is defined as a selectivity index (a) and it is precisely measured, it can be realized as a high sensitivity sensor which responds only to the kinds of gas molecules regardless of the number of molecules.

(I) when one molecule is attached to the upper sensor 30, or (ii) when three molecules are attached to the upper sensor 30, as shown in the schematic diagram in Fig. 3, Are the same.

In the case of polar molecular adsorption (spontaneous polarization) (iii), in the case of polar molecular adsorption (iv) where the size is relatively large, when the charge transfer between adsorbed molecules and TMDC occurs (v) The degree of polarization, the charge transfer, and the like, so that the number of gas molecules is not affected.

Since the sensors 10 and 30 and the insulating layer 20 have a single atomic layer thickness, it is possible to manufacture the conventional graphene, hBN / TMDC, and graphene-hBN heterostructure ≪ / RTI >

For example, a transition metal that absorbs carbon well such as Ni, Cu, Pt and the like is prepared as a catalyst layer, and an appropriate amount of a mixed gas of CH 4 , H 2 , and Ar is introduced at a high temperature of 1,000 ° C or higher. In the mixed gas injected at high temperature, when carbon reacts with the catalyst layer and then quenched, carbon is separated from the catalyst and graphenes grow on the surface. Then, if the catalyst layer or support layer is removed by using the etching solution, graphene can be separated and transferred to a desired substrate.

Also, single-layer two-dimensional nanomaterials such as high-purity, high-performance TMDC, hBN and the like can be produced using mechanical exfoliation.

Finally, co-laminating and restacking methods are used to fabricate the heterostructure of graphene and hBN. First, hBN is transferred onto a SiO 2 substrate by mechanical peeling. Then, a water-soluble polymer is coated on another substrate, and then PMMA is coated thereon. Finally, graphene is transferred using a mechanical peeling method. The prepared substrate is placed in DI water to obtain a PMMA / Graphene layer. After transferring it onto glass, the graphene and hBN are superimposed on each other through an optical microscope, and heat is applied to the two layers. After the transcription is completed, the heterostructure of graphene and hBN is completed by removing the PMMA using acetone.

When the above method is applied, each of the sensors 10 and 30 and the insulating layer 20 of the high selectivity and high sensitivity gas sensor device 100 according to the present invention can be formed.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, And all of the various forms of embodiments that can be practiced without departing from the technical spirit.

1: Base 10: Lower sensor
11: positive 12: sensing unit
20: insulation layer 30: upper sensor
31: Electrode 32:
100: Highly sensitive gas sensor element

Claims (5)

In a high selectivity and high sensitivity gas sensor element,
Base;
A bottom sensor formed on the base top;
An insulating layer formed on the upper end of the lower sensor; And
And an upper sensor formed on an upper end of the insulating layer,
The upper sensor reacts directly with the adsorbed gas molecules and the lower sensor does not directly contact with the gas molecules but reacts with the magnetic field due to the polarization or ionization of the gas molecules reacted through the upper sensor,
Wherein the sensor detects the gas by the ratio of the reactivity of the upper sensor and the sensor of the lower sensor.
2. The method of claim 1, wherein the bottom sensor is a two-dimensional planar form of single to several atomic layer thicknesses and the material is graphene or MX2 (M = Ti, Zr, V, Ta, Mo, W, X = And a transition metal dichalcogenide (TMDC) having a molecular formula of < RTI ID = 0.0 > 1. < / RTI >
The high selectivity and high sensitivity gas sensor element of claim 1, wherein the top sensor is formed in a two-dimensional planar form of single to atomic layer thickness, and the material comprises graphene or TMDC.
The high-selectivity and high-sensitivity gas sensor element according to claim 2 or 3, wherein the insulating layer is made of an insulating material and is formed of a two-dimensional plane having a single atomic layer thickness.
The high-sensitivity and high-sensitivity gas sensor device according to claim 4, wherein the lower sensor and the upper sensor further include a plurality of electrodes, and the lower sensor electrode and the upper sensor electrode are disposed at 90 degrees from the base plane. .





KR1020150119146A 2015-08-24 2015-08-24 High selective and high seneitive gas sensor device KR101698680B1 (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114235903A (en) * 2020-09-09 2022-03-25 中国科学院苏州纳米技术与纳米仿生研究所 Gas sensor and manufacturing method thereof

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20060094664A (en) * 2005-02-25 2006-08-30 이주헌 One chip gas sensor for detecting multi gases fabricated bridge on micro channel and fabricating method of the same
KR20110000917A (en) * 2009-06-29 2011-01-06 한국과학기술연구원 Sensors for detecting temperature and multi gas and methed for manufacturing the same
KR20110056694A (en) * 2009-11-23 2011-05-31 한국전자통신연구원 Environment gas sensor and method for preparing the same
KR20140074269A (en) * 2011-06-08 2014-06-17 알파 모스 에스.아. Chemoresistor type gas sensor having a multi-storey architecture

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20060094664A (en) * 2005-02-25 2006-08-30 이주헌 One chip gas sensor for detecting multi gases fabricated bridge on micro channel and fabricating method of the same
KR20110000917A (en) * 2009-06-29 2011-01-06 한국과학기술연구원 Sensors for detecting temperature and multi gas and methed for manufacturing the same
KR20110056694A (en) * 2009-11-23 2011-05-31 한국전자통신연구원 Environment gas sensor and method for preparing the same
KR20140074269A (en) * 2011-06-08 2014-06-17 알파 모스 에스.아. Chemoresistor type gas sensor having a multi-storey architecture

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114235903A (en) * 2020-09-09 2022-03-25 中国科学院苏州纳米技术与纳米仿生研究所 Gas sensor and manufacturing method thereof

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