Resonator based on boron nitride carbon nanotube heterostructure and tuning method

Abstract

The application belongs to the field of resonators, and particularly relates to a resonator based on a boron nitride carbon nanotube heterostructure. The nanometer resonator comprises a boron nitride nanotube and a carbon nanotube arranged in the boron nitride nanotube, and the boron nitride carbon nanotube is a heterostructure; the boron nitride carbon nanotube is provided with an axial electric field at both ends. By applying the axial electric field, the nitrogen atoms and boron atoms in the outer boron nitride nanotube are subjected to the action of the axial electric field force, the nanometer resonator is subjected to axial mechanical deformation, the ratio of the axial load generated to the critical buckling load when the nanometer resonator is fixed at both ends is changed, and finally the resonance frequency is changed, so that the tuning of the nanometer resonator is realized. Compared with the existing single-layer carbon nanotube, the resonance frequency of the boron nitride carbon nanotube heterostructure in the application is significantly improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of nanoresonators, in particular to a resonator based on boron nitride carbon nanotube heterostructure and a tuning method. BACKGROUND

[0002] At present, nanoresonators have played an important role in industrial production and can be used for detection and analysis of physical quantities such as mass, force, pH value, etc.

[0003] Through vibration, the nanoresonator can effectively filter the target signal and reduce the interference of external noise on the target signal. In addition, due to low energy dissipation, the nanoresonator can also collect external energy, so it can be used as an energy collector. Compared with previous nanoresonators, carbon nanotubes have better effects in mass sensing due to their excellent mechanical properties and electrical conductivity, and are widely used in biological detection and gas sensing fields.

[0004] However, the problem of difficult frequency self-adjustment of carbon nanotube resonators has not been effectively solved. The methods proposed by researchers have certain limitations, some are only suitable for cantilever nanoresonators, and some are difficult to tune and difficult to achieve precise tuning. SUMMARY

[0005] The technical problem to be solved by the present application is to solve the existing problems and provide a resonator based on boron nitride carbon nanotube heterostructure and a tuning method.

[0006] The present application provides the following technical scheme: a resonator based on boron nitride carbon nanotube heterostructure, comprising a boron nitride nanotube and a carbon nanotube arranged in the boron nitride nanotube; the boron nitride carbon nanotube is a heterostructure; the boron nitride carbon nanotube is provided with an axial electric field at both ends.

[0007] Further, the boron nitride nanotube is zigzag-shaped; the carbon nanotube is armchair-shaped.

[0008] Further, the heterostructure is a double-layer coaxial heterostructure; the length of the boron nitride nanotube and the carbon nanotube is the same, and the centers of mass coincide.

[0009] Further, the length of the boron nitride carbon nanotube is 10 nm, the difference between the inner and outer radii of the boron nitride nanotube and the carbon nanotube is 3.4 Å, and the up and down floating does not exceed 0.1 Å.

[0010] Further, the boron nitride nanotube and the carbon nanotube are defect-free nanotubes.

[0011] Further, the boron nitride nanotube is (17,0) BNNT, and the carbon nanotube is (5,5) CNT.

[0012] The application further discloses a resonator tuning method based on the boron nitride carbon nanotube heterostructure, and the resonator based on the above boron nitride carbon nanotube heterostructure.

[0013] Further, the resonant frequency of the nanoresonator is obtained through the following steps

[0014] S1, an axial electric field is applied at both ends of the resonator, and an initial displacement of a certain length is applied on the inner and outer two layers of atoms near the centroid of the resonator along the y-axis;

[0015] S2, the initial displacement constraint is released, and the nanoresonator is allowed to freely oscillate for 500 ps to obtain the resonant frequency of the nanoresonator.

[0016] Further, after the initial displacement constraint is released and the nanoresonator is allowed to freely oscillate for 500 ps, the displacement of the centroid of the resonator along the y-axis direction is subjected to fast Fourier transform to obtain the frequency domain variation spectrum of the centroid of the resonator, and the resonant frequency of the nanoresonator is obtained.

[0017] Further, the fixing mode of the nanoresonator is a two-end fixing mode.

[0018] Compared with the prior art, the application has the following beneficial effects:

[0019] 1. By applying an axial electric field, the nitrogen atoms and boron atoms in the outer boron nitride nanotube are subjected to the action of the axial electric field force, the nanoresonator is subjected to axial mechanical deformation, the ratio of the axial load generated to the critical buckling load when the nanoresonator is fixed at both ends changes, and finally the resonant frequency changes, thereby realizing the tuning of the nanoresonator. Compared with the existing single-layer carbon nanotube, the resonant frequency of the boron nitride carbon nanotube heterostructure in the application is significantly improved.

[0020] 2. The resonator provided by the application has the advantages of small size, high sensitivity, significant tuning performance and simple tuning method. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 It is a nanoresonator model under an axial electric field of the application, the block represents the fixed end of the nanoresonator, the arrow represents the direction of the initial displacement applied, and the direction of the figure is the positive direction of the axial electric field;

[0022] Figure 2 It is a heterostructure nanotube after the combination of the boron nitride nanotube, the carbon nanotube and the combination thereof in the specific embodiment of the application; wherein (a) is a (17,0) BNNT; (b) is a (5,5) CNT; and (c) is a CNT(5,5)@BNNT(17,0).

[0023] Figure 3 The image shows the vibration frequency domain diagram of a 10 nm CNT(5,5)@BNNT(17,0) nanoresonator in a specific embodiment of the present invention. The inset shows the displacement of its centroid (COM) along the y-axis.

[0024] Figure 4 The resonant frequencies of (5,5) CNT and CNT(5,5)@BNNT(17,0) nanoresonators under different axial electric field intensities are given. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be described more clearly and completely below with reference to the accompanying drawings in the embodiments of this invention.

[0026] This invention designs a resonator with a boron nitride-carbon nanotube heterostructure, comprising two structures: boron nitride nanotubes and carbon nanotubes, such as... Figure 1 As shown, boron nitride nanotubes are on the outside and carbon nanotubes are on the inside.

[0027] In the heterostructure, boron nitride nanotubes are preferably serrated, i.e. (n,0) BNNT, for example (17,0) BNNT; carbon nanotubes are preferably armchair shaped, i.e. (n,n) CNT, for example (5,5) CNT. Specific Implementation

[0028] The boron nitride carbon nanotube heterostructure nanoresonator provided by this invention operates as follows: a (17,0)BNNT outer tube and a (5,5) CNT inner tube are selected to fabricate a CNT(5,5)@BNNT(17,0) nanoresonator.

[0029] An axial electric field is applied to both ends of the nanoresonator, and an initial displacement of a certain length is applied along the y-axis to the inner and outer layers of atoms near its center of mass. The length of the initial displacement does not exceed 2% of the length of the nanoresonator. Figure 2 As shown in the figure, the arrows indicate the displacement directions of the inner and outer layers of atoms at the center of mass.

[0030] The initial displacement constraint is then released, allowing the nanoresonator to oscillate freely for 500 ps to obtain the resonant frequency of the nanoresonator.

[0031] like Figure 3 As shown, a fast Fourier transform of the displacement of the centroid along the y-axis can be used to obtain the frequency domain variation spectrum of the centroid of the CNT(5,5)@BNNT(17,0) nanoresonator. The frequencies marked in the figure are the resonant frequencies of the CNT(5,5)@BNNT(17,0) nanoresonator.

[0032] Due to the action of the electric field force on the nitrogen atoms and boron atoms in the outer layer of the boron nitride nanotube under the electric field, the nanoresonator is axially mechanically deformed, the ratio of the axial load generated to the critical buckling load when the nanoresonator is fixed at both ends changes, the final resonance frequency changes, and the tuning of the nanoresonator is realized.

[0033] Figure 4 The resonance frequencies of the (5,5) CNT and the CNT(5,5)@BNNT(17,0) nanoresonator under the axial electric field intensity of-10V / nm, -5V / nm, 0, 5V / nm and 10V / nm are shown.

[0034] As can be seen from the figure, in the absence of an external electric field, the resonance frequency of the (5,5) CNT nanoresonator is 198GHz, and the resonance frequency of the CNT(5,5)@BNNT(17,0) nanoresonator is 252.7GHz, which is much higher than the former.

[0035] On the other hand, under the action of the axial electric field, there is a certain difference in the change of the resonance frequencies of the two nanoresonators. Specifically, when the axial electric field intensity changes from-10V / nm to 10V / nm, the resonance frequency of the CNT(5,5)@BNNT(17,0) nanoresonator basically increases linearly, and the increment is 33GHz. In contrast, the resonance frequency of the (5,5) CNT nanoresonator is not affected by the axial electric field and remains 198GHz.

[0036] From the above results, it can be seen that the CNT(5,5)@BNNT(17,0) nanoresonator designed by the present application has significant piezoelectric tuning characteristics, and can solve the problem of difficult tuning of carbon nanotubes. In addition, compared with the (5,5) CNT nanoresonator, the CNT(5,5)@BNNT(17,0) nanoresonator has better resonance characteristics.

[0037] The above specific embodiments are only for illustrating the technical concept and structural features of the present application, and the purpose is to enable relevant persons skilled in the art to implement it, but the above content does not limit the protection scope of the present application, and any equivalent changes or modifications made according to the spirit and essence of the present application shall fall within the protection scope of the present application.

Claims

1. Resonator based on boron nitride carbon nanotube heterostructure, characterized in that: Includes boron nitride nanotubes and carbon nanotubes disposed within the boron nitride nanotubes; The boron nitride nanotubes are (17,0) BNNTs, and the carbon nanotubes are (5,5) CNTs; The boron nitride nanotubes and the carbon nanotubes form a double-layer coaxial heterostructure, and the boron nitride nanotubes and the carbon nanotubes have the same length and coincide in centroid. The boron nitride nanotubes are serrated, and the carbon nanotubes are armchair shaped. The boron nitride nanotubes are 10 nm long, and the difference between the inner and outer radii of the boron nitride nanotubes and the carbon nanotubes is 3.4 Å, with a fluctuation of no more than 0.1 Å; the boron nitride nanotubes and the carbon nanotubes are defect-free nanotubes. The nanoresonator has a fixed structure at both ends; and an axial electric field is applied to both ends of the boron nitride nanotube, causing the nitrogen and boron atoms in the outer boron nitride nanotube to undergo axial mechanical deformation under the action of the electric field force. The axial mechanical deformation causes the ratio of the axial load of the nanoresonator to the critical buckling load when both ends are fixed to change, thereby changing the resonance frequency of the nanoresonator and achieving tuning of the resonance frequency of the nanoresonator.

2. Resonator tuning method based on boron nitride carbon nanotube heterostructure, characterized in that Based on the resonator with the heterostructure of boron nitride carbon nanotubes as described in claim 1, the intensity of the axial electric field at both ends of the boron nitride carbon nanotubes is adjusted to change the resonant frequency and achieve tuning.

3. The method of tuning a resonator based on a boron nitride carbon nanotube heterostructure according to claim 2, wherein: The calculation of the resonant frequency of the nanoresonator includes the following steps: S1. Apply an axial electric field to both ends of the resonator, and apply an initial displacement of a certain length along the y-axis to the inner and outer layers of atoms near the centroid of the resonator. S2. Release the initial displacement constraint and allow the nanoresonator to oscillate freely for 500 ps to obtain the resonant frequency of the nanoresonator.

4. The method of tuning a resonator based on a boron nitride carbon nanotube heterostructure according to claim 3, wherein: After releasing the initial displacement constraint and allowing the nanoresonator to oscillate freely for 500 ps, ​​a fast Fourier transform is performed on the displacement of the resonator's centroid along the y-axis to obtain the frequency domain variation spectrum of the resonator's centroid, thus obtaining the resonant frequency of the nanoresonator.

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