JP2023006033A - Infrared sensor - Google Patents

Abstract

To provide an infrared sensor that can attain a high optical absorption efficiency and a high thermoelectric conversion efficiency.SOLUTION: The infrared sensor includes: a first graphene layer for absorbing infrared rays by using plasmon resonance; a second graphene layer having a connection unit connected to the first graphene layer; a first electrode and a second electrode connected to the second graphene layer, with the connection unit in between; and a control electrode for controlling the distribution of Fermi energy of the second graphene layer between the first and second electrodes, asymmetrically.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to infrared sensors.

Materials emit thermal radiation according to their temperature. The wavelength of thermal radiation from a substance at about room temperature has the highest intensity in the infrared wavelength band. For this reason, infrared sensors that detect thermal radiation are widely used for night vision, thermography, and the like.

In recent years, a method of infrared detection using graphene has been proposed. Graphene is a two-dimensional material in which carbon atoms are arranged in a two-dimensional honeycomb. Since graphene has a characteristic energy band structure, it can absorb light in a wide wavelength range from the ultraviolet region to the terahertz band.

As an example of an infrared sensor using graphene, a detection method using the photothermoelectric effect of graphene has been proposed. The photothermoelectric effect is a thermoelectric effect caused by heating accompanying light absorption. In this detection method, when light enters the graphene constituting the infrared sensor, electrons in the graphene absorb the light and obtain energy. The energy obtained by electrons through light absorption is shared by other electrons due to inter-electron scattering and thermalized. There is a difference between the time it takes for energy to be thermalized between electrons and the time it takes for energy sharing with lattice atoms, and the thermalization between electrons is faster, so the electron temperature is higher than the lattice temperature after light absorption is realized. At the metal electrode connected to the edge of graphene, the electron temperature is similar to the lattice temperature, so thermal diffusion forms an electron temperature distribution in the graphene.

In addition, a potential distribution can be formed in the graphene by applying different gate voltages in the plane. Since the Seebeck coefficient varies with the potential of graphene, the potential distribution within the graphene layer forms the Seebeck coefficient distribution. When the electron temperature distribution and the Seebeck coefficient distribution exist simultaneously, an electromotive force is formed by the Seebeck effect.

The light absorption efficiency in graphene is typically on the order of a few percent, which is small compared to common materials used for optical sensors. In recent years, a method for improving the light absorption efficiency of graphene by using plasmon resonance has been proposed.

WO2018/173347 JP 2018-37617 A

K. Kinoshita et al., Photo-thermoelectric detection of cyclotron resonance in asymmetrically carrier-doped graphene two-terminal device, Applied Physics Letter 113, 103102 (2018) X. Cai et al., Sensitive room-temperature terahertz detection via the photothermoelectric effect in graphene, Nature Nanotechnology 9, 814 (2014) A. Safaei et al., Dynamically tunable extraordinary light absorption in monolayer graphene, Physical Review B 96, 165431 (2017) A. Safaei et al., Dirac plasmon-assisted asymmetric hot carrier generation for room-temperature infrared detection, Nature Communications 10, 3498 (2019)

However, if the potential distribution of graphene is controlled to obtain good thermoelectric conversion efficiency, the effect of plasmon resonance is reduced. Conversely, if an attempt is made to enhance the effect of plasmon resonance, the thermoelectric conversion efficiency will decrease. In other words, the conventional infrared sensor cannot obtain good thermoelectric conversion efficiency while obtaining high light absorption efficiency due to plasmon resonance.

An object of the present disclosure is to provide an infrared sensor capable of achieving both high light absorption efficiency and high thermoelectric conversion efficiency.

According to one aspect of the present disclosure, a first graphene layer that absorbs infrared rays using plasmon resonance, a second graphene layer having a connecting portion connected to the first graphene layer, and the connecting portion sandwiched therebetween a first electrode and a second electrode connected to the second graphene layer; and a control electrode for asymmetrically controlling Fermi energy distribution of the second graphene layer between the first electrode and the second electrode. and an infrared sensor.

According to the present disclosure, both high light absorption efficiency and high thermoelectric conversion efficiency can be achieved.

1 is a plan view showing an infrared sensor according to a first embodiment; FIG. 1 is a cross-sectional view (part 1) showing an infrared sensor according to a first embodiment; FIG. FIG. 2 is a cross-sectional view (part 2) showing the infrared sensor according to the first embodiment; It is a figure which shows the relationship between the Fermi energy of graphene and a Seebeck coefficient. It is a top view which shows the infrared sensor which concerns on 2nd Embodiment. It is a sectional view showing an infrared sensor concerning a 2nd embodiment. FIG. 10 is a diagram showing an example of current paths in the infrared sensor according to the second embodiment; FIG. 10 is a diagram showing another example of current paths in the infrared sensor according to the second embodiment; It is a top view which shows the infrared sensor which concerns on 3rd Embodiment. FIG. 11 is a diagram showing an example of current paths in an infrared sensor according to a third embodiment; It is a top view which shows the infrared sensor which concerns on 4th Embodiment. FIG. 11 is a diagram showing an example of current paths in an infrared sensor according to a fourth embodiment; It is a sectional view showing an infrared sensor concerning a 5th embodiment.

Embodiments of the present disclosure will be specifically described below with reference to the accompanying drawings. In the present specification and drawings, constituent elements having substantially the same functional configuration may be denoted by the same reference numerals, thereby omitting redundant description. In this specification and drawings, the X1-X2 direction, the Y1-Y2 direction, and the Z1-Z2 direction are mutually orthogonal directions. A plane including the X1-X2 direction and the Y1-Y2 direction is the XY plane, a plane including the Y1-Y2 direction and the Z1-Z2 direction is the YZ plane, and a plane including the Z1-Z2 direction and the X1-X2 direction is the ZX plane. do. For convenience, the Z1 direction is defined as the upward direction, and the Z2 direction is defined as the downward direction. In addition, in the present disclosure, planar viewing means viewing an object from the Z1 side.

(First embodiment)
First, the first embodiment will be described. The first embodiment relates to an infrared sensor using graphene. FIG. 1 is a plan view showing an infrared sensor according to the first embodiment. FIG. 2 and 3 are cross-sectional views showing the infrared sensor according to the first embodiment. FIG. 2 corresponds to a cross-sectional view taken along line II-II in FIG. FIG. 3 corresponds to a cross-sectional view taken along line III-III in FIG.

As shown in FIGS. 1 to 3, the infrared sensor 1 according to the first embodiment mainly includes a substrate 11, an insulating layer 12, an insulating layer 13, a graphene layer 20, a control electrode 40, and a first electrode. 31 , a second electrode 32 and a fifth electrode 55 .

The substrate 11 has an insulating surface on the Z1 side. The substrate 11 may be, for example, an insulating substrate or a Si substrate with a thermal oxide film. A control electrode 40 is provided on the substrate 11 . Control electrode 40 includes a third electrode 43 and a fourth electrode 44 . The third electrode 43 and the fourth electrode 44 are electrically isolated from each other. The third electrode 43 and the fourth electrode 44 extend parallel to the X1-X2 direction. The fourth electrode 44 is arranged on the Y1 side of the third electrode 43 , and the third electrode 43 is arranged on the Y2 side of the fourth electrode 44 . An insulating layer 12 is provided on the substrate 11 so as to cover the third electrode 43 and the fourth electrode 44 . The insulating layer 12 is, for example, a silicon oxide layer.

A graphene layer 20 is provided on the insulating layer 12 . The graphene layer 20 includes one or multiple graphenes stacked together. When the graphene layer 20 contains a plurality of graphenes, the plurality of graphenes are preferably randomly (rotationally) laminated. This is because random (rotational) stacking provides relatively high carrier mobility. Graphene layer 20 includes a first graphene layer 21 and a second graphene layer 22 . The first graphene layer 21 and the second graphene layer 22 are connected to each other. The first graphene layer 21 functions as a light absorption region, and the second graphene layer 22 functions as a thermoelectric conversion region.

The second graphene layer 22 is arranged above the third electrode 43 and the fourth electrode 44 and overlaps the third electrode 43 and the fourth electrode 44 in plan view. Although details will be described later, the Fermi energy of the second graphene layer 22 is controlled by the third electrode 43 and the fourth electrode 44 . The first graphene layer 21 is arranged on the X2 side of the second graphene layer 22 , and the second graphene layer 22 is arranged on the X1 side of the first graphene layer 21 . In plan view, the first graphene layer 21 and the second graphene layer 22 have rectangular shapes. The dimension of the first graphene layer 21 in the Y1-Y2 direction is smaller than the dimension of the second graphene layer 22 in the Y1-Y2 direction. Of the two sides parallel to the X1-X2 direction of the first graphene layer 21, the side located on the Y1 side is closer to the Y1 side than the two sides of the second graphene layer 22 parallel to the X1-X2 direction. It is on the Y2 side. Among the two sides parallel to the X1-X2 direction of the first graphene layer 21, the side located on the Y2 side is closer to the Y2 side than the two sides parallel to the X1-X2 direction of the second graphene layer 22. It is on the Y1 side. The second graphene layer 22 has a connecting portion 22A that continues to the first graphene layer 21 . For example, the connecting portion 22A overlaps the third electrode 43 and the fourth electrode 44 in plan view.

The first graphene layer 21 absorbs infrared rays using plasmon resonance. For example, a plurality of openings 23 are periodically formed in the first graphene layer 21 . For example, the planar shape of the openings 23 is circular with a diameter of 400 nm, and the plurality of openings 23 are arranged in a regular hexagonal lattice with a pitch of 600 nm. On the other hand, openings 23 are not formed in the second graphene layer 22 . The second graphene layer 22 may also absorb infrared rays, but the density of carriers photoexcited by absorption of infrared rays in the second graphene layer 22 is higher than the density of carriers photoexcited by absorption of infrared rays in the first graphene layer 21. low.

An insulating layer 13 is provided on the insulating layer 12 so as to cover the graphene layer 20 . The insulating layer 13 is, for example, an aluminum oxide layer with a thickness of about 10 nm. The insulating layer 13 is formed with an opening 13A exposing the Y2 side end of the second graphene layer 22 and an opening 13B exposing the Y1 side end of the second graphene layer 22 . A first electrode 31 is provided inside the opening 13A. The first electrode 31 contacts the second graphene layer 22 . A second electrode 32 is provided inside the opening 13B. The second electrode 32 contacts the second graphene layer 22 . In plan view, the third electrode 43 and the fourth electrode 44 are arranged between the first electrode 31 and the second electrode 32, and the third electrode 43 is arranged between the first electrode 31 and the fourth electrode 44. , the fourth electrode 44 is arranged between the second electrode 32 and the third electrode 43 . The first electrode 31 and the second electrode 32 are connected to the second graphene layer 22 with the connecting portion 22A interposed therebetween. Materials for the first electrode 31 and the second electrode 32 are not particularly limited, and Au, Pd, Ni, Cr, or Ti may be used, for example. The 1st electrode 31 and the 2nd electrode 32 may contain the laminated body of these metals. For example, the first electrode 31 and the second electrode 32 may include a laminate of a Ti film and an Au film formed on the Ti film, or a Cr film and an Au film formed on the Cr film. may include a laminate of The material may be common between the first electrode 31 and the second electrode 32, or may be different.

For example, with respect to the center line C between the first electrode 31 and the second electrode 32 of the second graphene layer 22, the third electrode 43 is arranged on the first electrode 31 side, that is, the Y2 side, and the fourth electrode 44 is arranged on the second electrode 32 side, that is, on the Y1 side.

A fifth electrode 55 is provided on the insulating layer 13 . The fifth electrode 55 is made of a material that transmits infrared rays. The fifth electrode 55 is a transparent conductive film such as an indium tin oxide (ITO) film. The fifth electrode 55 is arranged above the first graphene layer 21 and overlaps the first graphene layer 21 in plan view. Although details will be described later, the Fermi energy of the first graphene layer 21 is controlled by the fifth electrode 55 .

Here, the operation of the infrared sensor 1 according to the first embodiment will be described.

The fifth electrode 55 controls the Fermi energy of the first graphene layer 21 to a range in which light absorption due to plasmon resonance is likely to occur in the first graphene layer 21 . For example, the Fermi energy of the first graphene layer 21 is controlled to about +0.5 eV to +1.0 eV.

In addition, the Fermi energy of the second graphene layer 22 is controlled by the third electrode 43 and the fourth electrode 44 to a range in which the electromotive force due to the Seebeck effect in the second graphene layer 22 tends to increase. FIG. 4 is a diagram showing the relationship between the Fermi energy of graphene and the Seebeck coefficient. As shown in FIG. 4, the Seebeck coefficient of graphene becomes maximum when the Fermi energy is about 0.05 eV, and becomes minimum when the Fermi energy is about −0.05 eV. Therefore, for example, the Fermi energy of the portion of the second graphene layer 22 that overlaps with the third electrode 43 is controlled to about +0.05 eV or -0.05 eV, and the Fermi energy of the portion that overlaps with the fourth electrode 44 has the opposite polarity. is controlled to about −0.05 eV or about +0.05 eV.

Note that the Seebeck coefficient S of graphene can be expressed by the following Mott approximation formula (formula (1)) and a phenomenological formula (formula (2)) for the electrical conductivity σ of graphene. In equations (1) and (2), e is the elementary charge, k _B is the Boltzmann constant, T is the absolute temperature, ε _F is the Fermi energy, and σ _min and Δ are phenomenological parameters. is.

According to equations (1) and (2), the absolute value of the Seebeck coefficient S of graphene has a maximum value at ε _F =±Δ, and monotonically decreases with respect to the Fermi energy in the region where the Fermi energy is larger than that. becomes. The relationships shown in FIG. 4 are thus derived. As shown in FIG. 4, if the value of the phenomenological parameter Δ is 100 meV as a typical value, the Seebeck coefficient S of graphene reaches the maximum value at the Fermi energy of about 0.5 eV to 1.0 eV, which is suitable for plasmon resonance. The value is about 1/4 to 1/2.

Infrared rays incident on the infrared sensor 1 pass through the fifth electrode 55 and are absorbed by the first graphene layer 21 (light absorption region). At this time, since the Fermi energy of the first graphene layer 21 is controlled within a range in which light absorption due to plasmon resonance is likely to occur, carriers in the first graphene layer 21 are heated with high efficiency. Carriers heated to a high temperature flow out to the second graphene layer 22 (thermoelectric conversion region) adjacent to the first graphene layer 21 by thermal diffusion.

Since the Fermi energy of the second graphene layer 22 is controlled within a range in which the electromotive force due to the Seebeck effect tends to increase, the carriers that have flowed into the second graphene layer 22 are further thermally diffused into the third electrode 43 and the fourth electrode 44 . flows to the first electrode 31 or the second electrode 32 depending on the polarity of the voltage. In this way, an infrared responsive output is formed.

As described above, the Fermi energy range in which light absorption due to plasmon resonance tends to occur differs from the Fermi energy range in which the electromotive force due to the Seebeck effect tends to increase. In this embodiment, the Fermi energy of the first graphene layer 21 and the Fermi energy of the second graphene layer 22 can be individually controlled. Therefore, high light absorption efficiency can be obtained in the first graphene layer 21 functioning as a light absorption region, and high thermoelectric conversion efficiency can be obtained in the second graphene layer 22 functioning as a thermoelectric conversion region. Therefore, according to this embodiment, both high light absorption efficiency and high thermoelectric conversion efficiency can be achieved.

The distance between the fifth electrode 55 and the first graphene layer 21 is preferably smaller than the distance between the control electrode 40 (the third electrode 43 and the fourth electrode 44) and the second graphene layer 22. . This is to make it easier to apply a voltage from the fifth electrode 55 to the first graphene layer 21 whose absolute value is higher than the absolute value of the voltage applied from the control electrode 40 to the second graphene layer 22 .

(Second embodiment)
Next, a second embodiment will be described. FIG. 5 is a top view showing an infrared sensor according to the second embodiment. FIG. 6 is a cross-sectional view showing an infrared sensor according to the second embodiment.
FIG. 6 corresponds to a cross-sectional view taken along line VI-VI in FIG.

In the infrared sensor 2 according to the second embodiment, as shown in FIGS. 5 and 6, an opening 13C is formed in the insulating layer 13 to expose the Y2-side end of the first graphene layer 21 . A sixth electrode 56 is provided inside the opening 13C. The sixth electrode 56 contacts the first graphene layer 21 . The material of the sixth electrode 56 is, for example, the same as the material of the first electrode 31 and the second electrode 32 . And the 1st electrode 31 and the 6th electrode 56 are electrically connected.

Other configurations are the same as those of the first embodiment.

In the infrared sensor 2 according to the second embodiment, the polarity of the voltage of the fifth electrode 55 and the polarity of the voltage of the third electrode 43 are the same, and the polarity of the voltage of the fourth electrode 44 is opposite. For example, the polarity of the voltage of the fifth electrode 55 and the voltage of the third electrode 43 is assumed to be positive, and the polarity of the voltage of the fourth electrode 44 is assumed to be negative. Conversely, the polarity of the voltage of the fifth electrode 55 and the voltage of the third electrode 43 may be negative, and the polarity of the voltage of the fourth electrode 44 may be positive.

When the polarity of the voltage of the fifth electrode 55 and the voltage of the third electrode 43 is positive, and the polarity of the voltage of the fourth electrode 44 is negative, the conductivity type of the first graphene layer 21 is n-type, and the second graphene layer. The conductivity type of the portion closer to the first electrode 31 than the center line C of 22 is n-type, and the conductivity type of the portion closer to the second electrode 32 is p-type. In this case, electrons are heated as carriers in the first graphene layer 21, current flows according to the thermal diffusion of the electrons, and an infrared responsive output is formed.

Further, when the polarities of the voltage of the fifth electrode 55 and the voltage of the third electrode 43 are negative, and the polarity of the voltage of the fourth electrode 44 is positive, the conductivity type of the first graphene layer 21 becomes p-type, and the conductivity type of the second graphene layer 21 becomes p-type. The conductivity type of the portion closer to the first electrode 31 than the center line C of the graphene layer 22 is p-type, and the conductivity type of the portion closer to the second electrode 32 is n-type. In this case, holes are heated as carriers in the first graphene layer 21, current flows according to the thermal diffusion of the holes, and an infrared responsive output is formed.

In the first embodiment, when infrared rays are intermittently irradiated, carriers that have moved from the first graphene layer 21 to the second graphene layer 22 while the infrared rays are on are , the first graphene layer 21 can be returned to. On the other hand, when infrared rays are continuously irradiated, carriers continue to move from the first graphene layer 21 to the second graphene layer 22, so carriers accumulate in the second graphene layer 22, An electric field is generated between the graphene layer 21 and the second graphene layer 22 in a direction that hinders movement of carriers. The occurrence of such an electric field may reduce sensitivity.

In the second embodiment, carriers that have moved from the first graphene layer 21 to the second graphene layer 22 move to the first graphene layer 21 through the first electrode 31 and the sixth electrode 56 . Therefore, accumulation of carriers in the second graphene layer 22 is suppressed, and good sensitivity can be maintained even when infrared rays are continuously irradiated.

When the polarity of the voltage of the fifth electrode 55 and the voltage of the third electrode 43 is positive, and the polarity of the voltage of the fourth electrode 44 is negative, outside the graphene layer 20, as shown in FIG. A current I1 flows from 56 toward the first electrode 31 . When the polarity of the voltage of the fifth electrode 55 and the voltage of the third electrode 43 is negative, and the polarity of the voltage of the fourth electrode 44 is positive, outside the graphene layer 20, as shown in FIG. A current I2 flows from 31 toward the sixth electrode 56 .

(Third Embodiment)
Next, a third embodiment will be described. FIG. 9 is a top view showing an infrared sensor according to the third embodiment.

In the infrared sensor 3 according to the third embodiment, a DC power source 61 is connected between the first electrode 31 and the sixth electrode 56, as shown in FIG. A positive electrode of the DC power supply 61 is connected to the first electrode 31 and a negative electrode is connected to the sixth electrode 56 .

Other configurations are the same as those of the second embodiment.

In the infrared sensor 2 according to the second embodiment, the voltage polarity of the fifth electrode 55 is negative. If the polarities of the voltages of the third electrode 43 and the fourth electrode 44 are different from each other, either may be positive. When the voltage polarity of the fifth electrode 55 is positive, the conductivity type of the first graphene layer 21 is n-type. Further, when the polarity of the voltage of the third electrode 43 is positive and the polarity of the voltage of the third electrode 43 is negative, the conductivity type of the portion on the first electrode 31 side of the center line C of the second graphene layer 22 is It becomes n-type, and the conductivity type of the portion on the second electrode 32 side becomes p-type. On the other hand, when the voltage polarity of the third electrode 43 is negative and the voltage polarity of the third electrode 43 is positive, the conductivity type of the portion of the second graphene layer 22 closer to the first electrode 31 than the center line C is It becomes p-type, and the conductivity type of the portion on the second electrode 32 side becomes n-type.

If the polarity of the voltage of the fifth electrode 55 is negative and the polarities of the voltages of the third electrode 43 and the fourth electrode 44 are different from each other, as shown in FIG. A current I3 flows from the sixth electrode 56 toward the first electrode 31 through the .

Effects similar to those of the second embodiment can be obtained by the third embodiment. Further, in the third embodiment, the diffusion of carriers is further promoted by the DC power supply 61 .

(Fourth embodiment)
Next, a fourth embodiment will be described. FIG. 11 is a top view showing an infrared sensor according to the fourth embodiment.

In the infrared sensor 4 according to the fourth embodiment, a DC power supply 62 is connected between the first electrode 31 and the sixth electrode 56, as shown in FIG. A positive electrode of the DC power supply 62 is connected to the sixth electrode 56 and a negative electrode is connected to the first electrode 31 .

Other configurations are the same as those of the second embodiment.

In the infrared sensor 2 according to the second embodiment, the voltage polarity of the fifth electrode 55 is positive. If the polarities of the voltages of the third electrode 43 and the fourth electrode 44 are different from each other, either may be positive. When the polarity of the voltage applied to the fifth electrode 55 is negative, the conductivity type of the first graphene layer 21 is p-type. Further, when the polarity of the voltage of the third electrode 43 is positive and the polarity of the voltage of the third electrode 43 is negative, the conductivity type of the portion on the first electrode 31 side of the center line C of the second graphene layer 22 is It becomes n-type, and the conductivity type of the portion on the second electrode 32 side becomes p-type. On the other hand, when the voltage polarity of the third electrode 43 is negative and the voltage polarity of the third electrode 43 is positive, the conductivity type of the portion of the second graphene layer 22 closer to the first electrode 31 than the center line C is It becomes p-type, and the conductivity type of the portion on the second electrode 32 side becomes n-type.

If the voltage polarity of the fifth electrode 55 is positive and the voltage polarities of the third electrode 43 and the fourth electrode 44 are different from each other, as shown in FIG. A current I4 flows from the first electrode 31 to the sixth electrode 56 via the .

Effects similar to those of the second embodiment can be obtained by the fourth embodiment as well. Further, in the fourth embodiment, the diffusion of carriers is further promoted by the DC power supply 62 .

(Fifth embodiment)
Next, a fifth embodiment will be described. FIG. 13 is a cross-sectional view showing an infrared sensor according to the fifth embodiment. FIG. 13, like FIG. 2, corresponds to a cross-sectional view taken along line II-II in FIG.

The infrared sensor 5 according to the fifth embodiment has a reflective layer 57 that reflects the infrared rays transmitted through the first graphene layer 21 toward the first graphene layer 21, as shown in FIG. The reflective layer 57 is provided, for example, on the substrate 11 and is followed by the insulating layer 12 . The reflective layer 57 overlaps the first graphene layer 21 in plan view. The reflective layer 57 is, for example, an Au layer.

Other configurations are the same as those of the first embodiment.

Effects similar to those of the first embodiment can also be obtained by the fifth embodiment. Furthermore, since the infrared rays reflected by the reflective layer 57 are incident on the first graphene layer 21, the sensitivity can be improved.

A reflective layer 57 may be provided in the second to fourth embodiments as in the fifth embodiment.

Although the preferred embodiments and the like have been described in detail above, the present invention is not limited to the above-described embodiments and the like, and various modifications can be made to the above-described embodiments and the like without departing from the scope of the claims. Modifications and substitutions can be made.

Hereinafter, various aspects of the present disclosure will be collectively described as appendices.

(Appendix 1)
a first graphene layer that absorbs infrared rays using plasmon resonance;
a second graphene layer having a connecting portion connected to the first graphene layer;
a first electrode and a second electrode connected to the second graphene layer with the connecting portion interposed therebetween;
a control electrode that asymmetrically controls the Fermi energy distribution of the second graphene layer between the first electrode and the second electrode;
An infrared sensor characterized by comprising:
(Appendix 2)
The control electrode is
a third electrode disposed between the first electrode and the second electrode in plan view;
a fourth electrode disposed between the third electrode and the second electrode in plan view;
The infrared sensor according to appendix 1, characterized by comprising:
(Appendix 3)
Based on the center line between the first electrode and the second electrode of the second graphene layer,
The third electrode is arranged on the first electrode side,
The infrared sensor according to appendix 2, wherein the fourth electrode is arranged on the second electrode side.
(Appendix 4)
4. The infrared sensor according to any one of Appendices 1 to 3, further comprising a fifth electrode that controls the Fermi energy of the first graphene layer.
(Appendix 5)
5. The infrared sensor according to claim 4, wherein the distance between the fifth electrode and the first graphene layer is smaller than the distance between the control electrode and the second graphene layer.
(Appendix 6)
a sixth electrode connected to the first graphene layer;
6. The infrared sensor according to any one of appendices 1 to 5, wherein the first electrode and the sixth electrode are electrically connected.
(Appendix 7)
a sixth electrode connected to the first graphene layer;
a DC power supply electrically connected between the first electrode and the sixth electrode;
The infrared sensor according to any one of appendices 1 to 5, characterized by comprising:
(Appendix 8)
8. The infrared sensor according to any one of Appendices 1 to 7, wherein a plurality of openings are periodically formed in the first graphene layer.
(Appendix 9)
9. The infrared sensor according to any one of Appendices 1 to 8, further comprising a reflective layer that reflects infrared rays transmitted through the first graphene layer toward the first graphene layer.

1, 2, 3, 4, 5: infrared sensor 21: first graphene layer 22: second graphene layer 22A: connecting portion 31: first electrode 32: second electrode 40: control electrode 43: third electrode 44: third 4 electrodes 55: fifth electrode 56: sixth electrode 57: reflective layer 61, 62: DC power supply

Claims (6)

a first graphene layer that absorbs infrared rays using plasmon resonance;
a second graphene layer having a connecting portion connected to the first graphene layer;
a first electrode and a second electrode connected to the second graphene layer with the connecting portion interposed therebetween;
a control electrode that asymmetrically controls the Fermi energy distribution of the second graphene layer between the first electrode and the second electrode;
An infrared sensor characterized by comprising: The control electrode is
a third electrode disposed between the first electrode and the second electrode in plan view;
a fourth electrode disposed between the third electrode and the second electrode in plan view;
The infrared sensor according to claim 1, characterized by comprising: 3. The infrared sensor according to claim 1, further comprising a fifth electrode for controlling the Fermi energy of said first graphene layer. a sixth electrode connected to the first graphene layer;
4. The infrared sensor according to claim 1, wherein said first electrode and said sixth electrode are electrically connected. a sixth electrode connected to the first graphene layer;
a DC power supply electrically connected between the first electrode and the sixth electrode;
4. The infrared sensor according to any one of claims 1 to 3, characterized by comprising: The infrared sensor according to any one of claims 1 to 5, wherein a plurality of openings are periodically formed in the first graphene layer.

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