CN1346895A - Process for preparing high-melting-point photon crystal material - Google Patents

Abstract

The invention belongs to the field of inorganic optical materials, and in particular relates to a method for preparing photonic crystal materials with high melting points such as various metals, alloys and semiconductors. Using three-dimensional ordered polystyrene balls as a template, various materials are infiltrated into the gaps of polystyrene balls by means of electrochemical plating, ion sputtering and pulsed laser sputtering, respectively. Highly ordered, large aperture, high specific surface pure metals, alloys, semiconductors and other high melting point photonic crystal materials. The pore size of the resulting material can be varied by adjusting the diameter of the polystyrene pellets. The prepared photonic crystal material with high melting point is widely used in optical devices.

Description

A kind of preparation method of high melting point photonic crystal material

technical field

The invention belongs to the field of inorganic porous materials, in particular to a method for preparing metal, alloy and semiconductor photonic crystal materials with high melting point.

technical background

At present, the main methods for synthesizing photonic crystals are: stacking polystyrene beads or silica beads with uniform diameters into a three-dimensional ordered structure, and then: 1) stacking polystyrene beads or silica beads in three-dimensional order The sols of different materials (such as silica sol, titanium dioxide sol, etc.) are infiltrated into the gaps of the spheres. After the sol is solidified, the polystyrene spheres are removed by roasting or the silica spheres are removed by dissolution to obtain a three-dimensional ordered pore structure. 2) Infiltrate the solution containing nanoparticles into the gaps of three-dimensional ordered polystyrene beads or silica beads. After the solvent volatilizes, the nanoparticles accumulate in the gaps. Three-dimensionally ordered porous materials. However, the structure of the materials obtained by these methods is unstable, and these methods require the sol or nanoparticles of the required materials to be obtained first, and these two are not easy to obtain for most materials, especially metals, alloys, and semiconductor materials, thus limiting the use of These methods are widely applied to metals, alloys, and semiconductor materials that have important development prospects in the field of photonic crystals. Therefore, it is more urgent to propose a new method to prepare high-melting photonic crystal materials such as pure metals, alloys, and semiconductors with high order, large aperture, and high specific surface area.

Contents of the invention

The purpose of the present invention is to propose a preparation method of high melting point photonic crystal materials such as pure metals, alloys and semiconductors with high order degree, large aperture and high specific surface area.

The method for preparing high-melting-point photonic crystal materials such as metals, alloys, and semiconductors proposed by the present invention uses polystyrene beads arranged in three-dimensional order as a template, and uses a coating process to fill metals, alloys, and semiconductors with high-melting-point materials as templates. In the gap between the polystyrene pellets; the polystyrene pellets used as templates are removed by high-temperature roasting or tetrahydrofuran extraction, and highly ordered, large-pore, high-specific surface pure metals, alloys, semiconductors, etc. Melting point photonic crystal materials. Specific steps are as follows:

(1) At room temperature, the solution dispersed with polystyrene beads of uniform size is covered on a flat substrate.

The weight concentration of the solution of ethylene pellets is 5%-30%;

(2) Let the solvent for dispersing polystyrene beads volatilize under vacuum conditions, and after volatilization, the polystyrene beads

It is stacked on the substrate in a face-centered cubic stacking manner.

(3) The substrate covered with the polystyrene ball layer is subjected to a coating process, and metals, alloys, and semiconductors are highly coated.

The melting point material is filled into the gap of the polystyrene ball as a template agent;

(4) The substrate treated by the coating process is immersed in THF or baked at 500-600°C for 4-6 hours,

Remove the polystyrene pellets as templating agent.

In the above method, polystyrene spheres with uniform diameter and good dispersion are used as the macroporous template agent, and polystyrene spheres with diameters ranging from 50nm to 400nm in different specifications can be selected. By making the polystyrene spheres settle naturally in the solution, the polystyrene spheres with different diameters can be respectively arranged into a three-dimensional face-centered cubic structure. It can be confirmed by scanning electron microscopy (SEM) that the aperture of the obtained macroporous photonic crystal material is about 70% of the diameter of the polystyrene sphere as the template, and the diameter of the photonic crystal material can be adjusted by changing the diameter of the polystyrene sphere. aperture. Large holes in metals, alloys, and semiconductor photonic crystal materials are also stacked in a three-dimensional face-centered cubic structure, and every two holes are connected by a small hole. A continuous, orderly and defect-free bulk material can reach a size of 0.5mm×0.5mm×0.5mm.

In the above method, the coating film can adopt an electrochemical plating process, and the substrate can use conductive glass. Specifically, immerse the substrate in the electroplating solution, conduct electricity under the condition of 0.1-0.5 ampere/square decimeter, and perform electroplating.

In the above method, the ion sputtering spraying process can also be used for the coating film, and a silicon wafer is used as the substrate. Specifically, the substrate is placed in an ion sputtering apparatus, vacuumized and electrosprayed.

In the above method, the pulsed laser sputtering process can also be used for the coating, and a silicon wafer is used as the substrate. Specifically, the silicon substrate is placed in a pulsed laser sputtering apparatus, and in a high vacuum environment, the pulsed laser is irradiated on the target material for sputtering.

In the above method, high melting point materials such as metals, alloys, and semiconductors are generally gold, platinum, nickel, tin-cobalt, silicon, aluminum nitride, and the like.

In the present invention, an electrochemical method is adopted to infiltrate various metals and alloy materials into the gaps of polystyrene balls as templates. Using conductive glass as a substrate, drop a solution dispersed with polystyrene balls on its conductive surface, and control the amount of dropping solution to change the thickness of the obtained polystyrene layer, and then change the thickness of the final photonic crystal material , the thickness can reach several millimeters. Specifically, the conductive glass covered with polystyrene balls is made into an electrode, which is connected to the cathode of the electroplating instrument, and another platinum electrode is connected to the anode of the electroplating instrument. Immerse the two electrodes in the electroplating solution, and conduct electroplating by energizing at a low current density of 0.1 ampere/square decimeter. By changing the energization time, photonic crystal hole materials with different thicknesses can be obtained on the conductive surface of the conductive glass. The metal and alloy film materials obtained by electrochemical methods have certain mechanical stability, and even this film can be removed from the conductive glass.

In the present invention, when various metals and alloy materials are infiltrated into the gap of polystyrene balls as templates by electrochemical methods, various commercial electroplating solutions can be conveniently used, so this method can be widely used Preparation of photonic crystals of various metals, alloys and semiconductor hole materials with high melting point and high refractive index.

In the present invention, when the ion sputtering method is used to infiltrate various metals and alloy materials into the gaps of the polystyrene balls as the template, after the flat silicon wafer as the substrate is cleaned, the polystyrene powder dispersed on the silicon wafer is added dropwise. For the solution of styrene spheres, the polystyrene spheres are allowed to settle naturally under vacuum. After the solvent evaporates, the polystyrene spheres are piled up on the silicon wafer to form a three-dimensional face-centered cubic structure. Specifically, the silicon wafer is put into a vacuum spraying apparatus, and after vacuuming, it is electrosprayed, and after spraying, it is roasted at a high temperature or extracted with THF, and the polystyrene ball as a template is removed, and the same can be obtained Photonic crystals of porous materials with large-area ordered structures. By changing the target material in the vacuum spraying apparatus, photonic crystals of different metals and alloy hole materials can be obtained.

In the present invention, when the pulsed laser sputtering method is used to infiltrate various semiconductors and alloy materials into the gap of the polystyrene ball as the template, the flat silicon wafer covered with the polystyrene ball is put into the pulsed laser sputtering device In a high-vacuum environment, the target material is irradiated with a pulsed laser. The target material is released from the surface of the material in the form of high-energy particles, and moves to the polystyrene ball through the vacuum chamber, and infiltrates from the accumulation gap of the polystyrene ball. After removing polystyrene balls by high-temperature calcination, photonic crystal materials such as semiconductors and alloys with ordered holes can be obtained. Using this method, changing the target material in the pulsed laser sputtering apparatus can easily infiltrate various hard materials, such as silicon, aluminum nitride, etc., into the gap between polystyrene balls.

In the present invention, the prepared various porous materials have a three-dimensional ordered pore structure, so they have a forbidden effect on light of a certain wavelength. The prohibition effect of the crystal is enhanced, and the prohibition rate can reach more than 80%. Adjusting the diameter (50---400nm) of the small ball used as the template can change the hole size of the obtained photonic crystal, so that the wavelength of the forbidden light can be changed. The wavelength range of the forbidden light can be from the visible region to the infrared region, and this material can be applied in the preparation of optical devices and other aspects.

Detailed ways

The following application examples will further elaborate the present invention:

Embodiment 1, first, cut the conductive glass into a size of 1 square centimeter, carefully wash away the dirt on the conductive surface of the conductive glass with detergent, and then wash it with water, then put the conductive glass into ethanol and ultrasonically clean it until it is conductive The glass surface is completely wetted in water.

A proper amount of solution (10% by weight) dispersed with polystyrene spheres with a size of 300 nm was dropped onto the conductive surface of the cleaned conductive glass. Put it in a vacuum desiccator, evacuate it, and let it stand until the solvent evaporates completely. At this time, polystyrene spheres with uniform diameters have been arranged in a three-dimensional face-centered cubic structure on the surface of the conductive glass.

Wires are connected to conductive glass to make electrodes.

Connect the prepared electrode to the cathode of the electroplating apparatus, and connect the platinum electrode to the anode of the electroplating apparatus at the same time. Both cathode and anode are immersed in the plating bath. A plating solution for electroplating metal nickel is added in the electroplating tank. The composition of the plating solution is: 120g/L NiSO ₄ ·6H ₂ O, 15g/L H ₃ BO ₃ and 15g/L NH ₄ Cl. Electroplating at room temperature. Gradually increase the current until the current density is 0.1 A/dm2. In order to prevent too much cathode gas from being generated on the cathode after the current density is too high and affect the quality of the polystyrene spherical layer, the current density is generally maintained below 0.1 ampere/square decimeter. After 20 minutes, power off. Carefully remove the conductive glass. At this point a layer of metallic nickel had been plated in the gaps between the polystyrene balls.

The removed conductive glass was immersed in tetrahydrofuran to remove the polystyrene balls, and removed after 30 minutes. Then immerse in new tetrahydrofuran for extraction once more. After removal, wash in ethanol. On the conductive glass, a layer of hole material photonic crystal of nickel metal can be obtained.

Prolonging the electroplating time can obtain a thicker electroplating layer, and the obtained metal nickel layer can be peeled off from the conductive glass, and then extracted and cleaned. Metallic photonic crystal films of porous materials can be produced.

It can be seen from the electron micrographs that the diameter of the obtained macropore reaches 210nm, which is about 30% smaller than the diameter of the polystyrene ball. Scanning electron microscope test results show that the arrangement of pores is a three-dimensional ordered face-centered cubic structure. The X-ray diffraction test results show that the obtained film composition is the crystal of nickel metal. Electron spectroscopy test results also show that after extraction, the composition of the obtained porous material is more than 95% nickel, and there are a small amount of oxygen and carbon.

Embodiment 2, cleaning, covering polystyrene balls with a diameter of 400nm, and making electrodes are according to the procedure of Embodiment 1.

A plating solution for electroplating metal platinum is added to the electroplating tank. The plating solution is a commercial electroplating solution, which contains potassium chloroplatinate and additives. Conduct electroplating in a 40-degree water bath. Other conditions and process are all according to embodiment 1 procedure.

The resulting macropores have a pore size of 280 nm, which is about 30% smaller than the diameter of polystyrene spheres. The scanning electron microscope test results show that the arrangement of the pores is a three-dimensional ordered face-centered cubic structure. X-ray diffraction test shows that the obtained film composition is the crystal of metallic platinum. The electron spectrum test also shows that after the extraction, more than 95% of the composition of the obtained porous material is platinum, and there are a small amount of oxygen and carbon.

Embodiment 3, cleaning, covering polystyrene balls with a diameter of 270nm, and making electrodes are according to the procedure of Embodiment 1.

A plating solution for electroplating tin-cobalt alloy is added into the electroplating tank. The plating solution is a commercial plating solution containing 20g/L SnCl ₂ , 8g/L CoCl ₂ , 220g/L K ₄ P ₂ O ₇ ·3H ₂ O and 30g/L additives. Conduct electroplating in a 40-degree water bath. Other conditions and process are all according to embodiment 1 procedure.

The resulting macropores have a pore size of 190 nm, which is about 30% smaller than the diameter of polystyrene spheres. The scanning electron microscope test results show that the arrangement of the pores is a three-dimensional ordered face-centered cubic structure. X-ray diffraction test shows that the obtained film composition is the crystal of tin-cobalt alloy. The electron spectrum test also shows that after the extraction, the composition of the obtained porous material is 68% tin, 23% cobalt, and a small amount of oxygen and carbon.

In Example 4, a silicon wafer was used as the substrate, and the cleaning process and the process of covering polystyrene balls with a diameter of 210 nm were all in accordance with the procedures in Example 1.

Place the silicon wafer covered with polystyrene spheres into the sputter ion coater. Gold foil is used as the target material in the ion sputtering apparatus. Vacuumize to a vacuum degree of 0.1---0.05torr. Electrospraying, the current is kept at 2---3 mA. After 10 minutes of sputtering, stop and take out the silicon wafer.

The polystyrene balls were removed by firing at 500°C for 5 hours in an air atmosphere.

It can be seen from electron microscope photos that the obtained macropores have a diameter of 140 nm, which is about 30% smaller than the diameter of polystyrene spheres. And it has an orderly arranged pore structure. X-ray diffraction test shows that the obtained film composition is the crystal of metal gold. The electron spectrum test also shows that after sintering, more than 95% of the composition of the obtained porous material is gold, and there are also a small amount of oxygen and carbon.

In Example 5, a silicon wafer was used as the substrate, and the cleaning process and the process of covering polystyrene balls with a diameter of 130 nm were all in accordance with the procedures in Example 1.

A silicon wafer covered with polystyrene spheres is placed in a pulsed laser sputtering coater. The target material in the pulsed laser sputtering sprayer is high-purity silicon wafer. After evacuating to a high vacuum, start to irradiate the target material high-purity silicon wafer with a pulse frequency of 10 Hz and a laser beam with a wavelength of 532 nm. The target material is released from the surface of the material in the form of high-energy particles, and moves to the polystyrene ball through the vacuum chamber, and infiltrates from the accumulation gap of the polystyrene ball. After an hour, stop.

The polystyrene balls were removed by firing at 550°C for 5 hours under a nitrogen atmosphere. Remove the silicon wafer.

X-ray diffraction test shows that the obtained film composition is the crystal of semiconductor silicon material. The electron spectrum test also shows that after sintering, the composition of the obtained porous material is more than 95% silicon, and there are also a small amount of oxygen and carbon. The pore diameter of the material reaches about 90nm.

Embodiment 6, adopting silicon chip to do substrate, cleaning process and the process of covering the polystyrene ball that diameter is 60nm all according to

Example 1 procedure.

A silicon wafer covered with polystyrene spheres is placed in a pulsed laser sputtering coater. The target material in the pulsed laser sputtering apparatus is replaced by aluminum nitride bulk material. After evacuating to a high vacuum, start to irradiate the target material with a pulse frequency of 10 Hz and a laser beam with a wavelength of 532 nm, and stop after one hour.

The polystyrene balls were removed by firing at 550°C for 4.5 hours under a nitrogen atmosphere. Remove the silicon wafer.

X-ray diffraction test shows that the obtained film composition is the crystal of aluminum nitride material. The pore size of the material reaches about 40nm.

Claims (4)

1. A method for preparing a photonic crystal material with a high melting point, using three-dimensional ordered polystyrene beads as a template, characterized in that the specific steps are as follows: (1) At room temperature, a solution dispersed with polystyrene beads of uniform size is covered on a flat substrate, and the weight concentration of the polystyrene beads solution is 5%-30%; (2) The solvent for dispersing the polystyrene beads is volatilized under vacuum conditions, and after the volatilization is dry, the polystyrene beads are piled up in a face-centered cubic stacking mode on the substrate; (3) The substrate covered with the polystyrene pellet layer is subjected to a coating process, and metals, alloys, and semiconductor high-melting-point materials are filled into the gaps of the polystyrene pellets as templates; (4) The substrate processed by the coating process is immersed in tetrahydrofuran or baked at 500-600° C. for 4-6 hours to remove the polystyrene pellets as the template agent. 2. The preparation method according to claim 1, characterized in that the coating process in step (3) adopts electrochemical plating technology, and the substrate adopts conductive glass. 3. The preparation method according to claim 1, characterized in that the coating process in step (3) adopts ion sputtering technology, and the substrate adopts a silicon wafer. 4. The preparation method according to claim 1, characterized in that the coating process in step (3) adopts pulsed laser sputtering technology, and the substrate adopts a silicon wafer.