CN-121992488-A - Preparation method of lanthanum aluminate/strontium titanate nanostructure for hydrogen detection

Abstract

The invention belongs to the field of film sensors, and discloses a preparation method of a lanthanum aluminate/strontium titanate nanostructure for hydrogen detection, which comprises the following steps: firstly preparing a strontium titanate single crystal substrate, depositing a single crystal epitaxial lanthanum aluminate film on the strontium titanate single crystal substrate by pulse laser to obtain a single crystal epitaxial lanthanum aluminate/strontium titanate material, then inducing the surface of the single crystal epitaxial lanthanum aluminate film by femtosecond laser to form a striped periodic surface nanostructure to obtain a lanthanum aluminate/strontium titanate nanostructure, and then depositing noble metal nanoparticles on the surface of the lanthanum aluminate/strontium titanate nanostructure. According to the invention, highly ordered monocrystal lanthanum aluminate/strontium titanate heterogeneous film is obtained by precisely controlling pulse laser deposition process parameters, and a nano stripe periodic structure is prepared on the surface of lanthanum aluminate by precisely controlling pulse femtosecond laser processing parameters, so that the specific surface area of the nano stripe periodic structure is effectively increased, gas adsorption sites are increased, and the two-dimensional electron gas-gas charge transmission capacity of the lanthanum aluminate/strontium titanate interface is improved.

Inventors

• ZHANG SHUOWEN
• YANG ZHENZHEN
• WU LING
• YANG CHONG
• SUN YANGJUN
• GAN XINGYU
• HUANG SHAOWEI
• FAN LISHA
• YAO JIANHUA

Assignees

• 德清县浙工大莫干山研究院

Dates

Publication Date

20260508

Application Date

20260409

Claims (9)

1. 1. A preparation method of a lanthanum aluminate/strontium titanate nanostructure for hydrogen detection is characterized by comprising the steps of preparing a strontium titanate monocrystal substrate, depositing a monocrystal epitaxial lanthanum aluminate film on the strontium titanate monocrystal substrate by pulse laser to obtain a monocrystal epitaxial lanthanum aluminate/strontium titanate material, inducing the surface of the monocrystal epitaxial lanthanum aluminate film to form a striped periodic surface nanostructure by using femtosecond laser to obtain the lanthanum aluminate/strontium titanate nanostructure, and depositing noble metal nanoparticles on the surface of the lanthanum aluminate/strontium titanate nanostructure.
2. 2. The method of claim 1, wherein the single crystal substrate of strontium titanate has a crystal orientation of (100) and the surface stop layer is titanium dioxide during the pulsed laser deposition.
3. 3. The method for preparing a lanthanum aluminate/strontium titanate nanostructure for hydrogen gas detection according to claim 1, wherein in the process of pulse laser deposition, the gas pressure in the cavity of the pulse laser deposition device is controlled to be 1 x 10 -7 Pa–1×10 -4 Pa, the oxygen partial pressure is controlled to be 1 x 10 -5 Pa–1×10 -2 Pa, the substrate temperature is 600-900 ℃, and a KrF excimer laser is used for pulse irradiation of the strontium titanate target.
4. 4. A method for preparing a lanthanum aluminate/strontium titanate nanostructure for hydrogen gas detection according to claim 3, wherein the laser energy density is controlled to be 0.5J/cm 2 –3J/cm 2 and the distance between the strontium titanate target and the strontium titanate single crystal substrate is controlled to be 5cm to 7cm in a high vacuum environment during the pulsed laser deposition process.
5. 5. A method for preparing a lanthanum aluminate/strontium titanate nanostructure for hydrogen gas detection according to claim 3, wherein the deposition thickness of the single crystal epitaxial lanthanum aluminate film is controlled to be 4nm-100nm during the pulsed laser deposition process.
6. 6. The method for preparing a lanthanum aluminate/strontium titanate nanostructure for hydrogen gas detection according to claim 1, wherein the linear polarized femtosecond laser irradiation is used to process the monocrystalline epitaxial lanthanum aluminate/strontium titanate material during the process of forming the striped periodic surface nanostructure on the surface of the monocrystalline epitaxial lanthanum aluminate film.
7. 7. The method for preparing a lanthanum aluminate/strontium titanate nanostructure for hydrogen gas detection according to claim 6, wherein the laser focusing diameter is controlled to be 10 μm-100 μm, the pulse width is controlled to be 10fs-800fs, the repetition frequency is controlled to be 10kHz-800kHz, the single pulse laser energy is in the range of 1 μj-20 μj, and the scanning speed is in the range of 0.100mm/s-100mm/s in the process of forming the striped periodic surface nanostructure on the surface of the single crystal epitaxial lanthanum aluminate film by femtosecond laser.
8. 8. The method for preparing a lanthanum aluminate/strontium titanate nanostructure for hydrogen gas detection according to claim 1, wherein in the process of depositing noble metal nanoparticles on the surface of the lanthanum aluminate/strontium titanate nanostructure, a magnetron sputtering method is used to deposit noble metal particles on the surface of the monocrystalline epitaxial lanthanum aluminate film.
9. 9. The method for preparing a lanthanum aluminate/strontium titanate nanostructure for hydrogen gas detection according to claim 8, wherein the sputtered particles are elemental metal particles or alloy particles with a particle diameter of 1nm-10nm in the process of depositing noble metal nanoparticles on the surface of the lanthanum aluminate/strontium titanate nanostructure.

Description

Preparation method of lanthanum aluminate/strontium titanate nanostructure for hydrogen detection Technical Field The invention relates to the field of film sensors, in particular to a preparation method of a lanthanum aluminate/strontium titanate nanostructure for hydrogen detection. Background The rapid development of nanotechnology promotes the progress of material surface engineering, and the accurate control of the micro-nano structure on the material surface has become one of the core technologies for optimizing the physical and chemical properties of the material. The lanthanum aluminate/strontium titanate (LaAlO 3/SrTiO3, abbreviated as LAO/STO) film heterostructure is focused on because the interface of the lanthanum aluminate/strontium titanate (LaAlO 3/SrTiO3) can form two-dimensional electron gas with high mobility, shows various singular quantum characteristics such as superconductivity, ferromagnetism and the like, and has wide application prospect in the fields of catalytic sensing and the like. However, the film crystallization quality of the traditional chemical liquid preparation method is lower and the interface quality is poor, while the molecular beam epitaxy method has higher precision, but the equipment is expensive, the operation is complex and the efficiency is low. In addition, the original LAO/STO film has strong surface chemical inertia, almost no response to target gas (such as hydrogen), and severely restricts the application of the LAO/STO film in the sensing field. In this regard, the catalytic activity of noble metal nanoparticles is usually utilized to enhance the performance of the gas sensor by loading the noble metal nanoparticles on the surface of the sensitive material, but the method has higher cost and weaker specific recognition of target gas. The invention designs a LAO/STO heterogeneous thin film nanostructure, which firstly uses a pulse laser deposition method to prepare a high-quality LAO/STO heterogeneous epitaxial thin film, and secondly uses a femtosecond laser processing technology to generate a periodic surface micro-nano structure on the surface of the thin film, wherein the periodic nano structure effectively enlarges the surface area, increases gas adsorption sites and is beneficial to enhancing gas sensing response. Based on this, a novel gas sensor capable of activating the LAO/STO hydrogen sensing function was developed. Disclosure of Invention The invention aims to provide a preparation method of a lanthanum aluminate/strontium titanate nanostructure for hydrogen detection, which aims to solve the problems in the prior art. In order to achieve the above purpose, the present invention provides the following technical solutions: a preparation method of a lanthanum aluminate/strontium titanate nanostructure for hydrogen detection is characterized by comprising the steps of preparing a strontium titanate monocrystal substrate, depositing a monocrystal epitaxial lanthanum aluminate film on the strontium titanate monocrystal substrate by pulse laser to obtain a monocrystal epitaxial lanthanum aluminate/strontium titanate material, inducing the surface of the monocrystal epitaxial lanthanum aluminate film to form a striped periodic surface nanostructure by using femtosecond laser to obtain the lanthanum aluminate/strontium titanate nanostructure, and depositing noble metal nanoparticles on the surface of the lanthanum aluminate/strontium titanate nanostructure. Further, in the pulse laser deposition process, the crystal orientation direction of the strontium titanate single crystal substrate is (100), and the surface stop layer is titanium dioxide. Further, in the pulse laser deposition process, the air pressure in the cavity of the pulse laser deposition equipment is controlled to be 1 multiplied by 10 -7Pa–1×10-4 Pa, the oxygen partial pressure is controlled to be 1 multiplied by 10 -5Pa–1×10-2 Pa, the substrate temperature is 600-900 ℃, and a KrF excimer laser is used for carrying out pulse irradiation on the strontium titanate target. Further, in the pulse laser deposition process, the laser energy density is controlled to be 0.5J/cm 2–3J/cm2 under a high vacuum environment, and the distance between the strontium titanate target material and the strontium titanate single crystal substrate is controlled to be 5cm-7cm. Further, in the pulse laser deposition process, the deposition thickness of the monocrystal epitaxial lanthanum aluminate film is controlled to be 4nm-100nm. Further, in the process of forming a striped periodic surface nanostructure on the surface of the monocrystalline epitaxial lanthanum aluminate film by femtosecond laser, linear polarized femtosecond laser irradiation is used for processing the monocrystalline epitaxial lanthanum aluminate/strontium titanate material. Further, in the process of forming the striped periodic surface nano structure on the surface of the monocrystal epitaxial lanthanum aluminate film by femtosecond laser,