NO2 sensor and preparation method thereof

A technology of sensors and epitaxial thin films, which is applied in the field of NO2 sensors based on WO3 epitaxial thin films and its preparation, can solve the problems of reduced sensitivity, low barriers to mass production repeatability, long response time, etc., to achieve improved detection capabilities and stability, micro Compatibility with processing technology and the effect of improving detection efficiency

CN106124575AActive Publication Date: 2016-11-16SUZHOU UNIV OF SCI & TECH
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Publication Date
2016-11-16

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Abstract

The invention discloses an NO2 sensor and a preparation method thereof. The sensor comprises an oxide single crystal substrate, a WO3 epitaxial thin film, test electrodes and noble metal catalysts. The concentration of the NO2 gas in the environment is calibrated by measuring change of the resistance value of the WO3 epitaxial thin film between the test electrodes. Distortion and tilting of a structural motif WO6 octahedron of the WO3 epitaxial thin film are achieved by regulating the stress on the interface of the oxide single crystal substrate and the WO3 epitaxial thin film to obtain the WO3 epitaxial thin film with specific crystalline phase and exposed crystal plane, higher surface activity and reaction site concentrations and stable properties, thereby improving the detectivity and stability of the NO2 sensor. The sensor provided by the invention can be used for detecting NO2 with concentration of 40mu g / m<3>-20mg / m<3>, has short response time and stable properties, can be used for monitoring the concentration of NO2 in the atmospheric environment in real time and has a broad application prospect.
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Description

technical field

[0001] The invention belongs to the technical field of metal oxide-based resistance type gas sensing, and specifically relates to a WO-based 3 NO of epitaxial film 2 Sensors and methods of making them. Background technique

[0002] With the rapid economic development, nitrogen dioxide (NO2) emitted from automobiles and factories 2 ) has become one of the main air pollutants, seriously threatening human health. World Health Organization research shows that people with lower immunity 2 The concentration is 20~200μg / m 3 If you live in the environment for 1 to 8 hours, symptoms such as decreased lung function and airway inflammation will appear. when NO 2 The concentration is 41.7mg / m 3 , even short-term exposure can be life-threatening. Therefore, both China and WHO will NO 2 The 1-hour concentration limit and the annual average concentration limit are set at 200 μg / m 3 and 40μg / m 3 .

[0003] Currently widely used NO 2 Detection techniques include ...

Examples

Embodiment 1

[0027] See attached figure 1 , which is the NO provided by this example 2 Schematic diagram of the sensor structure with SrTiO 3 (001) is a single crystal substrate, and the sensor adopts the laser molecular beam epitaxy (Laser-MBE) method to grow WO on the oxide single crystal substrate 1 3 Epitaxial film 2, and then prepare test electrode 3, and in WO 3 Precious metal catalyst particles 4 are deposited on the surface of the epitaxial film to produce NO 2 sensor. The specific production process is as follows:

[0028] (1) Cleaning SrTiO 3 (001) single crystal substrate. SrTiO 3 (001) The single crystal substrate was ultrasonically cleaned in acetone solution for 5 minutes, rinsed with deionized water and corroded in HF solution for 5 minutes, then rinsed with deionized water and dried to obtain a clean single crystal substrate.

[0029] (2) Growing WO 3 epitaxial film. SrTiO 3 The (001) single crystal substrate is placed in a laser molecular beam epitaxy device an...

Embodiment 2

[0036] The materials and process steps used in this example are basically the same as in Example 1, only the WO in step (2) 3 The growth rate of the epitaxial film was adjusted to 10 nm / s.

[0037] XRD and RHEED test results show that the deposited WO 3 The film is an epitaxial film with good crystalline quality, and its effect on NO 2 The test result is comparable with embodiment 1.

Embodiment 3

[0039] NO provided by this example 2 Sensor, the preparation steps are as follows:

[0040] (1) Cleaning SrTiO 3 (001) single crystal substrate. SrTiO 3 (001) The single crystal substrate was ultrasonically cleaned in acetone solution for 5 minutes, rinsed with deionized water and corroded in HF solution for 5 minutes, then rinsed with deionized water and dried to obtain a clean single crystal substrate.

[0041] (2) Growing WO 3 epitaxial film. SrTiO 3 The (001) single crystal substrate is placed in a laser molecular beam epitaxy device and heated to 600°C. Bombardment of WO with 1Hz, 350mW pulsed KrF laser 3 solid target surface, enabling WO 3 Material evaporates instantly and deposits onto SrTiO 3 (001) single crystal substrate surface to obtain WO 3 For epitaxial thin films, the growth rate is about 0.01nm / s.

[0042] (3) Sputtering deposition method in WO 3 Fabrication of Pt particles on the surface of epitaxial thin film as NO 2 detected catalyst.

[0043]...