阅读说明：本技术 一种通过电化学插层制备InSe薄膜的方法 (Method for preparing InSe thin film through electrochemical intercalation ) 是由 冯伟 杨绪轩 刘芝莹 屈栎杭 于 2020-12-16 设计创作，主要内容包括：一种通过电化学插层制备InSe薄膜的方法。本发明属于硒化铟薄膜制备领域。本发明的目的在于解决现有机械剥离法获得的硒化铟随机性较强且产率过低,以及脉冲激光沉积法和化学气相沉积法制备步骤复杂,生产成本高,不适合大规模生产的技术问题。本发明的方法：步骤一、以Pt片为阳极,以铜网包裹的块体InSe为阴极,以四丁基溴化铵溶液为电解液,给阴极施加电压,进行插层反应；步骤二、先高速离心清洗,然后超声处理,再低速离心,保留上清液；步骤三、采用匀胶机以不同转速分阶段旋涂在硅片上,得到InSe薄膜。本发明所制备的InSe产率高,接近70％,表面清洁,薄膜的质量很高,可以进一步浓缩,旋涂成大面积InSe薄膜,用来制备大尺寸、晶圆级光电器件。(A method for preparing InSe film by electrochemical intercalation. The invention belongs to the field of indium selenide film preparation. The invention aims to solve the technical problems that indium selenide obtained by the existing mechanical stripping method has strong randomness and low yield, and a pulse laser deposition method and a chemical vapor deposition method have complex preparation steps and high production cost and are not suitable for large-scale production. The method comprises the following steps: step one, taking a Pt sheet as an anode, taking bulk InSe wrapped by a copper mesh as a cathode, taking tetrabutylammonium bromide solution as electrolyte, and applying voltage to the cathode to perform intercalation reaction; step two, firstly carrying out high-speed centrifugal cleaning, then carrying out ultrasonic treatment, then carrying out low-speed centrifugation, and keeping a supernatant; and step three, spin-coating on the silicon wafer in stages at different rotating speeds by using a spin coater to obtain the InSe thin film. The InSe prepared by the method has high yield which is close to 70 percent, clean surface and high film quality, can be further concentrated and spin-coated into a large-area InSe film, and is used for preparing large-size wafer-level photoelectric devices.)

1. A method for preparing InSe thin film through electrochemical intercalation is characterized by comprising the following steps:

step one, taking a Pt sheet as an anode, taking bulk InSe wrapped by a copper mesh as a cathode, taking tetrabutylammonium bromide solution as electrolyte, and applying voltage to the cathode to perform intercalation reaction;

step two, performing high-speed centrifugation on the product obtained after the intercalation reaction in the step one, pouring out supernatant after centrifugation, then performing high-speed centrifugal cleaning by adopting an organic solvent for multiple times, re-dispersing the precipitate obtained after the high-speed centrifugal cleaning into the organic solvent for ultrasonic treatment, adding the organic solvent again after the ultrasonic treatment for primary low-speed centrifugation, continuing adding the organic solvent after the primary low-speed centrifugation for secondary low-speed centrifugation, and retaining the supernatant after the secondary low-speed centrifugation;

and step three, the supernatant obtained in the step two is spin-coated on a silicon chip in stages at different rotating speeds by a spin coater to obtain the InSe film.

2. The method of claim 1, wherein the solvent of the tetrabutylammonium bromide solution in the first step is N-methylpyrrolidone or dimethylformamide, and the concentration of the tetrabutylammonium bromide in the tetrabutylammonium bromide solution in the first step is 0.01mol/L to 0.015 mol/L.

3. The method of claim 1, wherein the mass of the bulk InSe in the first step is 15-25 mg, and the InSe in the first step is two-dimensional layered semiconductor material with a layer spacing of 0.7-0.9 nm.

4. The method of claim 1, wherein the cathode voltage in step one is-5V to-8V, and the intercalation reaction time in step one is 2h to 2.5 h.

5. The method for preparing InSe thin film through electrochemical intercalation according to claim 1, wherein the rotation speed of the high speed centrifugation in the second step is 4000rpm to 6000rpm, and the centrifugation time is 4min to 6 min.

6. The method for preparing the InSe thin film through the electrochemical intercalation according to claim 1, wherein the number of times of the high-speed centrifugal cleaning by the organic solvent in the second step is 4, the supernatant is poured out after the high-speed centrifugal cleaning by the organic solvent each time, the organic solvent is added again for the next high-speed centrifugal cleaning, and the rotating speed of the high-speed centrifugal cleaning in the second step is 4000rpm to 6000rpm for 4min to 6 min.

7. The method for preparing InSe thin film through electrochemical intercalation according to claim 1, wherein the organic solvent in step two is N-methylpyrrolidone, dimethylformamide or acetonitrile.

8. The method for preparing InSe thin film through electrochemical intercalation according to claim 1, wherein the power of ultrasonic treatment in step two is 400W-500W, the time is 5 s-10 s, the rotation speed and time of the primary low-speed centrifugation and the secondary low-speed centrifugation in step two are the same, the rotation speed is 700 rpm-900 rpm, and the centrifugation time is 4 min-6 min.

9. The method for preparing InSe thin film through electrochemical intercalation according to claim 1, wherein the ratio of the mass of the precipitate to the volume of the organic solvent when the precipitate obtained after high speed centrifugal washing is redispersed in the organic solvent in the second step is (10.5-17.5) mg: 5mL, wherein the ratio of the mass of the precipitate to the volume of the added organic solvent when the organic solvent is added again in the step II for low-speed centrifugation for the first time is (9-16) mg: 5mL, the volume of the organic solvent added in the second low-speed centrifugation in the step two is the same as that of the organic solvent added in the first low-speed centrifugation, and 90 vol.% of the supernatant in the second step is retained.

10. The method for preparing InSe thin film through electrochemical intercalation according to claim 1, wherein the step three is a step-by-step spin coating process with different rotation speeds, which comprises the following steps: firstly spin-coating at a low rotation speed of 1500-2500 rpm for 15-25 s, and then spin-coating at a high rotation speed of 3500-4500 rpm for 35-45 s.

Technical Field

The invention belongs to the field of indium selenide film preparation; in particular to a method for preparing an InSe film through electrochemical intercalation.

Background

A.geim and k.novoselov, manchester university, 2004, used tape to continuously peel off graphite to obtain graphene chips, thereby opening the door to the study of two-dimensional materials. The graphene has ultrahigh electron mobility (20000 cm)²V^-1s^-1) And superior optical properties; however, the graphene has an intrinsic zero band gap energy band structure, so that the field effect transistor and the photoelectric detector have poor performances, and the application of the graphene in the fields of high-performance microelectronics and photoelectrons is greatly limited. With the continuous and deep research of other two-dimensional materials, more and more graphene-like materials show excellent properties. Indium selenide is a III-VI family layered semiconductor material, has high electron mobility and good stability, and becomes a hotspot of current research. The indium selenide thin film with few layers has good flexibility and good photoresponse, and becomes one of candidate materials of a next generation excellent optoelectronic device.

However, the current methods for preparing indium selenide thin films are relatively few. First, the a.patane of the university of nottingham in 2013 obtained indium selenide by a mechanical stripping method, which has high randomness and low yield although the obtained indium selenide has high quality. The pulse laser deposition method and the chemical vapor deposition method have been developed to directly produce the indium selenide thin film, and the equipment required for production is expensive, and the steps are complicated, so that the large-scale production of the indium selenide thin film is still difficult.

Disclosure of Invention

The invention aims to solve the technical problems that indium selenide obtained by the existing mechanical stripping method has strong randomness and low yield, and a pulse laser deposition method and a chemical vapor deposition method have complex preparation steps and high production cost and are not suitable for large-scale production, and provides a method for preparing an InSe film by electrochemical intercalation.

The method for preparing the InSe film through the electrochemical intercalation comprises the following steps:

step one, taking a Pt sheet as an anode, taking bulk InSe wrapped by a copper mesh as a cathode, taking tetrabutylammonium bromide solution as electrolyte, and applying voltage to the cathode to perform intercalation reaction;

step two, performing high-speed centrifugation on the product obtained after the intercalation reaction in the step one, pouring out supernatant after centrifugation, then performing high-speed centrifugal cleaning by adopting an organic solvent for multiple times, re-dispersing the precipitate obtained after the high-speed centrifugal cleaning into the organic solvent for ultrasonic treatment, adding the organic solvent again after the ultrasonic treatment for primary low-speed centrifugation, continuing adding the organic solvent after the primary low-speed centrifugation for secondary low-speed centrifugation, and retaining the supernatant after the secondary low-speed centrifugation;

and step three, the supernatant obtained in the step two is spin-coated on a silicon chip in stages at different rotating speeds by a spin coater to obtain the InSe film.

Further, in the first step, the solvent of the tetrabutylammonium bromide solution is N-methylpyrrolidone or dimethylformamide.

Further limiting, the concentration of the tetrabutylammonium bromide in the tetrabutylammonium bromide solution in the step one is 0.01 mol/L-0.015 mol/L.

Further, the mass of the bulk InSe in the step one is 15 mg-25 mg.

Further defined, the mass of the bulk InSe in step one is 20 mg.

Further, in the first step, the InSe is a two-dimensional layered semiconductor material, and the interlayer distance of the InSe is 0.7 nm-0.9 nm.

Further, in the first step, the InSe is a two-dimensional layered semiconductor material, and the interlayer distance of the InSe is 0.8 nm.

Further, the cathode voltage in the first step is-5V to-8V.

Further limiting, the intercalation reaction time in the step one is 2-2.5 h.

Further limiting, the rotating speed of the high-speed centrifugation in the step two is 4000 rpm-6000 rpm, and the centrifugation time is 4 min-6 min.

Further limiting, the rotating speed of the high-speed centrifugation in the step two is 5000rpm, and the centrifugation time is 5 min.

Further limiting, in the second step, the number of times of high-speed centrifugal cleaning by using the organic solvent is 4.

Further limiting, the specific process of repeatedly adopting the organic solvent to carry out high-speed centrifugal cleaning in the step two is as follows: and (4) after each high-speed centrifugal cleaning by using the organic solvent, pouring out supernatant, and adding the organic solvent again for next high-speed centrifugal cleaning.

Further limiting, the rotating speed of the high-speed centrifugal cleaning in the step two is 4000 rpm-6000 rpm, and the time is 4 min-6 min.

Further limiting, the rotating speed of the high-speed centrifugal cleaning in the step two is 5000rpm, and the time is 5 min.

Further, in the second step, the organic solvent is N-methylpyrrolidone, dimethylformamide or acetonitrile.

Further limiting, the power of the ultrasonic treatment in the step two is 400W-500W, and the time is 5 s-10 s.

And further limiting, the rotation speed and time of the primary low-speed centrifugation and the secondary low-speed centrifugation in the step two are the same, the rotation speed is 700-900 rpm, and the centrifugation time is 4-6 min.

Further limiting, the rotation speed and time of the primary low-speed centrifugation and the secondary low-speed centrifugation in the step two are the same, the rotation speed is 800rpm, and the centrifugation time is 5 min.

Further limiting, when the precipitate obtained after the high-speed centrifugal cleaning is redispersed in the organic solvent in the step two, the ratio of the mass of the precipitate to the volume of the organic solvent is (10.5-17.5) mg: 5 mL.

Further limiting, when the organic solvent is added again in the step two and the low-speed centrifugation is carried out for the first time, the ratio of the mass of the precipitate to the volume of the added organic solvent is (9-16) mg: 5 mL.

Further limiting, the volume of the organic solvent added in the second low-speed centrifugation is the same as that of the organic solvent added in the first low-speed centrifugation.

Further limiting, in step two, 90 vol.% of the supernatant was retained.

Further limiting, the specific process of the step three in which the spin coating is performed in stages at different rotating speeds is as follows: spin coating at low rotation speed and then spin coating at high rotation speed.

Further, the rotation speed of the spin coating at the low rotation speed is 1500 rpm-2500 rpm, and the time is 15 s-25 s.

Further, the spin coating speed at the low speed is 2000rpm, and the time is 20 s.

Further, the rotation speed of the spin coating at the high rotation speed is 3500 rpm-4500 rpm, and the time is 35 s-45 s.

Further, the spin coating speed at the high speed is 4000rpm, and the time is 40 s.

Tetrabutylammonium ion (TBA) in step one of the present invention⁺) When the cathode enters between the InSe layers, the van der Waals force between the InSe layers is overcome, the solution near the platinum sheet electrode is observed to turn yellow, and a large amount of fluffy precipitate substances are arranged at the bottom of the beaker, and the specific reaction is as follows:

and (3) anode reaction: br^--e^-→1/2Br₂

And (3) cathode reaction: InSe + TBA⁺+e^-→(TBA⁺)InSe^-

(TBA⁺)InSe^-→ InSe + tributylamine (tributylamine) + butane

Compared with the prior art, the invention has the following remarkable effects:

the patent adopts an electrochemical intercalation method to strip the synthesized bulk indium selenide (InSe) material into few or even single-layer InSe thin films. The method has high stripping yield and high quality of the obtained InSe film. The method can provide favorable conditions for the preparation of InSe large-size and wafer-level films, can synthesize InSe optoelectronic device arrays, and has a good reference function for the synthesis of other two-dimensional material films, and has the following specific advantages:

1) compared with the traditional preparation method of the InSe film, the InSe film prepared by the invention has high yield which is close to 70 percent, clean surface and high film quality, can be further concentrated and spin-coated into a large-area InSe film, and is used for preparing large-size wafer-level photoelectric devices.

2) The method has the advantages of less process flows, simple operation, low cost of required equipment, good safety and good repeatability of experiments, and is suitable for industrial production.

3) The InSe selected by the invention is a two-dimensional layered semiconductor material, the interlayer spacing of the InSe is about 0.8nm, and the intercalating agent is selected to be matched with the interlayer spacing of the InSe and is easy to separate from the InSe.

4) The invention strips out large InSe thin slices with the thickness of 1.5-10 nm and the size of 7-110 mu m by strictly controlling the working voltage and the electrolyte concentration in the intercalation reaction process.

5) The invention ensures the size of the InSe sheet by controlling the ultrasonic time, and simultaneously obtains a large-size continuous InSe film by stage spin coating, wherein the thickness of the film can be as thin as 1.5nm at most, and the size of the film can be as large as 110 mu m at most.

Drawings

Fig. 1 is an optical image of the InSe thin film obtained in example 1.

Detailed Description

Example 1: the method for preparing the InSe thin film through the electrochemical intercalation according to the embodiment comprises the following steps:

taking a Pt sheet (1cm multiplied by 1cm) as an anode, a copper mesh-wrapped block InSe (20mg) as a cathode, placing the two electrodes in parallel at an interval of 3cm, taking tetrabutylammonium bromide solution (0.01mol/L,20mL) as electrolyte, applying a voltage of-5V to the cathode, and carrying out intercalation reaction for 3 hours; the solvent of the tetrabutylammonium bromide solution is NMP; the InSe is a two-dimensional layered semiconductor material, and the interlayer spacing of the InSe is 0.8 nm;

wherein the preparation process of the bulk InSe comprises the following steps: mixing indium particles and selenium powder in a mass ratio of 1:1.1, putting the mixture into a clean porcelain boat, and putting the porcelain boat into a quartz tube; vacuumizing to remove air in the quartz tube, introducing protective gas (the volume ratio of hydrogen to argon is 2: 8), heating to 300 ℃ within 30min, keeping the temperature for 1h, continuing heating to 660 ℃ within 30min, keeping the temperature for 1h, and naturally cooling to obtain black and bright solid, namely block InSe;

step two, performing high-speed centrifugation on the product obtained after the intercalation reaction in the step one, wherein the rotation speed of the high-speed centrifugation is 5000rpm, the time is 5min, pouring out the supernatant after the centrifugation, then performing high-speed centrifugal cleaning for 4 times by adopting NMP (8mL), the rotation speed of the high-speed centrifugal cleaning is 5000rpm, the time is 5min, pouring out the supernatant after each high-speed centrifugal cleaning by using NMP, adding equal volume of NMP again for next high-speed centrifugal cleaning, redispersing the precipitate obtained after the high-speed centrifugal cleaning in NMP (5mL) for ultrasonic treatment, wherein the power of the ultrasonic treatment is 460W, the time is 10s, adding NMP (5mL) again after the ultrasonic treatment for primary low-speed centrifugation, continuing adding NMP (5mL) after the primary low-speed centrifugation for secondary low-speed centrifugation, and retaining 90 vol.% supernatant after the secondary low-speed centrifugation; the rotation speed and time of the primary low-speed centrifugation and the secondary low-speed centrifugation are the same, the rotation speed is 800rpm, and the centrifugation time is 5 min;

step three, the supernatant obtained in the step two is spin-coated on a silicon chip by stages at different rotating speeds by a spin coater to obtain an InSe film (the thickness of the film is 2 nm-3 nm, the size of the film is 20 mu m-40 mu m, and the yield is 71%); the specific process of the staged spin coating at different rotating speeds comprises the following steps: spin-coat at 2000rpm for 20s and then at 4000rpm for 40 s.

Example 2: the method for preparing the InSe thin film through the electrochemical intercalation according to the embodiment comprises the following steps:

taking a Pt sheet (1cm multiplied by 1cm) as an anode, a copper mesh-wrapped block InSe (20mg) as a cathode, placing the two electrodes in parallel at an interval of 3cm, taking tetrabutylammonium bromide solution (0.015mol/L,20mL) as electrolyte, applying a voltage of-6V to the cathode, and carrying out intercalation reaction for 2 hours; the solvent of the tetrabutylammonium bromide solution is DMF; the InSe is a two-dimensional layered semiconductor material, and the interlayer spacing of the InSe is 0.8 nm;

wherein the preparation process of the bulk InSe comprises the following steps: mixing indium particles and selenium powder in a mass ratio of 1:1.1, putting the mixture into a clean porcelain boat, and putting the porcelain boat into a quartz tube; vacuumizing to remove air in the quartz tube, introducing protective gas (the volume ratio of hydrogen to argon is 2: 8), heating to 300 ℃ within 30min, keeping the temperature for 1h, continuing heating to 660 ℃ within 30min, keeping the temperature for 1h, and naturally cooling to obtain black and bright solid, namely block InSe;

step two, performing high-speed centrifugation on the product obtained after the intercalation reaction in the step one, wherein the rotation speed of the high-speed centrifugation is 5000rpm, the time is 5min, pouring out the supernatant after the centrifugation, then performing high-speed centrifugal cleaning for 4 times by adopting DMF (8mL), the rotation speed of the high-speed centrifugal cleaning is 5000rpm, the time is 5min, pouring out the supernatant after each high-speed centrifugal cleaning by using DMF, adding DMF with the same volume for next high-speed centrifugal cleaning again, re-dispersing the obtained precipitate in DMF (5mL) for ultrasonic treatment, wherein the power of the ultrasonic treatment is 10s, adding DMF (5mL) again after the ultrasonic treatment for primary low-speed centrifugation, continuing adding DMF (5mL) after the primary low-speed centrifugation for secondary low-speed centrifugation, and retaining 90 vol.% supernatant after the secondary low-speed centrifugation; the rotation speed and time of the primary low-speed centrifugation and the secondary low-speed centrifugation are the same, the rotation speed is 800rpm, and the centrifugation time is 5 min;

step three, the supernatant obtained in the step two is spin-coated on a silicon chip by stages at different rotating speeds by a spin coater to obtain an InSe film (the thickness of the film is 2 nm-3 nm, the size of the film is 20 mu m-40 mu m, and the yield is 71%); the specific process of the staged spin coating at different rotating speeds comprises the following steps: spin-coat at 2000rpm for 20s and then at 4000rpm for 40 s.