A method for preparing AlN nanofilm

Abstract

The present invention specifically relates to a method for preparing an AlN nanofilm and the prepared AlN nanofilm. The method for preparing the AlN nanofilm comprises the following steps: forming an Al film and an aluminum oxide film on the surface of a multilayer graphene in sequence, then placing the multilayer graphene on a nitrogen atmosphere, obtaining an AlN film through a carbon thermal reduction reaction and a nitridation reaction, and finally removing excess carbon to obtain an AlN nanofilm. The method is simple in process and can successfully prepare a large-sized AlN nanofilm that is not easy to crack.

Description

Technical Field

[0001] The invention relates to the technical field of preparation of AlN nanofilms, and in particular to a method for preparing AlN nanofilms. Background Art

[0002] AlN is an important IIIA wide bandgap semiconductor optoelectronic material with excellent high thermal conductivity, low piezoelectric constant, thermal expansion coefficient matching that of Si, excellent chemical stability and low electron affinity. It has potential application prospects in the manufacture of nano optoelectronic devices. At the same time, low-dimensional nanomaterials have high aspect ratios and specific areas, which are conducive to enhancing photocatalytic activity. Low-dimensional nanomaterials are easy to bend in a controllable manner, which is conducive to the manufacture of flexible optoelectronic devices and are widely used in devices such as ultraviolet detectors and flat panel displays. Therefore, low-dimensional flexible AlN nanomaterials have become a hot topic in domestic and foreign academic and business circles, and have attracted attention from many fields.

[0003] At present, the main synthetic methods for preparing AlN nanomaterials are: (1) Nanotube template method: using nanotubes as templates, and then using physical or chemical methods to deposit the target material on the corresponding position of the template, and then removing the template to obtain the target material with the same nanostructure. (2) Vapor deposition method: Usually pure aluminum (Al) is used as the target material. By applying a high voltage to the aluminum target, argon atoms are ionized into plasma. These argon ions are driven by the electric field and hit the aluminum target at high speed, which will "knock" the aluminum atoms off the target surface. At the same time, nitrogen is introduced into the vacuum chamber to react with the sputtered aluminum atoms to form an AlN film, forming an AlN nanofilm on the substrate surface.

[0004] The above method for preparing AlN nanofilms has a complex process and high cost. In addition, the size of the nanofilms prepared so far is usually below 1000 nm, and the preparation of AlN nanofilms of larger sizes is quite difficult. Summary of the invention

[0005] The invention provides a method for preparing an AlN nanofilm. The method is conducive to the preparation of a large-size AlN nanofilm, has a simple process, and the prepared nanofilm is not prone to cracking.

[0006] The invention provides a method for preparing an AlN nanofilm, comprising the following steps: sequentially forming an Al film and an aluminum oxide film on the surface of a multilayer graphene, then placing the multilayer graphene under nitrogen atmosphere conditions, obtaining the AlN film through carbon thermal reduction reaction and nitridation reaction, and finally removing excess carbon to obtain the AlN nanofilm.

[0007] According to the preparation method described above, the thickness of the Al film is 10-30 nm, and the thickness of the aluminum oxide film is 200-500 nm.

[0008] According to the above-mentioned preparation method, the temperature of the carbon thermal reduction reaction and the nitridation reaction is 1350-1600°C.

[0009] According to the preparation method described above, the method for removing excess carbon is calcination in an air atmosphere.

[0010] According to the preparation method described above, both the Al film and the aluminum oxide film are formed by magnetron sputtering.

[0011] According to the preparation method described above, the conditions for forming Al thin film by magnetron sputtering are: reaction chamber pressure of 1-1.5Pa, argon gas flow rate of 30-60sccm; target power of 50-100W, duty cycle of 70-90%, sputtering time of 20-100min, and substrate rotation rate of 10-18r / min.

[0012] According to the preparation method described above, the conditions for forming an aluminum oxide film by magnetron sputtering are: the reaction chamber pressure is 1-2Pa, the argon gas flow rate is 30-60sccm, the target power is 50-100W, the duty cycle is 70-90%, the sputtering time is 20-40 min, and the substrate rotation rate is 10-18r / min.

[0013] The preparation method described above also includes a step of sputtering pretreatment to clean the target material.

[0014] According to the preparation method described above, the sputtering pretreatment method is: the graphene-covered substrate and the Al 2 O 3 The target materials are placed in a magnetron sputtering reaction system for sputtering pretreatment. After ignition, sputtering is continued for a period of time to clean the target surface.

[0015] According to the above-mentioned preparation method, the sputtering pretreatment conditions are: the vacuum chamber pressure is pumped to 5×10 -4 Pa, introduce argon into the vacuum chamber, set the reaction chamber pressure to 1-3Pa, the power to 20-50W, and continue sputtering for 3-10 minutes after ignition.

[0016] According to the preparation method described above, graphene is covered on the substrate.

[0017] The method for preparing AlN nanofilm provided by the present invention first forms an Al film and an aluminum oxide film on multilayer graphene in sequence, then converts Al and aluminum oxide into AlN through a carbon thermal reduction reaction and a nitridation reaction, and removes excess carbon. The method has a simple process and can successfully prepare a nanofilm with a size of up to 50×50 μm, and the nanofilm is not prone to cracking. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 Schematic diagram of the magnetron sputtering process principle;

[0019] Figure 2 is the XRD pattern of the AlN nanofilm prepared in Example 1 of the present invention;

[0020] Figure 3 is a SEM image of the longitudinal section of the AlN nanofilm prepared in Example 1 of the present invention;

[0021] Figure 4 This is a SEM image of the surface of the AlN nanosheet prepared in Example 1 of the present invention;

[0022] Figure 5 This is a SEM surface image of the nanofilm prepared in Comparative Example 1 of the present invention;

[0023] Figure 6 This is the XRD diagram of the nanofilm prepared in Comparative Example 3 of the present invention. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solutions and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] The invention provides a method for preparing an Al nanofilm, comprising the following steps: sequentially forming an Al film and an aluminum oxide film on the surface of a multilayer graphene, then placing the multilayer graphene on a nitrogen atmosphere, obtaining an AlN film through a carbon thermal reduction reaction and a nitridation reaction, and finally removing excess carbon to obtain the AlN nanofilm.

[0026] The present invention uses multi-layer graphene to ensure that the graphene is excessive, and then sequentially forms an Al film and an aluminum oxide film on the graphene surface. At this time, there are two layers of film on the graphene surface, one Al film and one aluminum oxide film. Then, the Al film and the aluminum oxide film are completely converted into AlN through a carbon thermal reduction reaction and a nitridation reaction, and an AlN nanofilm is obtained. In this method, by first forming an Al film base layer and then forming an aluminum oxide film layer, the O generated during the direct deposition of the aluminum oxide film can be avoided. 2- The etching phenomenon occurs on graphene, which leads to the problem of incomplete breakage of the subsequent AlN nanofilm. This method can successfully prepare nanofilms with a size of up to 50×50μm.

[0027] The study found that when the thickness of the Al film is 10-30nm and the thickness of the aluminum oxide film is 200-500nm, the purity of the prepared AlN nanofilm can be guaranteed to be high, because under this condition, the Al film and the aluminum oxide film can be completely converted into AlN under the action of graphene. For example, the thickness of the Al film can be a parameter within the range of 10nm, 12nm, 14nm, 16nm, 18nm, 20nm, 22nm, 24nm, 26nm, 28nm, 30nm or any two thereof. The thickness of the aluminum oxide film can be a parameter within the range of 200nm, 250nm, 300nm, 350nm, 400nm, 450nm and 500nm or any two thereof.

[0028] By adopting the method described in the present invention, a nano film with a size of 50×50 μm and a purity of more than 99% can be successfully prepared, and the nano film is not prone to cracking.

[0029] Carbon thermal reduction reaction refers to a reaction with carbon as a reducing agent. In the present application, carbon is used as a reducing agent to convert aluminum oxide into aluminum. Nitriding reaction is the reaction of aluminum with nitrogen to convert it into AlN. The reducing agent in the present application is graphene, and the carbon thermal reduction reaction and the nitridation reaction can be carried out simultaneously, and the temperature can be controlled to be 1350-1600°C. Specifically, the temperature can be a parameter within the range of 1350°C, 1400°C, 1450°C, 1500°C, 1550°C, 1600°C or any two thereof. For example, in some specific embodiments, graphene covered with an Al film and an aluminum oxide film is placed in a carbon tube furnace, nitrogen is introduced, the temperature is controlled at 1400°C, and the temperature is lowered after constant temperature heating for 3 hours to complete the carbon thermal reduction reaction and the nitridation reaction.

[0030] After the carbonization reduction reaction and the nitridation reaction are completed, the excess carbon can be removed by conventional carbon removal methods, such as the commonly used calcination method. For example, calcination at 500° C. for 1 hour in an air atmosphere can completely remove the excess carbon.

[0031] In the present invention, the formation method of the Al film and the aluminum oxide film is not limited and can be realized by conventional methods in the art. Preferably, the formation is performed by magnetron sputtering, because the magnetron sputtering formation method is convenient for accurately controlling the thickness of the Al film and the aluminum oxide film on the graphene surface, and can make them evenly distributed and covered on the graphene, which is conducive to the subsequent reaction to proceed fully.

[0032] The conditions for forming Al thin film by magnetron sputtering are as follows: the reaction chamber pressure is 1-1.5Pa, the argon flow rate is 30-60sccm; the target power is 50-100W, the duty cycle is 70-90%, the sputtering time is 20-100 min, and the substrate rotation rate is 10-18r / min. Under this condition, while ensuring smooth ignition, the deposition speed of the film is fast and the uniformity is good, and the compactness is high. In some specific embodiments, the conditions for forming Al thin film by magnetron sputtering are: the reaction chamber pressure is 1.5 Pa, the argon flow rate is 50 sccm, the target power is 50W, the duty cycle is 80%, the substrate rotation rate is 15r / min, and the sputtering time is 20 min. When forming Al thin film by magnetron sputtering, the key parameters are the reaction chamber pressure, target power and sputtering time. The reaction chamber pressure is controlled at 1-1.5Pa, specifically 1Pa, 1.2Pa, 1.3Pa, 1.4Pa, 1.5Pa or any two of the above parameters, and the target power is controlled at 50-100W, specifically 50W, 70W, 80W, 90W, 100W or any two of the above parameters. Under the parameter conditions, the specific sputtering time determines the thickness of the film, and the thickness of the sputtered film can be achieved by adjusting the sputtering time.

[0033] The conditions for forming an aluminum oxide film by magnetron sputtering are: a reaction chamber pressure of 1-2Pa, an argon gas flow rate of 30-60sccm, a target power of 50-100W, a duty cycle of 70-90%, a sputtering time of 20-40 min, and a substrate rotation rate of 10-18r / min. Under these conditions, the aluminum oxide film formed has good uniformity and high compactness. In some specific embodiments, the conditions for forming an aluminum oxide film by magnetron sputtering are: a target power of 75w, a duty cycle of 80%, and a substrate rotation rate of 15r / min. When forming an aluminum oxide film by magnetron sputtering, the key parameters are also the reaction chamber pressure, target power and sputtering time. The reaction chamber pressure is controlled at 1-2Pa, specifically 1Pa, 1.2Pa, 1.3Pa, 1.4Pa, 1.5Pa, 1.8Pa, 2Pa or any two of the above parameters, and the target power is controlled at 50-100W, specifically 50W, 70W, 80W, 90W, 100W or any two of the above parameters. Under this parameter condition, the sputtered film thickness can also be achieved by adjusting the sputtering time.

[0034] In order to further better ensure the quality of the obtained film, the target material is usually cleaned and pretreated, such as by ion source bombardment. In some specific embodiments, the method of ion source bombardment pretreatment is: the graphene-covered substrate and the target material are placed in a magnetron sputtering reaction system for sputtering pretreatment, and sputtering is continued for a period of time after ignition to complete the cleaning of the target surface.

[0035] Usually, the pretreatment conditions are as follows: the vacuum chamber pressure is pumped down to 5×10 -4 Pa, introduce argon into the vacuum chamber, set the reaction chamber pressure to 1-3Pa, the power to 20-50W, and continue sputtering for 3-10min after ignition. For example, in some specific embodiments, the pretreatment conditions are: place the graphene-covered substrate and the target material in the magnetron sputtering reaction system, pump the vacuum chamber pressure to 5×10 -4 Pa, introduce 150sccm of argon into the vacuum chamber, set the reaction chamber pressure to 3Pa, the power to 30W, and continue sputtering for 5 minutes after ignition.

[0036] In the present invention, graphene is usually coated on quartz or other high temperature resistant substrates. Multilayer graphene is arranged on the substrate to ensure that carbon is in a slightly excessive state and to ensure complete reaction.

[0037] The method for preparing Al nanofilm of the present invention is described in detail below through specific examples.

[0038] Example 1

[0039] This embodiment provides a method for preparing an AlN nanofilm and the prepared AlN nanofilm, which are specifically as follows:

[0040] (1) Preprocessing

[0041] Ion source bombardment cleaning: A quartz substrate (2.5*1.5 cm) covered with multilayer graphene was placed in a magnetron sputtering reaction system. 2 O 3 The target material is placed at the corresponding position of the RF target. After checking whether it is short-circuited or broken, the front baffle of the RF target is closed, the cavity is closed, and the vacuum chamber is pumped down to 5×10 -4 Below Pa, introduce 150sccm of high-purity argon into the vacuum chamber. In order to facilitate ignition, set the reaction chamber pressure to 3Pa, turn on the target position switch, set the power to 30W, and continue sputtering for 5 minutes after observing the ignition to clean the target surface.

[0042] (2) Magnetron sputtering aluminum oxide layer

[0043] In order to prevent sputtering of Al 2 O 3 When 2-Ions bombard the graphene film on the surface of the substrate, causing the graphene film to be etched. First, the reaction chamber pressure of the magnetron sputtering system was adjusted to 1.5Pa, the Ar gas flow rate was set to 50sccm, the target power was 50W, the duty cycle was 80%, and the substrate rotation rate was 15r / min. The aluminum target was sputtered by magnetron sputtering to sputter a 20nm Al film on the graphene surface, and then cooled after sputtering. Then, the Al target was sputtered using a medium-frequency magnetron sputtering power supply. 2 O 3 The target was continuously sputtered, wherein the target power was set to 50 W, the duty cycle was 80%, and the substrate rotation rate was 15 r / min, and an aluminum oxide film with a thickness of 300 nm was sputtered on the graphene-covered substrate. Subsequently, the target power was turned off, the baffle and the substrate were rotated, the gas path was closed, and the substrate was cooled with the furnace for 30 min.

[0044] (3) Heat treatment

[0045] The Al film, Al 2 O 3 The substrate of the film is placed in a carbon tube furnace, nitrogen is introduced, the temperature is raised to 1400°C, and the temperature is lowered after constant heating for 3 hours, so that carbon thermal reduction reaction and direct nitridation reaction occur. The calcined sample is then calcined at 500°C for 1 hour in an air atmosphere to remove excess carbon, and the sample is taken out after cooling.

[0046] Scanning electron microscope observation shows that the AlN nanofilm on the substrate is broken into multiple parts. In a fragment with the largest size, a maximum rectangle is drawn, and the AlN nanofilm with a size of 50×50 μm is obtained. The nanofilm is intact and not cracked ( Figure 3 , 4 is a partial SEM picture). XRD analysis shows that the nanofilm has extremely high purity (see Figure 2 ).in, Figure 1 Schematic diagram of magnetron sputtering process principle. Figure 2 is the XRD pattern of the AlN nanofilm prepared in this example. Figure 3 This is a SEM image of the longitudinal section of the AlN nanofilm prepared in this example. Figure 4 This is a SEM image of the surface of the AlN nanofilm prepared in this example.

[0047] Example 2

[0048] This embodiment provides a method for preparing an AlN nanofilm and the prepared AlN nanofilm, which are specifically as follows:

[0049] (1) Preprocessing

[0050] Ion source bombardment cleaning: The silicon nitride substrate (2.5*1.5cm) covered with multilayer graphene was placed in a magnetron sputtering reaction system. 2 O3 The target material is placed at the corresponding position of the RF target. After checking whether it is short-circuited or broken, the front baffle of the RF target is closed, the cavity is closed, and the vacuum chamber is pumped down to 5×10 -4 Below Pa, introduce 150sccm of high-purity argon into the vacuum chamber. In order to facilitate ignition, set the reaction chamber pressure to 3Pa, turn on the target position switch, set the power to 30W, and continue sputtering for 5 minutes after observing the ignition to clean the target surface.

[0051] (2) Magnetron sputtering aluminum oxide layer

[0052] In order to prevent sputtering of Al 2 O 3 When 2- Ions bombard the graphene film on the surface of the substrate, causing the graphene film to be etched. First, the reaction chamber pressure of the magnetron sputtering system was adjusted to 1.5Pa, and the Ar gas flow rate was set to 50sccm. The aluminum target was sputtered by magnetron sputtering. The target power was 50 W, the duty cycle was 80%, and the substrate rotation rate was 15r / min. A 20nm Al film was sputtered on the graphene surface by magnetron sputtering. After sputtering, it was cooled. Then, the Al was sputtered using a medium-frequency magnetron sputtering power supply. 2 O 3 The target was continuously sputtered, wherein the target power was set to 50 W, the duty cycle was 80%, and the substrate rotation rate was 15 r / min, and an aluminum oxide film with a thickness of 200 nm was sputtered on the graphene-covered substrate. Subsequently, the target power was turned off, the baffle and the substrate were rotated, the gas path was closed, and the substrate was cooled with the furnace for 30 min.

[0053] (3) Heat treatment

[0054] Covered with Al 2 O 3 The substrate of the film is placed in a carbon tube furnace, nitrogen is introduced, the temperature is raised to 1400°C, and the temperature is lowered after constant heating for 3 hours, so that carbon thermal reduction reaction and direct nitridation reaction occur. The calcined sample is then calcined at 500°C for 1 hour in an air atmosphere to remove excess carbon, and the sample is taken out after cooling.

[0055] Observation under a scanning electron microscope showed that the largest nanofilm obtained had a size of 45×60 μm, and the nanofilm was intact without cracks.

[0056] Comparative Example 1

[0057] This comparative example provides a method for preparing an AlN nanofilm, which is different from Example 1 in that only an aluminum oxide film is sputtered on a quartz substrate covered with multilayer graphene, and an Al film is not sputtered. The specific method is as follows:

[0058] (1) Preprocessing

[0059] Ion source bombardment cleaning: A quartz substrate (2.5*1.5 cm) covered with multilayer graphene was placed in a magnetron sputtering reaction system. 2 O 3 The target material is placed at the corresponding position of the RF target. After checking whether it is short-circuited or broken, the front baffle of the RF target is closed, the cavity is closed, and the vacuum chamber is pumped down to 5×10 -4 Below Pa, introduce 150sccm of high-purity argon into the vacuum chamber. In order to facilitate ignition, set the reaction chamber pressure to 3Pa, turn on the target position switch, set the power to 30W, and continue sputtering for 5 minutes after observing the ignition to clean the target surface.

[0060] (2) Magnetron sputtering aluminum oxide layer

[0061] Using medium frequency magnetron sputtering power supply to 2 O 3 Target sputtering, wherein the target power is set to 50 W, the duty cycle is 80%, the substrate rotation rate is 15 r / min, and an aluminum oxide film with a thickness of about 200 nm is sputtered on the graphene-covered substrate. Subsequently, the target power is turned off, the baffle and the substrate are rotated, the gas path is closed, and the substrate is cooled with the furnace for 30 minutes.

[0062] (3) Heat treatment

[0063] Covered with Al 2 O 3 The substrate of the film is placed in a carbon tube furnace, nitrogen is introduced, the temperature is raised to 1400°C, and the temperature is lowered after constant heating for 3 hours, so that carbon thermal reduction reaction and direct nitridation reaction occur. The calcined sample is then calcined at 500°C for 1 hour in an air atmosphere to remove excess carbon, and the sample is taken out after cooling.

[0064] Observation under a scanning electron microscope shows that the obtained 2 Different fine AlN nanosheets, the results are as follows Figure 5 As shown. The reason may be that during the magnetron sputtering process, O 2- Bombarding graphene causes the graphene film to be etched incompletely, so the prepared AlN nanosheets have defects of small size and incompleteness.

[0065] Comparative Example 2

[0066] This comparative example provides a method for preparing an AlN nanofilm, which is different from Example 1 in that only an aluminum film is sputtered on a quartz substrate covered with multilayer graphene, and an aluminum oxide film is not sputtered, as follows:

[0067] (1) Preprocessing

[0068] Ion source bombardment cleaning: A quartz substrate (2.5*1.5 cm) covered with multilayer graphene was placed in a magnetron sputtering reaction system. 2 O 3 The target material is placed at the corresponding position of the RF target. After checking whether it is short-circuited or broken, the front baffle of the RF target is closed, the cavity is closed, and the vacuum chamber is pumped down to 5×10 -4 Below Pa, introduce 150sccm of high-purity argon into the vacuum chamber. In order to facilitate ignition, set the reaction chamber pressure to 3Pa, turn on the target position switch, set the power to 30W, and continue sputtering for 5 minutes after observing the ignition to clean the target surface.

[0069] (2) Magnetron sputtering aluminum oxide layer

[0070] First, the reaction chamber pressure of the magnetron sputtering system was adjusted to 1.5 Pa, and the Ar gas flow rate was set to 50 sccm. The aluminum target was sputtered by magnetron sputtering. The target power was 50 W, the duty cycle was 80%, and the substrate rotation rate was 15 r / min. A 20 nm Al film was sputtered on the graphene surface and cooled after sputtering.

[0071] (3) Nitriding treatment

[0072] The substrate covered with Al film was placed in a carbon tube furnace, nitrogen was introduced, the temperature was raised to 1400℃, and the temperature was lowered after constant heating for 3 hours, so that a direct nitridation reaction occurred. The calcined sample was then calcined at 500℃ for 1 hour in an air atmosphere to remove excess carbon, and the sample was taken out after cooling.

[0073] Observation under a scanning electron microscope showed that the largest AlN nanosheet that could be obtained was 15×25 μm, and the cross section had many defects.

[0074] Comparative Example 3

[0075] This comparative example provides a method for preparing an AlN nanofilm and the prepared AlN nanofilm, which is different from Example 1 in that the thickness of the Al film sputtered on the quartz substrate covered with multilayer graphene is 1 μm, and the specific method is as follows:

[0076] 1) Preprocessing

[0077] Ion source bombardment cleaning: A quartz substrate (2.5*1.5 cm) covered with multilayer graphene was placed in a magnetron sputtering reaction system. 2 O 3 The target material is placed at the corresponding position of the RF target. After checking whether it is short-circuited or broken, the front baffle of the RF target is closed, the cavity is closed, and the vacuum chamber is pumped down to 5×10 -4Below Pa, introduce 50 sccm of high-purity argon into the vacuum chamber. In order to facilitate ignition, set the reaction chamber pressure to 1.5 Pa, turn on the target position switch, set the power to 50 W, and continue sputtering for 5 minutes after observing the ignition to clean the target surface.

[0078] (2) Magnetron sputtering of aluminum layer and aluminum oxide layer

[0079] First, the reaction chamber pressure of the magnetron sputtering system was adjusted to 1.5Pa, and the Ar gas flow rate was set to 50sccm. The aluminum target was sputtered by magnetron sputtering. The target power was 50W, the duty cycle was 80%, and the substrate rotation rate was 15r / min. A 1μm Al film was sputtered on the graphene surface and cooled after sputtering. Then, a medium-frequency magnetron sputtering power supply was used to sputter the Al 2 O 3 The target was continuously sputtered, wherein the target power was set to 50 W, the duty cycle was 80%, and the substrate rotation rate was 15 r / min, and an aluminum oxide film with a thickness of 200 nm was sputtered on the graphene-covered substrate. Subsequently, the target power was turned off, the baffle and the substrate were rotated, the gas path was closed, and the substrate was cooled with the furnace.

[0080] (3) Carbothermal reduction heat treatment

[0081] Covered with Al 2 O 3 The substrate of the film is placed in a carbon tube furnace, nitrogen is introduced, the temperature is raised to 1400°C, and the temperature is lowered after constant heating for 3 hours, so that carbon thermal reduction reaction and direct nitridation reaction occur. The calcined sample is then calcined at 500°C for 1 hour in an air atmosphere to remove excess carbon, and the sample is taken out after cooling.

[0082] XRD analysis results are shown in Figure 6 ,Depend on Figure 6 It can be seen that there is an excess of Al thin film in the nanofilm, that is, what is obtained is a mixed nanosheet of AlN and Al.

[0083] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing an AlN nanofilm, characterized in that: The following steps are involved: An Al film and an aluminum oxide film are sequentially formed on the surface of the multilayer graphene, and then the multilayer graphene is placed in a nitrogen atmosphere to obtain an AlN film through a carbon thermal reduction reaction and a nitridation reaction, and finally the excess carbon is removed to obtain an AlN nanofilm; Wherein, the thickness of the Al film is 10-30nm, and the thickness of the aluminum oxide film is 200-500nm; The temperature of the carbothermal reduction reaction and the nitridation reaction is 1350-1600°C; The method of removing excess carbon is calcination in an air atmosphere; The Al film and the aluminum oxide film are both formed by magnetron sputtering.

2. The method for preparing an AlN nanofilm according to claim 1, characterized in that: The conditions for forming the Al film by magnetron sputtering are: the reaction chamber pressure is 1-1.5 Pa, the argon gas flow rate is 30-60 sccm; the target power is 50-100 W, the duty cycle is 70-90%, the sputtering time is 20-100 min, and the substrate rotation rate is 10-18 r / min; and / or The conditions for forming aluminum oxide film by magnetron sputtering are: reaction chamber pressure of 1-2Pa, argon gas flow rate of 30-60sccm, target power of 50-100W, duty cycle of 70-90%, sputtering time of 20-40 min, and substrate rotation rate of 10-18r / min.

3. The method for preparing AlN nanofilm according to claim 1, characterized in that: It also includes the step of sputtering pre-treatment to clean the target material.

4. The method for preparing an AlN nanofilm according to claim 3, characterized in that: The sputtering pretreatment method is: placing the graphene-covered substrate and the Al2O3 target material in a magnetron sputtering reaction system for sputtering pretreatment, continuing sputtering for a period of time after ignition, and cleaning the target material surface.

5. The method for preparing AlN nanofilm according to claim 4, characterized in that: The conditions for sputtering pretreatment are: the vacuum chamber pressure is pumped down to 5×10 -4 Pa, introduce argon into the vacuum chamber, set the reaction chamber pressure to 1-3Pa, the power to 20-50W, and continue sputtering for 3-10 minutes after ignition.

6. The method for preparing AlN nanofilm according to claim 1, characterized in that: The graphene is coated on the substrate.

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