Indium oxide nanorod, preparation method and application thereof in formaldehyde gas detection

Abstract

The application discloses a preparation method of indium oxide nanorods, which comprises the following steps: S1, placing indium oxide powder in a center temperature control position of a tube furnace, and then placing a washed silicon wafer at a downstream position away from the powder; S2, vacuumizing the inside of the tube furnace, and then continuously feeding argon; S3, adjusting a program to heat and maintain the temperature of the temperature control area of the tube furnace, and then naturally cooling the sample, so as to obtain the indium oxide nanorods grown on the surface of the silicon wafer. The preparation method can obtain the indium oxide nanorods, the size of the nanorods is very uniform, only a single indium oxide nanorod is needed to be sensitive to the formaldehyde gas, the response recovery time is only about 15 seconds, the indium oxide nanorod can obviously respond to the formaldehyde gas from 80 DEG C, and the application has a significant technical advantage compared with the prior art.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of toxic and harmful gas sensing and detecting, and particularly relates to an indium oxide nanorod, a preparation method thereof and application of the indium oxide nanorod in formaldehyde gas detection. BACKGROUND

[0002] As a typical one-dimensional nanomaterial, the nanorod has obvious size and structure advantages and can usually exhibit good electrical performance. Therefore, development of the nanorod material helps to solve the difficulties faced by photoelectric materials which cannot be applied due to size limitation and has good application value for manufacturing some small and micro electronic devices such as micro emitters, gas sensitive sensors and diodes.

[0003] Indium oxide is a semiconductor material, and its band gap is 2.9 eV. It has been proved that the indium oxide can exhibit good chemical stability under most conventional conditions and is also proved to be suitable for the field of gas detection. The formaldehyde gas which people often contact due to daily factors such as decoration and furniture has great harmfulness to human body and is more concerned among various toxic and harmful gases.

[0004] For a gas sensitive sensor, an important index is response recovery time. According to the article "Research Progress of Metal Oxide Semiconductor Sensor for Formaldehyde Field Rapid Detection" in the journal of Shandong Chemical, most of the current indium oxide formaldehyde gas sensors are counted, and it is known that the response recovery time of the current indium oxide formaldehyde gas sensor is generally greater than thirty or even forty seconds. On the other hand, as an important index of a gas sensitive material, the working temperature required for the material to realize gas sensitive response is usually about 150 DEG C for the indium oxide material, and there are problems of long response recovery time and high working temperature.

[0005] Therefore, a simple preparation method of the indium oxide nanorod is developed, and the nanorod material is sensitive to formaldehyde gas and has rapid response, which can provide good promotion for the development of the application of the formaldehyde gas detector. SUMMARY

[0006] In view of the deficiencies of the prior art, the application provides an indium oxide nanorod, a preparation method thereof and application of the indium oxide nanorod in formaldehyde gas detection. The preparation method of the indium oxide nanorod is simplified, and the obtained indium oxide nanorod has good sensitivity to formaldehyde gas.

[0007] In order to achieve the above purpose, the technical scheme adopted by the application is as follows:

[0008] A preparation method of an indium oxide nanorod, comprising the following steps:

[0009] S1: Put indium oxide powder in the center temperature control position of a tube furnace, and then put a cleaned silicon wafer in a position 10-15 cm downstream from the powder;

[0010] S2: Vacuumize the inside of the tube furnace, and then continuously introduce argon gas;

[0011] S3: Adjust the program to heat and maintain the temperature of the temperature control area of the tube furnace, and then naturally cool the sample to obtain indium oxide nanorods grown on the surface of the silicon wafer.

[0012] Further, the content of the indium oxide powder in step S1 is 99.99%.

[0013] Further, in step S1, the cleaned silicon wafer is placed in a position 10-15 cm downstream from the powder.

[0014] Further, in step S2, the inside of the tube furnace is vacuumized to 20-50 Pa.

[0015] Further, the flow rate of the argon gas in step S2 is 25-30 sccm.

[0016] Further, the purity of the argon gas is 99.9%.

[0017] Further, in step S3, the program is adjusted to heat the temperature control area of the tube furnace to 1050-1100℃ and maintain for 110-120 min.

[0018] The application also provides an application of the indium oxide nanorod in formaldehyde gas detection, comprising the following steps:

[0019] (1) Scrape the indium oxide nanorod into ethanol, and drop the obtained suspension onto a new silicon wafer;

[0020] (2) Use a tungsten wire to uniformly wrap the surface of the silicon wafer obtained in step S4, deposit a metal thin film on the surface of the silicon wafer with the tungsten wire-wrapped indium oxide nanorod, and after removing the tungsten wire, an indium oxide nanorod formaldehyde gas sensor is obtained, which is used for formaldehyde gas detection.

[0021] Further, in step (2), the diameter of the tungsten wire is 15-20 μm, the thickness of the metal thin film is 50-60 nm, and the metal includes one of titanium, gold and copper.

[0022] The application has the following beneficial effects:

[0023] (1) The required equipment and raw materials of the application are not expensive, and the preparation process is simple.

[0024] (2) The preparation method of the present application can obtain indium oxide nanorods, the size of which is very uniform, and only a single indium oxide nanorod is sensitive to formaldehyde gas, the response recovery time of which is only about 15 seconds, and it can produce obvious response to formaldehyde gas from 80℃, and reaches the best state at 160℃.

[0025] (3) The response recovery time of the current indium oxide formaldehyde gas sensor is generally more than thirty or even forty seconds. On the other hand, as an important indicator of gas sensitive material, the working temperature required for the material to achieve gas sensitive response is usually about 150℃ for indium oxide material. The indium oxide nanorod prepared by the present application can reduce the response recovery time to about 15 seconds, and has good gas sensitive response intensity at a working temperature of 80-160℃, which has a significant technical advantage. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 It is a transmission electron micrograph of the indium oxide nanorod of the present application.

[0027] Figure 2 It is a photo of a single indium oxide nanorod formaldehyde gas sensor.

[0028] Figure 3 It is a gas sensitivity graph of an indium oxide nanorod formaldehyde gas sensor.

[0029] Figure 4 It is a temperature performance curve graph of a single indium oxide nanorod formaldehyde gas sensor. DETAILED DESCRIPTION

[0030] The technical solutions in the embodiments of the present application will be described clearly and completely below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0031] Embodiment 1

[0032] A preparation method of an indium oxide nanorod formaldehyde gas sensor, comprising the following steps:

[0033] S1: Place the indium oxide powder with a content of 99.99% at the center temperature control position of the tube furnace, and then place a piece of washed silicon wafer at a distance of 15 cm from the powder;

[0034] S2: Vacuumize the inside of the tube furnace to 30 Pa, and then continuously introduce argon gas with a purity of 99.9% at a flow rate of 30 sccm;

[0035] S3: adjust the program to make the temperature of the tube furnace control area to 1100℃, and maintain 120 min, then let the sample cool naturally, to get the indium oxide nanorods grown on the surface of the silicon wafer (see the transmission electron microscopy image Figure 1 );

[0036] S4: scrape the uniform size of indium oxide nanorods on the silicon wafer into ethanol, drop the obtained suspension onto a new silicon wafer;

[0037] S5: use a tungsten wire with a diameter of 15 μm to uniformly wrap the surface of the silicon wafer obtained in step S4, deposit a 60 nm metal film on the surface of the silicon wafer with the tungsten wire-wrapped indium oxide nanorods, and then remove the tungsten wire to obtain a single indium oxide nanorod formaldehyde gas sensor (see Figure 2 ).

[0038] Connect the single indium oxide nanorod formaldehyde gas sensor device prepared in this example to a current detection system and place the device in a gas environment containing 20 ppm concentration of formaldehyde, it can be known that only a single indium oxide nanorod can produce obvious current intensity change to formaldehyde gas (see Figure 3 ), and the response recovery time is 15 seconds. By controlling the temperature of the sensor through a heating stage, see Figure 4 , it is found that the sensor exhibits a response amplitude of 1.96 times to 20 ppm concentration of formaldehyde gas at 160℃, and even at 80℃, the sensor still exhibits a gas sensitive response intensity of 1.72 times, having a large temperature detection range.

[0039] Example 2

[0040] A preparation method of an indium oxide nanorod formaldehyde gas sensor, comprising the following steps:

[0041] S1: place the indium oxide powder with a content of 99.99% at the center temperature control position of the tube furnace, then place a washed silicon wafer at a distance of 10 cm from the powder;

[0042] S2: vacuumize the inside of the tube furnace to 22 Pa, then continuously pass in argon gas with a purity of 99.9% at a flow rate of 25 sccm;

[0043] S3: adjust the program to make the temperature of the tube furnace control area to 1100℃, and maintain 120 min, then let the sample cool naturally, to get the indium oxide nanorods grown on the surface of the silicon wafer;

[0044] S4: scrape the uniform size of indium oxide nanorods on the silicon wafer into ethanol, drop the obtained suspension onto a new silicon wafer;

[0045] S5: using a tungsten wire with a diameter of 15 μm to uniformly wind the surface of the silicon wafer obtained in step S4, depositing a 51 nm metal film on the surface of the silicon wafer with the indium oxide nanorods wound with the tungsten wire, and obtaining a single indium oxide nanorod formaldehyde gas sensor after removing the tungsten wire.

[0046] Example 3

[0047] A method for preparing an indium oxide nanorod formaldehyde gas sensor, comprising the following steps:

[0048] S1: placing indium oxide powder with a content of 99.99% at a center temperature control position of a tube furnace, and then placing a washed silicon wafer at a distance of 12 cm from the powder;

[0049] S2: vacuumizing the inside of the tube furnace to 25 Pa, and then continuously introducing 99.9% pure argon at a flow rate of 25 sccm;

[0050] S3: adjusting the program to raise the temperature control area of the tube furnace to 1100°C and maintain for 120 min, and then naturally cooling the sample, to obtain indium oxide nanorods grown on the surface of the silicon wafer;

[0051] S4: scraping the uniformly sized indium oxide nanorods on the silicon wafer into ethanol, and dropping the obtained suspension onto a new silicon wafer;

[0052] S5: using a tungsten wire with a diameter of 16 μm to uniformly wind the surface of the silicon wafer obtained in step S4, depositing a 53 nm metal film on the surface of the silicon wafer with the indium oxide nanorods wound with the tungsten wire, and obtaining a single indium oxide nanorod formaldehyde gas sensor after removing the tungsten wire.

[0053] Example 4

[0054] A method for preparing an indium oxide nanorod formaldehyde gas sensor, comprising the following steps:

[0055] S1: placing indium oxide powder with a content of 99.99% at a center temperature control position of a tube furnace, and then placing a washed silicon wafer at a distance of 13 cm from the powder;

[0056] S2: vacuumizing the inside of the tube furnace to 28 Pa, and then continuously introducing 99.9% pure argon at a flow rate of 26 sccm;

[0057] S3: adjusting the program to raise the temperature control area of the tube furnace to 1100°C and maintain for 120 min, and then naturally cooling the sample, to obtain indium oxide nanorods grown on the surface of the silicon wafer;

[0058] S4: scraping the uniformly sized indium oxide nanorods on the silicon wafer into ethanol, and dropping the obtained suspension onto a new silicon wafer;

[0059] S5: using a tungsten wire with a diameter of 17 μm to uniformly wind the surface of the silicon wafer obtained in step S4, depositing a 54 nm metal film on the surface of the silicon wafer with the indium oxide nanorods wound with the tungsten wire, and obtaining a single indium oxide nanorod formaldehyde gas sensor after removing the tungsten wire.

[0060] Example 5

[0061] A method for preparing an indium oxide nanorod formaldehyde gas sensor, comprising the following steps:

[0062] S1: placing indium oxide powder with a content of 99.99% at a center temperature control position of a tube furnace, and then placing a washed silicon wafer at a distance of 12 cm from the powder;

[0063] S2: vacuumizing the inside of the tube furnace to 40 Pa, and then continuously introducing 99.9% pure argon at a flow rate of 27 sccm;

[0064] S3: adjusting the program to heat the temperature control area of the tube furnace to 1100°C and maintaining for 120 min, and then naturally cooling the sample, to obtain indium oxide nanorods grown on the surface of the silicon wafer;

[0065] S4: scraping the uniformly sized indium oxide nanorods on the silicon wafer into ethanol, and dropping the obtained suspension onto a new silicon wafer;

[0066] S5: using a tungsten wire with a diameter of 20 μm to uniformly wind the surface of the silicon wafer obtained in step S4, depositing a 58 nm metal film on the surface of the silicon wafer with the indium oxide nanorods wound with the tungsten wire, and obtaining a single indium oxide nanorod formaldehyde gas sensor after removing the tungsten wire.

[0067] Example 6

[0068] A method for preparing an indium oxide nanorod formaldehyde gas sensor, comprising the following steps:

[0069] S1: placing indium oxide powder with a content of 99.99% at a center temperature control position of a tube furnace, and then placing a washed silicon wafer at a distance of 15 cm from the powder;

[0070] S2: vacuumizing the inside of the tube furnace to 29 Pa, and then continuously introducing 99.9% pure argon at a flow rate of 30 sccm;

[0071] S3: adjusting the program to heat the temperature control area of the tube furnace to 1100°C and maintaining for 120 min, and then naturally cooling the sample, to obtain indium oxide nanorods grown on the surface of the silicon wafer;

[0072] S4: scraping the uniformly sized indium oxide nanorods on the silicon wafer into ethanol, and dropping the obtained suspension onto a new silicon wafer;

[0073] S5: using a tungsten wire with a diameter of 16 μm to uniformly wind the surface of the silicon wafer obtained in step S4, depositing a 60 nm metal film on the surface of the silicon wafer with the indium oxide nanorods wound with the tungsten wire, and obtaining a single indium oxide nanorod formaldehyde gas sensor after removing the tungsten wire.

[0074] Example 7

[0075] A method for preparing an indium oxide nanorod formaldehyde gas sensor, comprising the following steps:

[0076] S1: placing indium oxide powder with a content of 99.99% at a center temperature control position of a tube furnace, and then placing a washed silicon wafer at a distance of 12 cm from the powder;

[0077] S2: vacuumizing the inside of the tube furnace to 35 Pa, and then continuously introducing 99.9% pure argon at a flow rate of 30 sccm;

[0078] S3: adjusting the program to heat the temperature control area of the tube furnace to 1100°C and maintaining for 120 min, and then naturally cooling the sample, to obtain indium oxide nanorods grown on the surface of the silicon wafer;

[0079] S4: scraping the uniformly sized indium oxide nanorods on the silicon wafer into ethanol, and dropping the obtained suspension onto a new silicon wafer;

[0080] S5: using a tungsten wire with a diameter of 18 μm to uniformly wind the surface of the silicon wafer obtained in step S4, depositing a 56 nm metal film on the surface of the silicon wafer with the indium oxide nanorods wound with the tungsten wire, and obtaining a single indium oxide nanorod formaldehyde gas sensor after removing the tungsten wire.

[0081] Example 8

[0082] A method for preparing an indium oxide nanorod formaldehyde gas sensor, comprising the following steps:

[0083] S1: placing indium oxide powder with a content of 99.99% at a center temperature control position of a tube furnace, and then placing a washed silicon wafer at a distance of 15 cm from the powder;

[0084] S2: vacuumizing the inside of the tube furnace to 45 Pa, and then continuously introducing 99.9% pure argon at a flow rate of 28 sccm;

[0085] S3: adjusting the program to heat the temperature control area of the tube furnace to 1100°C and maintaining for 120 min, and then naturally cooling the sample, to obtain indium oxide nanorods grown on the surface of the silicon wafer;

[0086] S4: scraping the uniformly sized indium oxide nanorods on the silicon wafer into ethanol, and dropping the obtained suspension onto a new silicon wafer;

[0087] S5: using tungsten wire with diameter of 16 μm to uniformly wind the surface of the silicon wafer obtained in step S4, depositing 55 nm metal film on the surface of the silicon wafer with the indium oxide nanorod attached and the tungsten wire removed to obtain a single indium oxide nanorod formaldehyde gas sensor.

[0088] Although the specific embodiments of the present application are described in detail with reference to the embodiments, it should not be understood as limiting the scope of protection of the patent. Various modifications and variations of the present application, which can be made by those skilled in the art without creative effort, are still within the scope of protection of the patent described in the claims.

Claims

1. A method for preparing indium oxide nanorods, characterized by, The method comprises the following steps: S1: placing indium oxide powder in the center temperature control position of a tube furnace, and then placing a cleaned silicon wafer at a position 10-15 cm downstream from the powder; S2: vacuumizing the inside of the tube furnace, and then continuously supplying argon; S3: adjusting the program to heat and maintain the temperature of the temperature control area of the tube furnace, and then naturally cooling the sample to obtain indium oxide nanorods grown on the surface of the silicon wafer; In step S1, the cleaned silicon wafer is placed at a position 10-15 cm downstream from the powder; In step S2, the inside of the tube furnace is vacuumized to 20-50 Pa; In step S2, the flow rate of the argon is 25-30 sccm; In step S3, the program is adjusted to heat the temperature control area of the tube furnace to 1050-1100℃, and maintain the temperature for 110-120 min.

2. The method for preparing indium oxide nanorods according to claim 1, characterized in that, In step S1, the content of the indium oxide powder is 99.99%.

3. The method for preparing indium oxide nanorods according to claim 1, characterized in that, The purity of the argon is 99.9%.

4. Indium oxide nanorods prepared by the method according to any one of claims 1-3.

5. Use of the indium oxide nanorods according to claim 4 for the detection of formaldehyde gas, characterized in that, The method comprises the following steps: (1) scraping the indium oxide nanorods into ethanol, and dropping the obtained suspension onto a new silicon wafer; (2) uniformly winding the surface of the silicon wafer obtained in step S4 with a tungsten wire, depositing a metal thin film on the surface of the silicon wafer with the tungsten wire and the attached indium oxide nanorods, and obtaining an indium oxide nanorod formaldehyde gas sensor after removing the tungsten wire, which is used for formaldehyde gas detection. 6.The application of indium oxide nanorods in formaldehyde gas detection according to claim 5, characterized in that, In step (2), the diameter of the tungsten wire is 15-20 μm, the thickness of the metal thin film is 50-60 nm, and the metal comprises one of titanium, gold and copper.

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