CN111496384B - A processing device and method for nanopore array on the surface of brittle material - Google Patents

Abstract

The present invention provides a processing device and method for nanopore array on the surface of brittle material, wherein the upper surface of the brittle material substrate is coated with a metal film, a single layer of densely arranged microspheres is laid on the metal film, and the brittle material substrate is placed on a workbench; a laser, a beam expander, and a beam shaper are arranged in sequence in the horizontal direction, and a scanning galvanometer and a focusing lens set workbench are arranged in sequence from top to bottom in the vertical direction; the laser generated by the laser passes through the beam expander and the beam shaper in sequence, and then is reflected by a reflector to reach the scanning galvanometer and the focusing lens, and then irradiates the upper surface of the brittle material substrate coated with the metal film and paved with microspheres; a computer is connected to the laser set scanning galvanometer, and the computer controls the pulse energy and repetition frequency of the laser beam generated by the laser. The application of this technical solution to lay a single layer of densely arranged microspheres on the surface of the brittle material substrate can realize the processing of a large-area nanopore array.

Description

A processing device and method for nanopore array on the surface of brittle material

Technical Field

The invention relates to the technical field of laser processing, and in particular to a processing device and method for a nano-hole array on the surface of a brittle material.

Background Art

Nanopore arrays have a wide range of applications in solar cells, light-emitting devices, electrochemical energy storage, nanophotonics, sensors, etc. due to their excellent physical and chemical properties, optoelectronic properties, surface effects, quantum confinement effects, thermal stability and other special physical properties. Focused ion beam etching and electron beam etching can prepare nanopore arrays on the surface of brittle materials, but the high cost and complex preparation process limit their wide application.

Summary of the invention

The purpose of the present invention is to provide a device and method for processing nanopore arrays on the surface of brittle materials. By laying a single layer of densely arranged microspheres on the surface of a brittle material substrate, large-area nanopore array processing can be achieved.

In order to solve the above technical problems, the present invention provides a processing device for nanopore array on the surface of a brittle material, wherein the upper surface of a brittle material substrate is coated with a metal film, a single layer of densely arranged microspheres is laid on the metal film, and the brittle material substrate is placed on a workbench;

The laser, beam expander, and beam shaper are arranged in sequence along the horizontal direction, and the scanning galvanometer, focusing lens, and workbench are arranged in sequence from top to bottom along the vertical direction;

The laser generated by the laser passes through a beam expander and a beam shaper in sequence, and then is reflected by a reflector to reach a scanning galvanometer and a focusing lens, and then irradiates the upper surface of a brittle material substrate coated with a metal film and covered with microspheres; a computer is connected to the laser set scanning galvanometer, and the computer controls the pulse energy and repetition frequency of the laser beam generated by the laser.

In a preferred embodiment, the beam shaper converts a laser beam with Gaussian energy distribution into a laser beam with uniform energy distribution.

In a preferred embodiment, the computer controls the movement of the scanning galvanometer to control the moving trajectory and scanning speed of the laser beam acting on the brittle material substrate in the xy plane.

In a preferred embodiment, the brittle material substrate is a non-metallic material, specifically one of glass, sapphire, silicon carbide, silicon, gallium arsenide, gallium nitride, diamond, ceramic and laser crystal material.

In a preferred embodiment, the material of the metal film is gold, silver, copper, aluminum, platinum, titanium or an alloy thereof, and the thickness of the metal film is between 10 nanometers and 200 nanometers.

In a preferred embodiment, the metal film is composed of a layer of the same metal material or a layer of metal alloy material or multiple layers of different metal materials.

The present invention also provides a method for processing a nanopore array on the surface of a brittle material, which adopts the processing device for the nanopore array on the surface of a brittle material, wherein the laser generated by the laser is sequentially irradiated to the upper surface of a brittle material substrate coated with a metal film and provided with microspheres through a beam expander, a beam shaper, a reflector, a scanning galvanometer and a focusing lens; a computer controls the laser and the scanning galvanometer to write the nanopore array on the upper surface of the brittle material substrate; the remaining microspheres and the metal film on the surface of the brittle material substrate processed with the nanopore array are removed; and after ultrasonic cleaning, a brittle material substrate with a nanopore array is obtained.

Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

The present invention provides a processing device and method for nanopore arrays on the surface of brittle materials, which replaces the method of directly preparing nanopore arrays by laying microspheres on the surface of brittle materials. Microspheres are used to focus the laser beam to the nanometer scale and directly prepare nanopore arrays on the surface of brittle materials. There are a large number of ablation sputterings around the nanopores processed by this method, and the geometric shape accuracy of the nanopores is poor. The present invention can not only reduce the sputterings around the nanopores, but also improve the geometric shape accuracy of the ablated nanopores by coating a metal film on the surface of the brittle material substrate and laying a single layer of densely arranged microspheres on the surface of the metal film.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic structural diagram of a device for processing nanopore arrays on the surface of brittle materials in a preferred embodiment of the present invention;

Figure 2 is a scanning electron microscope image of a nanohole array prepared by picosecond laser on (a) a silicon substrate without gold film and (b) a silicon substrate coated with 10 nm thick gold film in a preferred embodiment of the present invention. The corresponding laser processing parameters are: laser center wavelength 1064nm, pulse width 12ps, laser energy density 1.58J/ ^cm2 , scanning speed 6000mm/s;

Figure 3 is an atomic force microscope image of a nanohole array prepared by picosecond laser on (a) a silicon substrate without gold film and (b) a silicon substrate coated with 10 nm thick gold film in a preferred embodiment of the present invention. The corresponding laser processing parameters are: laser center wavelength 1064nm, pulse width 12ps, laser energy density 1.58J/ ^cm2 , scanning speed 6000mm/s;

FIG4 is a cross-sectional (xz plane) geometry of the nanopore at the marked positions in FIG3 (a) and (b) in a preferred embodiment of the present invention;

FIG. 5 is a graph showing the ablation depth size distribution of all nanopores in FIG. 3 (a) and (b) in a preferred embodiment of the present invention.

DETAILED DESCRIPTION

The present invention is further described below in conjunction with the accompanying drawings and specific embodiments.

The present invention provides a processing device and method for nanohole arrays on the surface of brittle materials, which replaces the method of using microspheres to focus the laser beam to the nanometer scale and then directly preparing the nanohole array on the surface of the brittle material, and solves the problems of a large amount of ablation sputtering around the nanoholes and low geometric shape accuracy of the nanoholes. The physical mechanism includes: first, there are a large number of free electrons in the metal film, and these free electrons will quickly diffuse to the metal film-brittle material substrate interface after absorbing the energy of the incident photon, resulting in the free electron density on the surface of the brittle material coated with the metal film under laser irradiation being much higher than the free electron density on the surface of the brittle material without the film. The high-density free electrons on the metal film-brittle material substrate interface can enhance the energy transfer between the incident laser and the brittle material, thereby improving the absorption of the laser energy by the brittle material, and the brittle material is mainly removed in the form of vaporization, so there are fewer ablation sputtering around the nanoholes. In addition, the high-density free electrons provided by the metal film are conducive to the uniform deposition of laser energy on the surface of the brittle material, which makes the brittle material absorb the laser energy more uniformly, thereby improving the geometric shape accuracy of the ablation hole.

As shown in FIG1 , the processing device for the nanopore array on the surface of a brittle material of the present invention comprises: a laser (1), a beam expander (2), a beam shaper (3), a reflector (4), a scanning galvanometer (5), a focusing lens (6), a workbench (8) and a computer (9).

In order to make the purpose, technical solution and advantages of the embodiment of the present invention clearer, the following describes a method and device for processing a nanopore array using the above-mentioned brittle material. In this embodiment, the laser is a picosecond laser with a wavelength of 1064nm, a pulse width of 12ps, and a repetition frequency adjustable from 20 to 500kHz; the material of the microsphere (71) is polystyrene, and the diameter of the microsphere (71) is close to the wavelength of the incident light. In this embodiment, the diameter of the microsphere (71) is 1μm; the processed brittle material is a silicon substrate with a size of 10mm×10mm and a thickness of 0.5mm, which specifically includes the following steps:

Step 1: A 10 nm thick gold film is plated on the surface of a flaky silicon substrate, i.e., a brittle material substrate (73), using magnetron sputtering technology. Metal films (72) of different thicknesses or other types of metal films (72) may also be plated. This does not limit the scope of protection of the present invention.

Step 2: Lay a single layer of densely arranged polystyrene microspheres (71) with a diameter of 1 μm on the surface coated with the metal film (72), and place the sample on a workbench. Microspheres (71) of different diameters or microspheres (71) of other materials can also be laid, and this does not limit the scope of protection of the present invention.

Step 3: The laser light emitted by the picosecond laser (1) is sequentially irradiated onto the surface of the brittle material substrate (73) coated with a metal film (72) of the microsphere (71) through a beam expander (2), a beam shaper (3), a reflector (4), a scanning galvanometer (5) and a focusing lens (6).

Step 4: The computer (9) controls the picosecond laser (1) and the scanning galvanometer (4) to adjust the laser energy density, repetition frequency, and scanning speed irradiated on the upper surface of the brittle material substrate (73) coated with the metal film (72) of the microsphere (71). In this embodiment, the laser energy density is set to 1.58 J/ ^cm2 , the repetition frequency is 100 kHz, and the scanning speed is 6000 mm/s. Other laser parameters can also be used, and the protection scope of the present invention is not limited by this.

Step 5: removing the remaining microspheres (71) and metal film (72) on the surface of the brittle material substrate (73) processed with the nanopore array.

Step 6: The brittle material substrate (73) with the microspheres (71) and the metal film (72) removed is ultrasonically cleaned with acetone, alcohol, and deionized water, respectively, and finally dried with nitrogen to obtain a silicon substrate with a nanopore array.

Figure 2 (a) and (b) are scanning electron microscope images of nanopore arrays on silicon substrates without and with metal films, respectively. By comparison, it is found that after a metal film is coated on the silicon surface, the ablation sputtering around the nanopores is significantly reduced; Figure 3 (a) and (b) are atomic force microscope images of nanopore arrays on silicon substrates without and with metal films, respectively. Figure 4 (a) and (b) are the cross-sectional geometric shapes of the nanopores at the marked positions in the uncoated and coated images of Figure 3 (a). By comparison, it is found that the geometric shape accuracy of the nanopores on the silicon substrate coated with metal films is higher; therefore, metal films can improve the geometric shape accuracy of nanopores. Comparing the depth size distribution of nanopores coated with and without metal films under the same laser parameters, as shown in Figure 5, it is found that after a metal film is coated on the silicon surface, the ablation depth of the nanopores is significantly greater than the ablation depth of the uncoated nanopores, indicating that metal films can improve the hole depth of laser-processed nanopores.

The present invention discloses a processing method and device for nanopore arrays on the surface of brittle materials. Experimental results show that after a metal film is plated on the surface of a brittle material substrate, there are fewer ablation sputterings around the nanopores, the geometric shape accuracy of the nanopores is higher, and the ablation depth of the nanopores is significantly increased. This method has important guiding significance for efficiently preparing high-quality and high-precision nanopore arrays on the surface of brittle materials.

The above is only a preferred specific implementation of the present invention, but the design concept of the present invention is not limited to this. Any technician familiar with the technical field who uses this concept to make non-substantial changes to the present invention within the technical scope disclosed by the present invention shall be deemed to infringe the protection scope of the present invention.

Claims (5)

1. The processing device of the nano-pore array on the surface of the brittle material is characterized in that a metal film is plated on the upper surface of a brittle material substrate, single-layer densely arranged microspheres are paved on the metal film, and the brittle material substrate is placed on a workbench; the laser, the beam expander and the beam shaper are sequentially arranged along the horizontal direction, and the scanning galvanometer and the condensing lens set workbench are sequentially arranged along the vertical direction from top to bottom; the laser generated by the laser sequentially passes through the beam expander and the beam shaper, then is reflected by the reflector to reach the scanning galvanometer and the focusing lens, and is irradiated to the upper surface of the brittle material substrate coated with the metal film and paved with the microspheres; the computer is connected with the laser and the scanning galvanometer, and controls the pulse energy and the repetition frequency of the laser beam generated by the laser;

The beam shaper converts a laser beam with energy in Gaussian distribution into a laser beam with energy in uniform distribution;

The computer controls the motion of the scanning galvanometer to control the trajectory and scanning speed of the laser beam acting on the brittle material substrate in the xy plane.

2. The apparatus for processing a nanopore array on a surface of a brittle material according to claim 1, wherein the brittle material substrate is a nonmetallic material, specifically one of glass, sapphire, silicon carbide, silicon, gallium arsenide, gallium nitride, diamond, ceramic, and a laser crystal material.

3. The device for processing the nanopore array on the surface of the brittle material according to claim 1, wherein the material of the metal film is one of gold, silver, copper, aluminum, platinum, titanium or an alloy thereof, and the thickness of the metal film is between 10 nm and 200 nm.

4. A device for processing a nanopore array on a surface of a brittle material according to claim 3, wherein the metal film is composed of a layer of the same metal material or a layer of a metal alloy material or a plurality of layers of different metal materials.

5. The processing method of the nano-pore array on the surface of the brittle material is characterized in that the processing device of the nano-pore array on the surface of the brittle material, which is disclosed in any one of claims 1 to 4, is adopted, and laser generated by a laser is irradiated to the upper surface of the brittle material substrate coated with the metal film and paved with microspheres through a beam expander, a beam shaper, a reflecting mirror, a scanning galvanometer and a focusing lens in sequence; the computer controls the laser and the scanning galvanometer to write the nanopore array on the upper surface of the brittle material substrate; removing the residual microspheres and metal films on the surface of the brittle material substrate with the nano-pore array; and after ultrasonic cleaning, obtaining the brittle material substrate with the nanopore array.