JP2006315933A - Organic inorganic hybrid thin film and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electroconductive organic inorganic hybrid thin film mainly composed of molybdenum oxide (MoO<SB>3</SB>) and formed on a silicon substrate, a manufacturing method of the thin film, and a sensor member etc., utilizing the electroconductive organic inorganic hybrid thin film. <P>SOLUTION: This electroconductive organic inorganic hybrid thin film is an organic inorganic hybrid thin film formed on a silicon substrate, which is less expensive compared with a metal oxide single crystal, through an appropriate buffer layer of a metal oxide formed on the substrate, and its manufacturing method is also provided. This chemical sensor member uses the electroconductive organic inorganic hybrid thin film made by the method as a sensor element, and it responds highly sensitively to a gas of VOC, etc. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an organic-inorganic hybrid thin film, a method for producing the same, and an application thereof. More specifically, the present invention relates to an organic-inorganic hybrid thin film element in which an organic-inorganic hybrid thin film is formed on a silicon single crystal substrate. In the technical field of a gas sensor using a high-performance hybrid material in which an organic compound and an inorganic compound are combined at a nano level, the present invention has a problem that an expensive metal oxide single crystal substrate is required for a conventional hybrid thin film. In view of the above, the present inventors have established a technique for forming an organic-inorganic hybrid thin film on an inexpensive silicon single crystal substrate by interposing a buffer layer made of a metal oxide on the silicon single crystal substrate. The present invention relates to a novel conductive organic-inorganic hybrid thin film capable of producing a high-quality conductive organic-inorganic hybrid thin film that can be used as an electronic device material on a silicon substrate, a production method thereof, and a product thereof, An electroconductive member and a chemical sensor member are provided.

  Organic-inorganic hybrid material is an unprecedented new material that combines the excellent heat resistance and mechanical strength of inorganic compounds with the excellent chemical properties of organic compounds. Optical and electrical properties In addition, the hybrid material is expected to be applied to various fields because it has a characteristic function in mechanical characteristics and the like. Among them, an organic-inorganic hybrid material exhibiting electrical conductivity has been reported to have high potential for application to, for example, light-emitting elements, transistors, batteries, chemical sensors, and the like.

The organic / inorganic hybrid material has a function that can convert chemical information, such as the presence or absence of an organic compound having a molecular recognition function and a gas to be detected, into an electrical signal and output it to the outside. It has been reported that the use of a hybrid material in which an inorganic compound is compounded at a nano level is effective in improving gas selectivity (Non-patent Document 1). As a specific example, in an intercalation type organic-inorganic hybrid material in which molybdenum oxide (MoO ₃ ) having a layered structure is a main component and an organic compound is inserted between molybdenum oxide layers, the material is a volatile organic compound. Responds to (VOC) by changing the resistance value, and hardly responds to toluene and benzene, whereas it selectively responds to aldehydes, alcohols, and chlorine-based gases. A chemical sensor element made of the material has been proposed by utilizing the gas selectivity (Patent Document 1).

Development of thin film technology is indispensable for the application of organic-inorganic hybrid materials to devices. However, the intercalation-type organic-inorganic hybrid materials are already (1) highly oriented inorganic compounds with a layered structure. A method for producing a high-quality thin film has been developed by a method characterized in that a thin film is produced, (2) hydrated sodium ions are intercalated in the highly oriented thin film, and (3) this is replaced with an organic compound. It has been reported (Patent Document 2) that the thin film functions as a VOC gas sensor (Patent Document 3 and Non-Patent Documents 2 and 3). However, the production of the thin film requires an expensive metal oxide single crystal substrate such as LaAlO _{3. In} this technical field, in order to realize the application of the hybrid material to a sensor device, inexpensive silicon Development of thin film manufacturing technology on a substrate is an urgent issue.

JP 2004-271482 A Japanese Patent Application No. 2003-422141 Japanese Patent Application No. 2004-140528 Chemical sensor, vol. 20, no. 3,106 (2004) Proc. MRS 2003 Fall Meeting, 785, D14.9.1-6 (2004) Chem. Mater. , Vol. 17, 349 (2005)

  Under such circumstances, the present inventors have aimed at developing a method for producing a conductive organic-inorganic hybrid thin film mainly composed of molybdenum oxide on a silicon substrate in view of the above-described conventional technology. As a result of extensive research, a metal oxide with a lattice constant similar to that of molybdenum oxide was used as the buffer layer, and then a highly oriented film of molybdenum oxide prepared by CVD was first intercalated with hydrated sodium ions. Furthermore, an organic-inorganic hybrid thin film can be obtained by a method of substituting with a conductive polymer or organic ions, and the obtained thin film is converted into a VOC gas as in the case of using a metal oxide single crystal substrate. On the other hand, the present inventors have found that it responds by changing the resistance value, and completed the present invention.

  The present invention relates to a conductive organic-inorganic hybrid thin film that can be used as an electro device material, a method for producing a conductive organic-inorganic hybrid thin film that enables the production of the hybrid thin film, and applied products thereof, in particular, conductive members, An object of the present invention is to provide a high-sensitivity chemical sensor member.

The present invention for solving the above-described problems comprises the following technical means.
(1) An organic-inorganic hybrid thin film comprising a silicon single crystal substrate and an organic-inorganic hybrid thin film formed on the substrate with a metal oxide buffer layer interposed therebetween.
(2) The organic-inorganic hybrid thin film is obtained by intercalating a hydrated alkali metal ion into a highly oriented thin film of an inorganic compound having a layered structure, and further substituting it with an organic compound. Organic inorganic hybrid thin film.
(3) The organic-inorganic hybrid thin film according to (1), wherein the organic-inorganic hybrid thin film is mainly composed of molybdenum oxide.
(4) The organic-inorganic hybrid thin film according to (1) or (2), wherein the organic-inorganic hybrid thin film contains a conductive polymer.
(5) The organic-inorganic hybrid thin film according to (1) or (2), wherein the organic-inorganic hybrid thin film contains organic ions.
(6) The organic-inorganic hybrid thin film according to (1), wherein the buffer layer is a metal oxide having a lattice constant similar to molybdenum oxide.
(7) In a method of manufacturing an organic-inorganic hybrid thin film in which an organic-inorganic hybrid thin film is formed on a silicon single crystal substrate, the organic-inorganic hybrid thin film is interposed on the silicon single crystal substrate with a buffer layer made of a metal oxide. A method for producing an organic-inorganic hybrid thin film characterized by growing.
(8) The organic material according to (7), wherein a highly oriented thin film of an inorganic compound having a layered structure is intercalated with a hydrated alkali metal ion and further substituted with an organic compound to grow an organic-inorganic hybrid film. Manufacturing method of inorganic hybrid thin film.
(9) A conductive member comprising the organic-inorganic hybrid thin film according to any one of (1) to (6) as a constituent element.
(10) A chemical sensor member comprising the organic-inorganic hybrid thin film according to any one of (1) to (6) as a sensor element.

Next, the present invention will be described in more detail.
As described above, the present invention forms a highly oriented molybdenum oxide thin film by a CVD method on a silicon single crystal substrate provided with a metal oxide having a lattice constant similar to that of molybdenum oxide as a buffer layer. After intercalating, a conductive intercalated organic-inorganic hybrid thin film is produced by substituting this with an organic compound.

  In the present invention, an organic-inorganic hybrid thin film can be manufactured on an inexpensive silicon single crystal substrate by employing the above-described specific configuration. The present invention is achieved by using a metal oxide having a lattice constant similar to molybdenum oxide, which is an inorganic component of an organic-inorganic hybrid, as a buffer layer on a silicon single crystal substrate. When a silicon single crystal substrate without a buffer layer is used, there is a problem that the thin film is peeled off from the substrate in the process of intercalating hydrated alkali metal ions to the molybdenum oxide thin film produced by the CVD method.

  When a metal oxide single crystal substrate is used, such a problem does not occur. Therefore, an appropriate metal oxide buffer layer is formed on a silicon single crystal substrate, and an organic-inorganic hybrid thin film is formed thereon by the above process. It is considered that the problem of peeling can be avoided if formed. It is desirable that the metal oxide employed as the buffer layer has a lattice constant similar to that of molybdenum oxide, which is an inorganic layer.

In the step of intercalating an organic substance into molybdenum oxide having a layered structure, the interlayer distance of molybdenum oxide increases. For this reason, the molybdenum oxide thin film needs to be oriented so that the layer direction (ac surface) is parallel to the substrate surface (b-axis orientation). When intercalation is performed on a molybdenum oxide thin film in which such orientation is not realized, the film is peeled off from the substrate due to distortion caused by an increase in interlayer distance. In order to realize the b-axis orientation, it is desirable that the average axial length of the a-axis and the c-axis of molybdenum oxide that is orthorhombic is similar to the lattice constant of the substrate. Actually, the lattice constant mismatch with the (100) plane of LaAlO ₃ used as the metal oxide single crystal substrate is about 1%.

From the above, examples of the metal oxide employed as the buffer layer include metal oxides having a perovskite structure such as LaAlO ₃ and metal oxides such as CeO ₂ having a fluorite structure. It is not limited to. As described above, in the present invention, the buffer layer is originally oriented by being formed on the surface of the silicon substrate having a large lattice constant mass match with molybdenum oxide and being difficult to form an oriented molybdenum oxide thin film. It serves as a template for growing the molybdenum oxide thin film, and as a result, the hybrid thin film can be formed on the silicon substrate without peeling.

The method for forming the buffer layer is not particularly limited as long as a dense and homogeneous film can be obtained on the silicon single crystal substrate. In the present invention, a solution method and a sputtering method are employed. A detailed buffer layer forming process by the solution method is shown below. When LaAlO ₃ is used as a buffer layer, a commercially available La solution and Al solution are mixed so that La: Al = 1: 1 and sufficiently stirred. The total metal ion concentration is about 0.05 M / L. This solution is spin-coated on a silicon single crystal substrate. The conditions for spin coating are not particularly limited as long as a uniform film is formed, but as an example, it is 30 seconds at 2000 rpm.

Next, the substrate coated with the solution is heat-treated in air. The heat treatment temperature is usually 800 to 1100 ° C, preferably 900 to 1000 ° C. The heat treatment time is usually 10 to 60 minutes, preferably 20 to 40 minutes. When CeO ₂ is used as the buffer layer, a commercially available Ce solution is spin-coated by the same method as described above, and heat treatment is performed. The Ce ion concentration in the solution is about 0.05 M / L. The heat treatment temperature is usually 500 to 800 ° C, preferably 600 to 700 ° C. The heat treatment time is usually 10 to 60 minutes, preferably 20 to 40 minutes.

  It can be confirmed that all diffraction peaks observed in the X-ray diffraction pattern of the buffer layer produced under the above-described conditions are attributed to the target metal oxide phase. Furthermore, from the observation with a scanning electron microscope, the buffer layer has a thickness of 50 to 100 nm, and it can be confirmed that the buffer layer is uniformly and densely formed on the entire substrate.

When producing an organic-inorganic hybrid thin film on the buffer layer, (1) preparation of highly oriented thin film of molybdenum oxide (MoO ₃ ), (2) intercalation of hydrated alkali ions into the molybdenum oxide thin film, (3) A three-step process of substitution reaction between hydrated alkali ions and conductive polymer or organic ions is performed. Hereinafter, each process will be described in detail.

The method for forming molybdenum oxide in the step (1) is not particularly limited as long as a highly oriented film can be obtained. In the present invention, a CVD method is preferably employed. For the molybdenum source in the CVD method, hexacarbonyl molybdenum Mo (CO) ₆ is preferably used in the present invention.

Next, in step (2), hydrated alkali ions are intercalated into the molybdenum oxide thin film. After bubbling distilled water with argon gas for about 10 minutes, sodium dithionite (Na ₂ S ₂ O ₄ ) and sodium molybdate (Na ₂ MoO ₄ ) are added and dissolved by stirring. The molybdenum oxide oriented thin film produced in step (1) is immersed here. The immersion time is usually about 5 to 120 seconds, preferably about 10 to 60 seconds. During this time, the colorless molybdenum oxide thin film turns blue, and it can be confirmed that molybdenum oxide is reduced and hydrated sodium ions are intercalated.

After immersion, the thin film is quickly washed with distilled water and dried to obtain a [Na (H ₂ O) ₂ ] _x MoO ₃ thin film in which hydrated sodium ions are intercalated between the molybdenum oxide layers. The progress of the intercalation reaction can be confirmed from the X-ray diffraction pattern. Due to the intercalation of hydrated sodium ions, the molybdenum oxide layer spreads, and the diffraction peak indexed at (0k0) shifts to the lower angle side.

Next, in step (3), a substitution reaction between the hydrated alkali ion and the conductive polymer or organic ion is performed. In a substitution reaction with polypyrrole (PPy), which is a typical conductive polymer, pyrrole is first added to distilled water, and after sufficiently stirring and mixing using an ultrasonic homogenizer, an oxidizing agent is added and further stirred. The [Na (H ₂ O) ₂ ] _x MoO ₃ thin film prepared in the step (2) is immersed here. The immersion time is usually 3 seconds to 5 minutes, preferably about 10 to 60 seconds. The (PPy) _x MoO ₃ thin film is obtained by taking out the thin film, washing and drying.

The oxidizing agent used here is not particularly limited as long as it can oxidize pyrrole, and examples thereof include iron chloride, ammonium peroxodisulfate, and iron nitrate. The amount of pyrrole added is usually 50 to 200 times equivalent, preferably 100 to 150 times equivalent to [Na (H ₂ O) ₂ ] _x MoO ₃ . The addition amount of the oxidizing agent is usually 1 to 3 times equivalent, preferably 1.5 to 2 times equivalent to [Na (H ₂ O) ₂ ] _x MoO ₃ .

In the substitution reaction with organic ions, for example, when butyl ammonium ions (C ₄ H ₉ NH ₃ ⁺ ) are used as organic ions, first, butyl ammonium chloride (C ₄ H ₉ NH ₃ Cl) is dissolved in distilled water. Here, the [Na (H ₂ O) ₂ ] _x MoO ₃ thin film is immersed. The immersion time is usually about 3 seconds to 10 minutes, preferably about 5 to 60 seconds. The (C ₄ H ₉ NH ₃ ) _x MoO ₃ thin film is obtained by taking out the thin film, washing and drying. The addition amount of C ₄ H ₉ NH ₃ Cl is usually 1 to 10 times equivalent, preferably 2 to 7 times equivalent to [Na (H ₂ O) ₂ ] _x MoO ₃ .

  Using the silicon single crystal substrate on which the gold electrode was previously deposited on the buffer layer, the sensor characteristics of the produced sensor element with respect to the VOC gas were evaluated through the above process. Usually, a resistance change type sensor made of an existing n-type semiconductor oxide responds to a VOC gas when the resistance value decreases. However, the intercalation type organic / inorganic hybrid thin film sensor obtained by the present invention has a VOC gas in any sample including those composed of a conductive polymer as an organic substance and those composed of an organic ion as an organic substance. Responds by increasing the sensor resistance.

  In the method for producing an organic-inorganic hybrid thin film on a silicon single crystal substrate having a buffer layer according to the present invention, the same method as that in the case of using the above molybdenum oxide and polypyrrole or butylammonium ion, molybdenum oxide and polypyrrole, Alternatively, the present invention can also be applied to layered inorganic compounds other than butylammonium ions, conductive polymers, or organic ions.

  Examples of the layered inorganic compound that can form a gas sensor using an organic-inorganic hybrid thin film include tungsten oxide, vanadium oxide, niobium oxide, ruthenium chloride, iron oxychloride, molybdenum sulfide, and the like, and examples of the conductive polymer include polyaniline, Polythiol, polyethylene oxide, etc., and organic ions include, for example, tetrabutylammonium ion, dodecyltrimethylammonium ion, etc., but are not limited thereto, and may be the same or similar to these. Can be used as well.

  According to the present invention, (1) it is possible to manufacture a conductive organic-inorganic hybrid thin film on an inexpensive silicon substrate by forming an appropriate buffer layer on the silicon substrate. The manufacturing cost of the inorganic hybrid sensor element can be significantly reduced. (3) The technology established in the silicon semiconductor field can be applied, and the sensor element can be miniaturized. (4) The element is formed on the silicon wafer. By doing so, the special effect that mass production becomes possible is produced.

  EXAMPLES Next, although this invention is demonstrated concretely based on an Example, this invention is not limited at all by the following Examples.

(1) Formation of CeO ₂ buffer layer by solution method The Ce ion concentration of a commercially available Ce solution was adjusted to 0.05 M / L. This solution was coated on the surface of a silicon single crystal substrate of about 10 mm square by spin coating. The spin coating conditions were 2000 rpm and 30 seconds. The substrate coated with the solution was heat-treated at 700 ° C. for 30 minutes in air. The X-ray diffraction pattern of the obtained buffer layer is shown in FIG. Only the (200) peak of the CeO ₂ phase was observed, and it was confirmed that an oriented CeO ₂ film was formed. An electron micrograph of the CeO ₂ buffer layer surface is shown in FIG. It can be seen that the film is dense and homogeneous. The film thickness was 70 nm.

(2) The production of film forming MoO ₃ thin MoO ₃ film, CVD is used. The substrate was set in a holder having a heater for heating. A molybdenum source, 0.2 g of hexacarbonylmolybdenum (Mo (CO) ₆ ), was placed in a quartz glass boat, set in a source chamber, and the source chamber was brought to 40 ° C. Oxygen gas (150 ml / min) was passed through the entire system including the sample chamber and the source chamber, the sample chamber portion was heated to 460 ° C. by an electric furnace, and the substrate temperature was further raised to 500 ° C. by a substrate heating heater. After the substrate temperature was stabilized, the entire system was evacuated with a vacuum pump, and the degree of vacuum was adjusted to 0.8 Torr. After film formation for 15 minutes, the entire system was returned to atmospheric pressure. Thereby, volatilization of the source was suppressed and film formation was completed. The X-ray diffraction patterns of the obtained buffer layer and MoO ₃ thin film are shown in FIG. Except for the peak from the substrate, the observed diffraction peak can be indexed to (0k0) of MoO ₃ having a layered structure, and it can be seen that the b-axis alignment film of MoO ₃ has grown.

(3) Intercalation of hydrated sodium ions After 25 ml of distilled water was bubbled with argon gas for 20 minutes, sodium dithionite Na ₂ S ₂ O ₄ (0.4 g, 2.2 mmol) and sodium molybdate Na ₂ MoO ₄ 2H ₂ O (6 g, 24.8 mmol) was added and dissolved by stirring. Here, the MoO ₃ thin film obtained in the above (2) was immersed for 40 seconds. During this time, the colorless molybdenum trioxide thin film turned blue. After immersion, the thin film was washed with distilled water and dried in air at 85 ° C. for about 30 minutes.

The X-ray diffraction pattern of this thin film sample is shown in FIG. Peaks indexed at (0k0) are observed, but these peaks are shifted to a lower angle side compared to MoO ₃ , and it can be seen that the interlayer distance is increased. The interlayer distance obtained from FIG. 1C is 0.97 nm, which is an increase of 0.28 nm compared to the interlayer distance of MoO ₃ (0.69 nm). The spread of the interlayer distance corresponds to the case where the hydrated sodium ion Na (H ₂ O) ₂ is intercalated, so that a [Na (H ₂ O) ₂ ] _x MoO ₃ thin film is generated. It could be confirmed.

(4) _(PPy) x to MoO ₃ in the manufacturing of distilled water 25mL of thin, pyrrole (2.0 ml, 28.9 mmol) was added and after 3 minutes with an ultrasonic homogenizer, iron chloride FeCl ₃ as an oxidizing agent (0 0.086 g, 0.51 mmol) was added, and the mixture was stirred at room temperature for 10 minutes. Here, the [Na (H ₂ O) ₂ ] _x MoO ₃ thin film was immersed for 2 minutes. Here, the thin film was taken out, washed with distilled water, and dried in air at 80 ° C. for about 20 minutes. The X-ray diffraction pattern of this thin film sample is shown in FIG.

Peaks indexed at (0k0) are observed, but these peaks are shifted to a lower angle side than [Na (H ₂ O) ₂ ] _x MoO ₃ , and the interlayer distance increases. I understand that The interlayer distance obtained from FIG. 1D is 1.31 nm, which is an increase of 0.62 nm compared to the interlayer distance of MoO ₃ (0.69 nm). Since the spread of the interlayer distance corresponds to the case where polypyrrole is intercalated, it was confirmed that a (PPy) _x MoO ₃ thin film was formed.

(5) Evaluation of electrical characteristics and sensor characteristics The sensor characteristics of the (PPy) _x MoO ₃ thin film sensor with respect to acetaldehyde gas were evaluated by changes in electrical resistance values. FIG. 3 shows the response to 30 ppm acetaldehyde gas. It was confirmed that the response was reversible by changing the resistance value.

In this example, a CeO ₂ buffer layer was produced by a CVD method. The MoO ₃ thin film, [Na (H ₂ O) ₂ ] _x MoO ₃ thin film, and (PPy) _x MoO ₃ thin film were produced according to the method of Example 1. FIG. 4 shows an X-ray diffraction pattern of CeO ₂ produced by the CVD method. CeO ₂ (200) and (311) peaks were observed, confirming the formation of CeO ₂ . FIG. 5 shows X-ray diffraction patterns of the [Na (H ₂ O) ₂ ] _x MoO ₃ thin film and the (PPy) _x MoO ₃ thin film prepared on the CeO ₂ buffer layer. Formation of a [Na (H ₂ O) ₂ ] _x MoO ₃ thin film and a (PPy) _x MoO ₃ thin film can be confirmed.

In this example, a CeO ₂ buffer layer was produced by a sputtering method. Sputtering was performed at a substrate temperature of 150 ° C., and then heat treatment was performed in air at 800 ° C. for 30 minutes. Preparation of the MoO ₃ thin film, [Na (H ₂ O) ₂ ] _x MoO ₃ thin film, and (PPy) _x MoO ₃ thin film was performed according to the method of Example 1. FIG. 6 shows X-ray diffraction patterns of CeO ₂ thin film, MoO ₃ thin film, [Na (H ₂ O) ₂ ] _x MoO ₃ thin film, and (PPy) _x MoO ₃ thin film prepared by sputtering. As in the case of Example 1, it was confirmed that a (PPy) _x MoO ₃ thin film was formed.

In this example, butylammonium ions (C ₄ H ₉ NH ₃ ⁺ ), which are organic ions, were intercalated between MoO ₃ layers on a CeO ₂ buffer layer prepared by a solution method (C ₄ H ₉ NH ₃ ). _{x A} MoO ₃ thin film was prepared. A [Na (H ₂ O) ₂ ] _x MoO ₃ thin film was produced according to the method of Example 1. Furthermore, in an aqueous solution prepared by dissolving [Na (H ₂ O) ₂ ] _x MoO ₃ thin film, 0.13 g (1.2 mmol) of butylammonium chloride (C ₄ H ₉ NH ₃ Cl) in 20 ml of distilled water. For 1 minute. The thin film was taken out, washed with distilled water, and dried in air at 80 ° C. for about 15 minutes. FIG. 7 shows the X-ray diffraction patterns of the [Na (H ₂ O) ₂ ] _x MoO ₃ thin film and the (C ₄ H ₉ NH ₃ ) _x MoO ₃ thin film.

In the (C ₄ H ₉ NH ₃ ) _x MoO ₃ thin film, a peak indexed by (0k0) is also observed, but these peaks are compared with [Na (H ₂ O) ₂ ] _x MoO _3. It can be seen that the distance between the layers is shifted to a lower angle side, and the interlayer distance is increased. The interlayer distance obtained from FIG. 7B is 1.18 nm, which is an increase of 0.49 nm compared to the interlayer distance of MoO ₃ (0.69 nm). Since the spread of the interlayer distance corresponds to the case where butylammonium ions are intercalated, it was confirmed that a (C ₄ H ₉ NH ₃ ) _x MoO ₃ thin film was formed.

The sensor characteristics of the (C ₄ H ₉ NH ₃ ) _x MoO ₃ thin film sensor with respect to formaldehyde gas were evaluated by changes in the electrical resistance value (FIG. 8). The (C ₄ H ₉ NH ₃ ) _x MoO ₃ thin film sensor also responded by increasing the resistance value to formaldehyde gas, as in the case of the (PPy) _x MoO ₃ thin film sensor.

In this example, a (PPy) _x MoO ₃ thin film was produced on a LaAlO ₃ buffer layer produced by a solution method. Commercially available Al solution and La solution were mixed so that the ratio of La: Al = 1: 1. Furthermore, the metal ion concentration of the solution was adjusted to 0.05 M / L. This solution was coated on the surface of a square silicon single crystal substrate of about 10 mm by spin coating. The spin coating conditions were 2000 rpm and 30 seconds. The substrate coated with the solution was heat-treated in air at 1000 ° C. for 30 minutes. An SEM photograph of the obtained buffer layer is shown in FIG. It can be seen that a uniform film is formed. The film thickness was about 70 nm.

A MoO ₃ thin film, a [Na (H ₂ O) ₂ ] _x MoO ₃ thin film, and a (PPy) _x MoO ₃ thin film were produced on the LaAlO ₃ buffer layer produced by the solution method by the method according to Example 1. . Each X-ray diffraction pattern is shown in FIG. Than the size of each interlayer distance, MoO _{3 film,} it was confirmed that the generated is _{[Na (H 2 O) 2} ] x MoO 3 thin film, and _(PPy) x MoO ₃ thin film.

The sensor characteristics of the (PPy) _x MoO ₃ thin film sensor with respect to acetaldehyde gas were evaluated by changes in the electric resistance value. FIG. 11 shows the response to 6 ppm acetaldehyde gas. It was confirmed that the response was reversible by changing the resistance value.

In this example, butylammonium ions (C ₄ H ₉ NH ₃ ⁺ ), which are organic ions, were intercalated between MoO ₃ layers on a LaAlO ₃ buffer layer prepared by a solution method (C ₄ H ₉ NH ₃ ). _{x A} MoO ₃ thin film was prepared. In accordance with the method of Example 5, the LaAlO ₃ buffer layer was formed in accordance with the method of Example 1, and the MoO ₃ thin film and [Na (H ₂ O) ₂ ] _x MoO ₃ thin film were formed in accordance with the method of Example 4. , (C ₄ H ₉ NH ₃ ) _x MoO ₃ thin films were respectively prepared. FIG. 12 shows X-ray diffraction patterns of the [Na (H ₂ O) ₂ ] _x MoO ₃ thin film and the (C ₄ H ₉ NH ₃ ) _x MoO ₃ thin film prepared on the LaAlO ₃ buffer layer. Formation of [Na (H ₂ O) ₂ ] _x MoO ₃ thin film and (C ₄ H ₉ NH ₃ ) _x MoO ₃ thin film was confirmed.

In this example, a polyaniline (PANI), which is a polymer, was intercalated between MoO ₃ layers on a LaAlO ₃ buffer layer produced by a solution method, and a (PANI) _x MoO ₃ thin film was produced. A LaAlO ₃ buffer layer was prepared in accordance with the method of Example 5, and a MoO ₃ thin film and a [Na (H ₂ O) ₂ ] _x MoO ₃ thin film were prepared in accordance with the method of Example 1. PANI intercalation was performed by the following method.

Aniline (1.5 ml) was added to 15 mL of distilled water bubbled with argon gas, and the pH was adjusted to 1.0 with hydrochloric acid. Further, here, a polymerization initiator _{(NH 4) 2 S 2 O} 8 was added 0.05 g, was stirred for 30 minutes. The above [Na (H ₂ O) ₂ ] _x MoO ₃ thin film was immersed therein for 30 seconds, washed with distilled water and acetone, and dried at 80 ° C. for about 30 minutes. FIG. 13 shows X-ray diffraction patterns of the [Na (H ₂ O) ₂ ] _x MoO ₃ thin film and the (PANI) _x MoO ₃ thin film prepared on the LaAlO ₃ buffer layer. Formation of [Na (H ₂ O) ₂ ] _x MoO ₃ thin film and (PANI) _x MoO ₃ thin film was confirmed.

  As described above in detail, the present invention relates to an organic-inorganic hybrid thin film and a method for producing the same, and according to the present invention, by forming a suitable metal oxide buffer layer on a silicon substrate, the conductivity is improved. The organic-inorganic hybrid thin film can be manufactured on an inexpensive silicon substrate. Thereby, in the present invention, a technology established in the silicon semiconductor field can be applied, the sensor element can be downsized, and the manufacturing cost of the organic-inorganic hybrid sensor element can be significantly reduced. Further, according to the present invention, elements can be formed on a silicon wafer, thereby enabling mass production. The present invention is useful, for example, as providing a new technology for widely spreading chemical sensors that exhibit excellent selectivity for VOCs.

(A) CeO ₂ buffer layer, (b) MoO ₃ thin film, (c) [Na (H ₂ O) ₂ ] _x MoO ₃ thin film, and (d) (PPy) _x MoO ₃ thin film shown in Example 1 It is a figure which shows the X-ray-diffraction pattern of. 3 is a diagram showing a scanning electron micrograph of the CeO ₂ buffer layer surface shown in Example 1. FIG. It is a diagram showing the sensor response to 30ppm formaldehyde gas _(PPy) x MoO ₃ film shown in Example 1. 6 is a diagram showing an X-ray diffraction pattern of a CeO ₂ buffer layer shown in Example 2. FIG. Shown in Example 2, a diagram illustrating the _{(a) [Na (H 2} O) 2] x MoO 3 thin film, and _{(b) (PPy) x MoO} 3 film, the X-ray diffraction pattern. Example 3 (a) CeO ₂ buffer layer, (b) MoO ₃ thin film, (c) [Na (H ₂ O) ₂ ] _x MoO ₃ thin film, and (d) (PPy) _x MoO ₃ thin film, It is a figure which shows the X-ray-diffraction pattern of. Shown in Example 4, is a diagram showing _{(a) [Na (H 2} O) 2] x MoO 3 thin film, and _{(b) (C 4 H 9} NH 3) x MoO 3 film, the X-ray diffraction pattern . Is a diagram showing the sensor response for Example 4 are shown _{(C 4 H 9 NH 3)} x MoO 3 film of 50ppm of formaldehyde gas. 6 is a view showing a scanning electron micrograph of the surface of the LaAlO ₃ buffer layer shown in Example 5. FIG. Example 5 (a) LaAlO ₃ buffer layer, (b) MoO ₃ thin film, (c) [Na (H ₂ O) ₂ ] _x MoO ₃ thin film, and (d) (PPy) _x MoO ₃ thin film, It is a figure which shows the X-ray-diffraction pattern of. Is a diagram showing the sensor response to acetaldehyde gas 6ppm of Example 5 are shown _(PPy) x MoO ₃ thin film. Shown in Example 6, is a diagram showing _{(a) [Na (H 2} O) 2] x MoO 3 thin film, and _{(b) (C 4 H 9} NH 3) x MoO 3 film, the X-ray diffraction pattern . Shown in Example 7, a diagram illustrating the _{(a) [Na (H 2} O) 2] x MoO 3 thin film, and _{(b) (PANI) x MoO} 3 film, the X-ray diffraction pattern.

Claims (10)

  An organic-inorganic hybrid thin film comprising a silicon single crystal substrate and an organic-inorganic hybrid thin film formed on the substrate with a metal oxide buffer layer interposed therebetween.   2. The organic-inorganic hybrid thin film according to claim 1, wherein the organic-inorganic hybrid thin film is obtained by intercalating a hydrated alkali metal ion into a highly oriented thin film of an inorganic compound having a layered structure and further substituting the organic compound. .   The organic-inorganic hybrid thin film according to claim 1, wherein the organic-inorganic hybrid thin film is mainly composed of molybdenum oxide.   The organic-inorganic hybrid thin film according to claim 1 or 2, wherein the organic-inorganic hybrid thin film contains a conductive polymer.   The organic-inorganic hybrid thin film according to claim 1 or 2, wherein the organic-inorganic hybrid thin film contains organic ions.   The organic-inorganic hybrid thin film according to claim 1, wherein the buffer layer is a metal oxide having a lattice constant similar to that of molybdenum oxide.   In a method of manufacturing an organic-inorganic hybrid thin film obtained by forming an organic-inorganic hybrid thin film on a silicon single crystal substrate, the organic-inorganic hybrid thin film is grown on the silicon single crystal substrate with a buffer layer made of a metal oxide interposed. A method for producing an organic-inorganic hybrid thin film.   The organic-inorganic hybrid thin film according to claim 7, wherein a highly oriented thin film of an inorganic compound having a layered structure is intercalated with a hydrated alkali metal ion and further substituted with an organic compound to grow an organic-inorganic hybrid film. Production method.   A conductive member comprising the organic-inorganic hybrid thin film according to claim 1 as a constituent element. A chemical sensor member comprising the organic-inorganic hybrid thin film according to claim 1 as a sensor element.