CN213209315U

CN213209315U - Graphene stress optical sensor based on plasmon resonance

Info

Publication number: CN213209315U
Application number: CN202020890173.6U
Authority: CN
Inventors: 马增红; 陈子坚; 徐建; 张链; 陈霞; 刘晔
Original assignee: Tianjin Well Line Electric Equipment Co ltd; Tianjin Sino German University of Applied Sciences
Current assignee: Tianjin Well Line Electric Equipment Co ltd; Tianjin Sino German University of Applied Sciences
Priority date: 2020-05-25
Filing date: 2020-05-25
Publication date: 2021-05-14
Anticipated expiration: 2030-05-25

Abstract

The utility model relates to an optical sensor technical field especially relates to a graphite alkene stress optical sensor based on plasmon resonance, including periodic graphite alkene nanobelt array and substrate, periodic graphite alkene nanobelt array is arranged in on the substrate. The graphene plasmons have very strong spatial locality and field enhancement effect, can realize high quality factors, and are very favorable for the realization of nano photonics devices based on the graphene plasmons in integrated photonics.

Description

Graphene stress optical sensor based on plasmon resonance

Technical Field

The utility model relates to an optical sensor technical field especially relates to a graphite alkene stress optical sensor based on plasmon resonance.

Background

Besides excellent light transmission and good electrical conductivity, graphene also has excellent mechanical properties, for example, the tensile strength of graphene is 125GPa, the young modulus is 1TPa, and the material with the highest strength is known at present. At present, stress sensors based on graphene are widely concerned by researchers. Compared with a silicon stress sensor, the graphene stress sensor has the characteristics of higher sensitivity, lower energy consumption, easiness in integration, easiness in realization of intellectualization, nanoscale size and the like. This means that graphene pressure sensors can be used in many more applications. Such as in the biomedical field, may be used to detect blood pressure or tissue pressure inside a human body, wearable electronics, robotic "skin", etc. In recent years, graphene stress sensors with different mechanisms have been studied intensively, including piezoresistive graphene stress sensors, capacitive strain sensors, fiber-optic graphene stress sensors, optical sensors based on raman spectrum enhancement, and the like. Piezoresistive sensors based on graphene have been extensively studied due to the relatively simple electrical system. But resistive graphene strain sensors are susceptible to electromagnetic interference from nearby instruments and charged objects. On the other hand, obtaining high sensitivity often requires applying a large stress, which is difficult to obtain in practice. In addition, too much pressure may also cause deformation of the unrecoverable graphene, greatly limiting the application of graphene strain sensors. Therefore, a new approach for realizing highly sensitive strain sensing by probing without destroying the graphene lattice structure is needed.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to overcome the not enough of above-mentioned technique, and provide a graphite alkene stress optical sensor based on plasmon resonance.

The utility model discloses a realize above-mentioned purpose, adopt following technical scheme: the utility model provides a graphite alkene stress optical sensor based on plasmon resonance which characterized in that: the graphene nanoribbon array structure comprises a periodic graphene nanoribbon array and a substrate, wherein the periodic graphene nanoribbon array is arranged on the substrate.

Preferably, the periodic graphene nanoribbon array is single-layer graphene grown by CVD or mechanically exfoliated.

Preferably, the substrate is a flexible base PDMS or PET to achieve dynamic stretching of graphene.

Preferably, when tensile force is applied to the graphene nanoribbon array, the graphene plasmon resonance peak position can obviously move, and the Fourier infrared spectrometer is used for detecting the movement of the peak position to realize the detection of graphene stress.

The utility model has the beneficial effects that 1, the graphene is used as a novel material, is environment-friendly and rich in source, and can realize cheap large-scale production, thereby effectively reducing the cost. 2. The graphene plasmons have very strong spatial locality and field enhancement effect, can realize high quality factors, and are very favorable for the realization of nano photonics devices based on the graphene plasmons in integrated photonics. 3. The utility model discloses the configuration is simple, easily processes and tensile to for being applied to nanometer photoelectronic device design and integrated sub-wavelength stress sensing device that provides the ideal.

Drawings

Fig. 1 is a schematic structural diagram of a graphene nanoribbon array according to an embodiment of the present invention;

fig. 2 shows the plasmon resonance positions of graphene under the action of the pulling forces at different angles according to the embodiment of the present invention;

3 a-3 d are graphs showing the relative movement of the plasmon resonance position with the fermi level and the nanobelt width under different strain moduli k and directions according to the embodiment of the present invention;

FIG. 4 shows the relative shift of the resonance frequency with different strain moduli k and different pull directions in an embodiment of the present invention;

fig. 5a and 5b are sensitivity and quality factors for embodiments of the present invention;

fig. 6a and 6b show the plasmon resonance position change of the embodiment of the present invention on PDMS.

Detailed Description

Spatially relative terms such as "above … …", "above … …", "above … …", "above", and the like, may be used herein for ease of description to describe the spatial relationship of one feature or characteristic to another feature or characteristic as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, devices described as "above" or "on" other devices or configurations would then be oriented "below" or "under" the other devices or configurations. Thus, the exemplary term "above … …" can include both an orientation of "above … …" and "below … …". The device may be otherwise variously oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

As shown in fig. 1, due to the thickness of the monoatomic layer of graphene, the optical response of graphene can be effectively controlled by external stress. In the process of stretching the graphene, two carbon sublattices of the graphene deform, and the energy band structure of the graphene is regulated and controlled along with the change of the crystal lattices, so that the anisotropy of the optical conductivity of the graphene can be induced. For the doped graphene micro-nano structure, a local surface plasmon mode can be supported, and plasmon resonance is very sensitive to the change of the conductivity.

Based on the above, a graphene stress optical sensor based on plasmon resonance was designed for the first time, and the strain sensor is a typical optical sensor. A periodic array of graphene nanoribbons 1 is placed on a flexible substrate 2. When tension is applied to the configuration, the graphene plasmon resonance peak position can obviously move, and the detection of graphene stress can be realized by detecting the movement of the peak position by using a Fourier infrared spectrometer. Compared with other types of graphene stress sensors reported in documents, the graphene plasmon-based stress sensor is an optical sensor based on a graphene micro-nano structure, and is beneficial to design of an integrated photonic device on one hand, and on the other hand, a higher quality factor can be obtained through slight deformation on the premise of not damaging a lattice structure, so that efficient detection of strain is facilitated.

The graphene may be CVD grown or mechanically exfoliated single layer graphene. The substrate is a common flexible base PDMS or PET to achieve dynamic stretching of graphene.

The utility model discloses based on following two aspects principle: 1. when incident light irradiates on doped graphene with a micro-nano structure, the surface plasmon of the graphene can be excited at a specific resonance wavelength, the property of the excited surface plasmon of the graphene is related to the in-plane conductivity of the graphene, and the graphene can be regulated and controlled through a field effect or stress application, so that the resonance of the plasmon of the graphene can be effectively changed. 2. When tensile force is applied to graphene, the surface conductivity of the graphene can be changed in an anisotropic mode, the in-plane conductivity depends on the tensile force and the direction of the tensile force, and the resonance position of a plasmon of a graphene micro-nano structure can be effectively changed through the change of the conductivity. On the contrary, the size and the direction of the tensile force of the graphene plasmon can be effectively detected through the change of the plasmon resonance position of the graphene micro-nano structure.

The present invention will be further explained with reference to the drawings and examples.

In this embodiment, the width W of the graphene nanoribbon array is of nanometer order, the core goal of the present invention is stress sensing, without regard to coupling between nanoribbons, so the period L can be set to 10W. The substrate is a flexible substrate PDMS or PET that can be used for stretching.

Graphene conductivity under stress:

wherein theta represents an included angle between the tension direction and zigzag, and rho is 0.165, which is the Poisson's ratio of graphene

Wherein σ (ω) is a graphene conductivity formula using random phase approximation

Wherein the content of the first and second substances,

the temperature T was set to 300K and the thickness of the graphene was taken to be d-0.5 nm.

And (4) performing analog simulation by adopting a finite element method.

FIG. 2 shows that the width W of the graphene nanoribbon is 50nm, the Fermi level EF is 0.4eV, and the carrier mobility μ is 10000cm²and/Vs, assuming that the graphene is in isotropy when no tensile force acts, the transmission spectrum of the graphene nanoribbon array is shown as a solid line in the figure, and the resonance position is 52.9 THz. Under stretching (assuming a strain size k of 0.2), the transmission line shifts. When θ is 0 °, the resonance position is 33.2THz (dotted line), and the resonance line is red-shifted. When θ is 90 °, the resonance position is 59.6THz (dotted line), and the resonance line is blue-shifted.

3 a-3 d graphene plasmon resonance depends on the fermi level of graphene and the width W of a graphene nanoribbon, so that the change of the relative movement of the plasmon resonance position with the fermi level and the nanoribbon width under different tension sizes and directions is studied. Where the relative shift in resonant frequency may be expressed as Δ f ═ f (f-f)₀)/f₀X 100% where f₀For arrays of graphene nanoribbons without tensile forcesThe location of the resonance. Fig. 3a and 3b show the effect of different graphene fermi levels and applied tensile force on the relative shift of resonance frequency when the graphene nanoribbon width is 50 nm. When the Fermi level of the graphene is from 0.1eV to 0.8eV, the resonance frequency of the graphene nanoribbon array is hardly shifted under the same magnitude and direction of the tensile force. However, for different applied tensile forces, the resonance position shifts, red-shifted when θ is 0 ° for fig. 3a, and-38% for the relative shift Δ f when the maximum deformation amount is 0.2, blue-shifted when θ is 90 ° for fig. 3b, and 14% for the relative shift Δ f when the maximum deformation amount is 0.2.

Similarly, we have studied the effect of different nanobelt widths on the resonance position of the graphene nanobelt array, and also we can see from fig. 3c and fig. 3d that the change of the nanobelt width has no effect on the change of the resonance position of the graphene nanobelt array. Therefore, we can draw a conclusion that the utility model discloses the stress sensor based on graphite alkene plasmon resonance effect that the implementation case provided does not rely on factors such as graphite alkene fermi energy level, graphite alkene structure size.

FIG. 4: the relative shift of the resonance position of the graphene nanoribbon array varies with the strain modulus k and the pull direction, and it can be seen from the figure that when the pull direction varies from 0 ° to 90 °, the relative shift of the resonance frequency varies from-38% to 13% with the increase of the strain modulus k. The magnitude and direction of the stress can be detected by using the change of the relative position of the frequency, so that the stress sensing is realized.

Fig. 5a and 5b are sensitivity and quality factor of a stress sensor based on the graphene plasmon effect. The sensitivity is calculated as: s ═ f-f₀) ,/Δ κ, fig. 5a shows sensitivity, (a) sensitivity S when θ is 0 °_//＝3260.6cm^-1When theta is 90 degrees, the sensitivity S is 1109.1cm^-1In order to keep the technical parameters consistent with those of the mid-infrared Fourier spectrometer, the wave number is taken as a unit. The quality factor is an important parameter for measuring the sensor based on the localized surface plasmon resonance effect, and the calculation formula is as follows: FOM is S/FWHM, S isSensitivity, FWHM is full width at half maximum. The half-width of the localized plasmon is determined by loss, and for graphene, the half-width depends on the carrier mobility zero. Fig. 5b shows the variation of the quality factor FOM with the graphene carrier mobility. When the carrier mobility of the graphene is changed from 2000 to 10000cm²at/Vs, the quality factor increases from 50 to 320 for θ 0 and from 10 to 110 for θ 90. This shows that even though the mobility of graphene is not high in specific experiments and applications, we can obtain a higher quality factor, which is very beneficial to realize stress sensing.

Fig. 6a and 6b are for simplicity, both studies above consider the graphene suspended state. When considering a flexible substrate, taking PDMS as an example (fig. 6a is the dielectric constant of PDMS), it can be seen that the graphene stress sensing characteristics of the substrate are still maintained.

The utility model discloses a graphite alkene stress sensor based on local plasmon resonance effect, the utility model relates to a novel optical sensor has the advantage that structural configuration is simple and easily survey concurrently, will have very big application potentiality in nanometer photoelectric integrated circuit.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, a plurality of modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.

Claims

1. The utility model provides a graphite alkene stress optical sensor based on plasmon resonance which characterized in that: the graphene nanoribbon array structure comprises a periodic graphene nanoribbon array and a substrate, wherein the periodic graphene nanoribbon array is arranged on the substrate.

2. The plasmon resonance-based graphene stress optical sensor of claim 1, wherein: the periodic graphene nanoribbon array is single-layer graphene grown by CVD or mechanically exfoliated.

3. The plasmon resonance-based graphene stress optical sensor of claim 1, wherein: the substrate is a flexible substrate PDMS or PET so as to realize dynamic stretching of graphene.