Bolometer, infrared detection device, and infrared detection method

Abstract

To provide a bolometer, an infrared detection device, and an infrared detection method capable of easily achieving a high TCR.SOLUTION: The bolometer includes a gate electrode to which a gate voltage can be applied, a drain electrode to which a drain voltage can be applied, a source electrode, and a first film connecting the drain electrode and the source electrode and including a carbon nanotube, wherein the gate voltage is periodically swept between an upper limit value and a lower limit value.SELECTED DRAWING: Figure 12

Description

[Technical Field]

[0001] The present disclosure relates to a bolometer, an infrared detection device, and an infrared detection method. [Background technology]

[0002] It is known to use a bolometer as an infrared sensor.

[0003] For example, Patent Document 1 discloses a bolometer that uses a semiconducting carbon nanotube (CNT) to improve the temperature coefficient of resistance (TCR), which is related to the improvement of the infrared sensor. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-49207 Summary of the Invention [Problem to be solved by the invention]

[0005] The infrared receiving element disclosed in Patent Document 1 controls the position of the Fermi energy of the channel portion containing CNT by doping the channel portion with a control material containing an electrolyte. In addition, the infrared receiving element discloses that the position of the Fermi energy of the channel portion containing CNT can be further controlled by setting the voltage between the source electrode and the drain electrode and the voltage between the source electrode and the gate electrode, thereby controlling the TCR value. However, depending on the voltage value set, it may be difficult to achieve a high TCR.

[0006] An object of the present disclosure is to provide a bolometer, an infrared detection device, and an infrared detection method that solve the above-mentioned problems. [Means for solving the problem]

[0007] The bolometer of the present disclosure comprises a gate electrode to which a gate voltage can be applied, a drain electrode to which a drain voltage can be applied, a source electrode, and a first film connecting the drain electrode and the source electrode and containing carbon nanotubes, and the gate voltage is swept periodically between an upper limit value and a lower limit value.

[0008] The infrared detection method disclosed herein includes a step of applying a drain voltage to a drain electrode of a bolometer having a gate electrode, a drain electrode, a source electrode, and a first film connecting the drain electrode and the source electrode and containing carbon nanotubes, and a step of sweeping a gate voltage to the gate electrode while having a periodicity between an upper limit value and a lower limit value. [Effects of the Invention]

[0009] The bolometer, infrared detection device, and infrared detection method according to the present disclosure make it easy to achieve a high TCR. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a diagram illustrating an example of a configuration of an infrared detection device according to the present disclosure. [Figure 2] 1 is a cross-sectional view I showing an example of the configuration of a bolometer according to the present disclosure. [Figure 3] FIG. 1 illustrates an example transport characteristic of a bolometer according to the present disclosure. [Figure 4] FIG. 10 is a diagram showing an example of electrical characteristics calculated based on the transport characteristics of a bolometer according to the present disclosure. [Figure 5] FIG. 10 is a diagram showing an example of the relationship between the electrical characteristics of a bolometer according to the present disclosure and the drain voltage applied to the drain electrode. [Figure 6] 1 is a diagram I showing an example of the relationship between the electrical characteristics of a bolometer according to the present disclosure and the periodicity of the gate voltage applied to the gate electrode. [Figure 7]10A and 10B are diagrams illustrating exemplary waveforms for voltage values ​​when a bolometer according to the present disclosure is swept. [Figure 8] FIG. 2 is a diagram II showing an example of the relationship between the electrical characteristics of a bolometer according to the present disclosure and the periodicity of the gate voltage applied to the gate electrode. [Figure 9] 1 is a flowchart I showing an example of processing of an infrared detection method according to the present disclosure. [Figure 10] 10A and 10B are diagrams showing examples of waveforms for each voltage value when a bolometer according to a modified example is swept. [Figure 11] FIG. 10 is a cross-sectional view showing an example of the configuration of a bolometer according to a modified example. [Figure 12] 2 is a cross-sectional view II showing an example of the configuration of a bolometer according to the present disclosure. [Figure 13] 10 is a flowchart II showing an example of processing of an infrared detection method according to the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, examples of each embodiment according to the present disclosure will be described using the drawings. Note that the drawings and specific configurations used in each embodiment should not be used to interpret the disclosure. The same or corresponding configurations in all drawings will be assigned the same reference numerals, and common descriptions will be omitted. It should be noted that in this disclosure, the drawings may relate to one or more embodiments.

[0012] First Embodiment Hereinafter, an embodiment according to the present disclosure will be described with reference to the drawings. An example of the configuration of a bolometer according to the present disclosure will be described below with reference to FIGS.

[0013] (Configuration of infrared detection device) The infrared detecting device 100 is used to measure the drain current at a predetermined detection timing and detect infrared rays. As shown in FIG. 1, the infrared detection device 100 includes a bolometer 1 and a sweep unit 2. The sweep unit 2 periodically sweeps the gate voltage applied to the gate electrode included in the bolometer 1. The sweep unit 2 may be a sweep signal generator or other signal generator. The sweep unit 2 may also be a multivibrator or other oscillator circuit.

[0014] The periodic gate voltage may be a pulse wave, a sawtooth wave, or a triangular wave.

[0015] (Bolometer configuration) The bolometer 1 is used as a sensor for detecting infrared rays. As shown in FIG. 2, the bolometer 1 includes a substrate 11, a gate electrode 12, a drain electrode 14, a source electrode 15, a first film 16, and a second film 17.

[0016] (Board configuration) The substrate 11 is a Si substrate processed using a silicon wafer. For example, the substrate 11 may have a readout circuit formed thereon. For example, in order to ensure a sufficient temperature rise due to infrared absorption, the substrate 11 may be formed with a MEMS (Micro Electro Mechanical Systems) structure in which the lower part of the bolometer is hollow. For example, a polymer film such as Parylene (registered trademark) having low thermal conductivity may be formed on the substrate 11 in order to ensure heat insulation. For example, the substrate 11 may have an electrically insulating base insulating layer. Methods for forming the base insulating layer include a method of subjecting the substrate 11 to heat treatment, a method of directly forming the base insulating layer by CVD (Chemical Vapor Deposition), and a method of applying a solution of a polymer or a polymer precursor by spin coating and then heat treating it to form a polymer film. Examples of materials for the base insulating layer include silicon oxide, silicon nitride, polyimide, and Parylene (registered trademark). A drain electrode 14 and a source electrode 15 are formed on one surface of the substrate 11. A gate electrode 12 is formed on the other surface of the substrate 11. For example, the gate electrode 12 is formed over the entire area of ​​the other surface. A first film 16 is also laminated so as to cover the drain electrode 14 and the source electrode 15. For example, the drain electrode 14 and the source electrode 15 are patterned on the substrate 11 by a lift-off method using photolithography.

[0017] (gate electrode) The gate electrode 12 is provided on the other surface of the substrate 11 . A gate voltage can be applied to the gate electrode 12 . The gate voltage is the voltage applied to the gate electrode 12 relative to the source electrode 15. The gate voltage in this disclosure is swept periodically between an upper limit and a lower limit.

[0018] (Drain electrode) The drain electrode 14 is provided on one surface of the substrate 11 . A drain voltage can be applied to the drain electrode 14 . The drain voltage is a voltage applied to the drain electrode 14 relative to the source electrode 15. For example, a negative voltage may be applied to the drain electrode 14. For example, the drain electrode 14 is an electrode made of Au, Al, Ti, or an alloy mainly containing any of these. As an example, the drain electrode 14 may have a laminated structure in which an Au layer is laminated on a layer made of an alloy such as Ti.

[0019] (source electrode) The source electrode 15 is provided on one surface of the substrate 11 . For example, the source electrode 15 is connected to GND (ground). For example, the source electrode 15 is an electrode made of Au, Al, Ti, or an alloy mainly containing any of these. As an example, the source electrode 15 may have a laminated structure in which an Au layer is laminated on a layer made of an alloy such as Ti.

[0020] (first membrane) The first film 16 is an infrared light receiving section. The first film 16 connects the drain electrode 14 and the source electrode 15 . For example, a first film 16 covers the drain electrode 14 and the source electrode 15 . The following two examples of the first film 16 will be described.

[0021] (An example of the first membrane) The first film 16 includes a plurality of CNTs 161 . For example, in the present disclosure, the first film 16 has a CNT network formed by a plurality of CNTs 161 . In each of the CNTs 161 included in the first film 16, application of a gate voltage induces carriers in each of the CNTs 161. As a result, a drain current flows between the drain electrode 14 and the source electrode 15. The carriers induced in each CNT 161 change depending on the doping effect of the second film 17, which will be described later.

[0022] (Carbon Nano Tube: CNT) CNT161 is a fibrous material with a diameter of 0.6 to 1.5 nm and a length of 100 nm to 5.0 μm. The properties of CNT161 change depending on the arrangement of the six-membered rings in the circumferential direction. Regarding CNT161, a cylindrical CNT made from a single graphene sheet is called a single-walled CNT, a CNT formed by multiple layers of coaxially stacked CNTs of different diameters is called a multi-walled CNT, and a CNT formed by two layers is called a double-walled CNT. For example, the CNT 161 may be a single-walled CNT, a double-walled CNT, or a multi-walled CNT. By way of example, the CNTs 161 of the present disclosure are single-walled CNTs. CNT161 exists in two types: semiconducting, which exhibits semiconducting properties, and metallic, which exhibits metallic properties. Single-walled CNTs usually contain semiconducting CNTs and metallic CNTs in a 2:1 ratio. Therefore, when using a large amount of CNTs that exhibit one type of property, a separation process is necessary. For example, the CNT 161 may be a semiconducting CNT, which can improve the absolute value of the TCR in the bolometer 1.

[0023] (Another example of the first membrane) When the first film 16 includes a plurality of CNTs 161, it may further include oxide particles 162. In this case, it may further include a silane coupling agent. When the oxide particles 162 are modified with the silane coupling agent, the adhesion of the carbon nanotubes 161 to the oxide particles 162 is improved. For example, the silane coupling agent is 3-aminopropyltriethoxysilane (APTES). In the present disclosure, for example, the first film 16 includes oxide particles 162 .

[0024] For example, the oxide particles 162 may have a particulate form. Furthermore, the particle diameter of the oxide particles 162 may be approximately the same as the length of the carbon nanotubes 161. For example, the larger the particle diameter of the oxide particles 162, the easier it is for the long carbon nanotubes 161 to form a three-dimensional structure. For example, the smaller the particle diameter of the oxide particles 162, the easier it is for the short carbon nanotubes 161 to form a three-dimensional structure. If the network structure formed by multiple CNTs 161 is more likely to form a three-dimensional mesh structure, the number of conductive paths for each CNT 161 increases, and the first film 16 is more likely to have a low resistance value. A lower resistance value of the first film 16 makes it easier to reduce the resistance of the bolometer 1.

[0025] (oxide particles) Examples of the oxide particles 162 include, but are not limited to, oxides containing one or more of the following elements: Li, Al, Fe, Ni, Co, Mn, Bi, La, Cu, Sn, Zn, V, Zr, Pb, Sm, Y, W, Si, P, Ru, Ti, Ge, Ca, Ga, Cr, Cd, Mg, and Er. For example, the oxide particles 162 may contain two or more types of oxides. For example, the oxide particles 162 may be Zn 2-xThe oxide defined by the above chemical formula is a pyrophosphate, where T contains at least one element selected from Mg, Al, Si, Ti, V, Cr,' '' Mn, Fe, Co, Ni, Cu, Ga, Ge, Zr, Nb, Mo, Ag, In, Sn, Sb, La, Ta, W, Bi, and satisfies 0 < x < 2. For example, the oxide particles 162 contain Zn 2-z Mg z P2O7 (0 ≦ z ≦ 2) (hereinafter referred to as ZMPO). ZMPO is included in the pyrophosphate. For example, the oxide particles 162 contain Zn 2-z Mg z P2O7 (z = 0.4).

[0026] Another example of the oxide particles 162 includes BNFO, ZnO, and Er2O3. BNFO is BiNi1- y Fe y O3. (0 < y < 1) For example, the oxide particles 162 exhibit insulation. In the present disclosure, for example, the oxide particles 162 contain ZMPO and exhibit insulation.

[0027] When the first film 16 has the oxide particles 162, the thickness of the first film 16 is appropriately set. For example, the thickness of the first film 16 having the oxide particles 162 is 2 μm to 6 μm.

[0028] In the present disclosure, for example, the first film 16 includes CNT161 and the oxide particles 162. In a part of the first film 16, a plurality of carbon nanotubes 161 are dispersed on the surface of the oxide particles 162 so as to form a network in the film formed by the aggregation of the oxide particles 162. Therefore, the first film 16 constitutes a network structure formed by the entanglement of a plurality of carbon nanotubes. This network has a three-dimensional network structure. When the region where the second film 17 is formed is defined as region CO, in the region (region NE) adjacent to region CO, the carbon nanotubes 161 are removed by oxygen plasma treatment, and the proportion of the porous film described later may be increased.

[0029] (Second membrane) The second film 17 is selectively provided on the surface of the first film 16 . The second film 17 includes a polymer material and provides a doping effect to the first film 16 . The second film 17, through its doping action, provides the CNTs 161 contained in the first film 16 with the action of donating electrons (carriers induced by the gate voltage become electrons: N-type doping) or withdrawing electrons (carriers induced by the gate voltage become holes: P-type doping). The doping may shift the minimum value of the TCR curve to near the gate voltage of 0 V. CNTs are inherently electrically neutral. However, for example, in an atmospheric environment, CNTs 161 may be P-type doped with water or oxygen. Therefore, doping the first film 16 containing CNTs 161 makes it easier to stabilize the measured value of the drain current. This makes it less likely that the TCR curve will fluctuate significantly each time the drain current is measured. Furthermore, N-type doping may be used to cancel the P-type doping caused by oxygen or water adsorbed to the CNTs 161. For example, the second film 17 may contain PMMA (poly methyl methacrylate, P4VP (poly(4-vinylpyridine)), or P4VBM (poly(4-vinylpyridine-co-bytyl methacrylate)). For example, a PMMA film formed using a PMMA solution dissolved in anisole dopes the CNTs 161 contained in the first film 16.

[0030] Alternatively, the second film 17 may be an insulating film made of silicon oxide, alumina, or the like. In the present disclosure, the second film 17 comprises PMMA.

[0031] In the following description, the first film 16 exhibits the same tendency regardless of the presence or absence of the oxide particles 162. Therefore, it is sufficient that the first film 16 contains at least the CNTs 161.

[0032] FIG. 3 shows the transport properties of a bolometer 1 having a CNT network in the first film 16, in which the CNTs 161 are p-doped. In Figure 3, when the gate voltage for bolometer 1 is swept between -8V and 8V and then back towards -8V, the gate voltage (V g The drain current (I d ) is shown as a transport property. Figure 3 shows the drain voltage (V d )(V d = -3.0V). As a supplement, Figure 3 shows the gate current (I g ) values ​​are also shown. When the ambient temperature of the test device was increased from 293K to 303K while other conditions were maintained, the drain current I d The value of increases.

[0033] 4 is a curve (TCR curve) showing the TCR value calculated based on the transport characteristics at 293 K and 303 K versus each gate voltage value. In the present disclosure, a negative TCR is shown because semiconducting carbon nanotubes are used. In Figure 4, the gate voltage is set to the lower limit LL (V g =-8.0V) to the upper limit UL(V g The path from when the gate voltage reaches the upper limit UL (V g =8.0V) to the lower limit LL(V g = -8.0V) is expressed as the path Fall. At this time, TCR hysteresis is confirmed. In the Rise path, the gate voltage V g At 2.0V, the absolute value of TCR is maximized, TCR=-18% / K. gAt 4.0V, the absolute value of TCR is maximized, TCR=-12% / K. g Even at 2.0V, TCR=-10% / K can be confirmed.

[0034] 4, the first film 16 contains oxide particles 162. The absolute value of each TCR when the oxide particles 162 are contained is greater than the absolute value of each TCR when the oxide particles 162 are not contained.

[0035] In explaining Figure 5, the gate voltage (V g = 0V, 1.0V) at 293K. d and drain voltage V d and the drain current I at 303K d and drain voltage V d and acquired a relationship. Figure 5 shows the data calculated based on the acquired data. d This shows the dependence of TCR on the gate voltage V g It can be seen that the absolute value of TCR is less than 10 (TCR>-10% / K) even in this case. Therefore, for a given gate voltage V g When the drain voltage V d Rather than sweeping the drain voltage V d When the gate voltage V g It is understood that sweeping the TCR makes it easier for the absolute value of the TCR to become large.

[0036] From the above, in the bolometer 1 of the present disclosure, during the sweep, the drain current I d The goal is to measure the following: Also, the gate voltage V g The gate voltage V where the absolute value of TCR is maximum is g If there is a value X, the drain current Id Measurements may be made.

[0037] As shown below, bolometer 1 is synchronized with a certain period and the drain current I d Measurements are taken.

[0038] (Upper and lower limits of gate voltage) As mentioned above, the gate voltage V g The gate voltage V at which the absolute value of TCR reaches its maximum value is swept periodically between the upper and lower limits. g The value of X is the gate voltage V g The following example will be described, in which the upper or lower limit value is set to .

[0039] In FIG. 6, for example, in bolometer 1, the drain voltage is negative (V d = -3V), when the gate voltage V g is periodically swept between an upper limit value UL1 and a lower limit value LL1. At this time, the upper limit value UL1 is the gate voltage V g The lower limit LL1 is the gate voltage V g is. Gate voltage V g is swept from the lower limit LL1 to the upper limit UL1. At this time, the timing at which the upper limit UL1 is reached (t=t1, t3...t 2n+1 ) and the drain current I d Measurements may be made.

[0040] Also, the gate voltage V g The timing at which the sweep starts from the upper limit UL1 to the lower limit LL1 (t=t2, t4...t 2n ) and the drain current I d Measurements may be made.

[0041] As shown in Figure 7, the gate voltage V g The waveform of is not limited to that shown in Figure 6. g Examples of the waveform include a pulse wave, a sawtooth wave, and a triangular wave. Drain current I d The gate voltage V g may be positive, negative or 0V, and the gate voltage V g Just use

[0042] In FIG. 8, for example, in bolometer 1, the drain voltage V d is negative (V d =-3.0V), the gate voltage is swept periodically between an upper limit value UL2 and a lower limit value LL2. At this time, the lower limit value LL2 is the gate voltage when the gradient of the TCR curve is 0. Gate voltage V g is swept from the upper limit UL2 to the lower limit LL2. At this time, the timing at which the lower limit LL2 is reached (t=t1, t3...t 2n+1 ) and the drain current I d Measurements may be made.

[0043] Also, the gate voltage V g The timing at which the sweep starts from the lower limit LL2 to the upper limit UL2 (t=t2, t4...t 2n ) and the drain current I d Measurements may be made.

[0044] (Infrared detection method) The infrared detection method according to this embodiment will be described. The infrared detection method of this embodiment is carried out according to the flow shown in FIG.

[0045] First, the operator applies a drain voltage V d is applied (step ST10: step of applying drain voltage). Specifically, the worker applies a drain voltage V d is applied.

[0046] Next, the operator applies a gate voltage V to the gate electrode 12 while periodically varying between the upper and lower limits. g is swept (step ST11: step of sweeping the gate voltage). Specifically, the operator uses the sweep unit 2 to sweep the gate voltage with periodicity.

[0047] For example, the operator may g The relationship between the TCR and the drain current may be measured in advance, and then the upper and lower limits may be determined. Hysteresis of the TCR is observed in the first film 16 containing the CNTs 161, regardless of the presence or absence of the oxide particles 162. That is, when the gate voltage is swept from the upper limit to the lower limit, or from the lower limit to the upper limit, the absolute value of the TCR may reach a maximum value at some point. The drain current I d The operator must measure the gate voltage V g The upper and lower limits are determined.

[0048] Next, the operator calculates the drain current I d The measurement timing is synchronized, and the bolometer 1 detects the infrared rays (step ST12). Here, the gate voltage V swept by ST12 g At a specific timing in the cycle, infrared light is detected so that the absolute value of the TCR can be maximized (completion).

[0049] (Action and effect) According to the bolometer 1 of the present disclosure, the gate voltage V g By sweeping the value, the drain current I d Measurements can be made. Therefore, the bolometers of the present disclosure tend to have high TCR.

[0050] As a comparative example, a bolometer in which a CNT network is used as a bolometer resistor is shown. In such a bolometer resistor, the drain current I d There was a concern that the hysteresis of the bolometer resistor would cause a stable TCR. In addition, when the bolometer resistor contains CNTs 161 and oxide particles 162, the TCR may take a large value and the drain current I d The hysteresis of the In contrast, according to the bolometer 1 of the present disclosure, the gate voltage V g By sweeping the value, the drain current I d Measurements can be made. Therefore, the bolometer 1 of the present disclosure makes it easy to stably obtain a TCR that is a predetermined value.

[0051] In addition, the bolometer of the present disclosure has a gate voltage V g and a gate electrode 12 to which a drain voltage V d a drain electrode 4 to which a gate voltage V can be applied, a source electrode 15, and a first film 16 connecting the drain electrode 14 and the source electrode 15 and including a carbon nanotube 161; g is swept periodically between the upper limit value and the lower limit value, the following effects can be obtained. The bolometer of the present disclosure is a bolometer that has a periodicity between an upper limit value and a lower limit value while controlling the gate voltage V g By sweeping the value, the drain current I d Therefore, the bolometer 1 of the present disclosure can be easily made to have a high TCR.

[0052] In addition, in the bolometer of the present disclosure, the upper limit or lower limit is the gate voltage V when the gradient of the resistance temperature coefficient is 0. gTherefore, the drain current I d This also has the effect of making it easier to stably obtain the TCR with the maximum absolute value.

[0053] In addition, in the bolometer of the present disclosure, the lower limit is a negative value of the gate voltage V g By this, the gate voltage V g is swept from the upper limit to the negative lower limit, g The absolute value of TCR is more likely to be maximum than when the

[0054] Furthermore, in the bolometer of the present disclosure, "the first film 16 further includes oxide particles 162," which allows each CNT 161 contained in the first film 16 to be attached so as to lean against the surface of the oxide particles 162, making it easier to arrange each CNT 161 three-dimensionally. This increases the number of conductive paths for each CNT 161 in the network structure. This makes it easier for the first film 16, which is the resistor portion of the bolometer 1, to obtain a low resistance value. Therefore, the bolometer of the present disclosure makes it easier to obtain a low resistance value.

[0055] Furthermore, in the bolometer of the present disclosure, "the oxide particles 162 contain at least pyrophosphate," which allows the TCR to have a large value and makes it easier for the first film 16 to have a low resistance value.

[0056] Furthermore, in the bolometer of the present disclosure, the first film 16 further contains a silane coupling agent, which improves the adhesion of the carbon nanotubes 161 to the oxide particles 162.

[0057] Furthermore, the bolometer of the present disclosure "further comprises a second film 17 provided on the surface of the first film 16 and performing a doping action on the first film 16," thereby achieving the following effect. In the bolometer of the present disclosure, the first film 16 containing the CNTs 161 is doped, thereby increasing the drain current I d This makes it easier to stabilize the measured value of the drain current I d This makes it less likely that the measurement will fluctuate significantly each time.

[0058] Furthermore, in the bolometer of the present disclosure, the following effect can be obtained by "the second film 17 including a polymer material." In the bolometer of the present disclosure, the first film 16 containing the CNTs 161 is doped, thereby increasing the drain current I d This makes it easier to stabilize the measured value of the drain current I d This makes it less likely that the measurement will fluctuate significantly each time.

[0059] Furthermore, in the bolometer of the present disclosure, the following effect can be obtained by "the second film containing PMMA, P4VP, or P4VBM." In the bolometer of the present disclosure, the first film 16 containing the CNTs 161 is doped, thereby increasing the drain current I d This makes it easier to stabilize the measured value of the drain current I d This makes it less likely that the measurement will fluctuate significantly each time.

[0060] Furthermore, in the bolometer of the present disclosure, since "the carbon nanotubes (CNT161) are semiconducting carbon nanotubes," an effect can be obtained in which "the absolute value of the TCR of the bolometer 1 can be improved."

[0061] (Variation) (Part 1) As shown in Figure 10, the drain voltage V d The drain voltage V applied to the bolometer 1 of the present disclosure may be a pulse waveform. d However, as shown in Figure 5 again, the drain current I dSince the minimum value of TCR is confirmed when V is negative, bolometer 1 is d may be applied. The drain current I d The drain voltage V d must be applied to the drain electrode 14.

[0062] (Part 2) The bolometer 1 may have a configuration similar to that of the bolometer 1B. As shown in FIG. 11, the bolometer 1B includes a substrate 11, a gate electrode 12, an insulating film 13, a drain electrode 14, a source electrode 15, a first film 16, and a second film 17. The bolometer 1B differs from the bolometer 1 in that it includes an insulating film 13 and a gate electrode 12 on the drain electrode 14 (source electrode 15) side as viewed from the substrate 11. The gate electrode 12 is provided on a portion P of the surface of the substrate 11. In addition, components common to those disclosed above are given the same reference numerals and detailed description thereof will be omitted.

[0063] (insulating film) An insulating film 13 is provided on a part of the surface of the substrate 11 via a gate electrode 12. The insulating film 13 may be substantially doped with respect to the first film 16. The insulating film 13 is laminated so as to cover the surface of the substrate 11 and the surface of the gate electrode 12. The first film 16 covers the drain electrode 14 and the source electrode 15, thereby increasing the contact area between the CNTs 161 in the CNT network and the drain electrode 14 or the source electrode 15, thereby enabling the resistance of the bolometer 1 to be reduced. For example, the insulating film 13 may have a thickness sufficient to protect the first film 16 from P-type doping by water or oxygen.

[0064] Second Embodiment Hereinafter, an embodiment according to the present disclosure will be described with reference to the drawings. An example of the configuration of a bolometer according to the present disclosure will be described below with reference to FIG.

[0065] (composition) The bolometer comprises a gate electrode 12m to which a gate voltage can be applied, a drain electrode 14m to which a drain voltage can be applied, a source electrode 15m, and a first film 16m that connects the drain electrode 14m and the source electrode 15m and includes a carbon nanotube 161m, and the gate voltage is swept periodically between an upper limit value and a lower limit value.

[0066] (Action and effect) According to the bolometer 1m of the present disclosure, by sweeping the gate voltage while having a periodicity between the upper limit value and the lower limit value, the drain current I d Measurements can be made. Therefore, the bolometers of the present disclosure tend to have high TCR.

[0067] Third Embodiment Hereinafter, an embodiment according to the present disclosure will be described with reference to the drawings. An example of an infrared detection method according to the present disclosure will be described below with reference to FIG. The infrared detection method according to the present disclosure is carried out according to the flow shown in FIG.

[0068] The infrared detection method includes a step of applying a drain voltage to a drain electrode of a bolometer having a gate electrode, a drain electrode, a source electrode, and a first film connecting the drain electrode and the source electrode and containing carbon nanotubes (step ST10m: step of applying a drain voltage), and a step of sweeping a gate voltage to the gate electrode while having a periodicity between an upper limit value and a lower limit value (step ST11m: step of sweeping a gate voltage).

[0069] (Action and effect) According to the infrared detection method of the present disclosure, by sweeping the gate voltage while having a periodicity between the upper limit value and the lower limit value, the drain current I d Measurements can be made. Therefore, the infrared detection method of the present disclosure is prone to high TCR.

[0070] Although the present disclosure has been described above with reference to the embodiments, the present disclosure is not limited to the above-described embodiments. Various modifications that can be understood by those skilled in the art can be made to the configuration and details of the present disclosure within the scope of the present disclosure. Furthermore, each embodiment can be combined with other embodiments as appropriate.

[0071] <Other variations>

[0072] (Infrared absorbing layer) In order to improve the amount of infrared absorption, an infrared absorbing layer may be provided on the bolometer 1 disclosed above. The infrared absorbing layer is provided on the surface of the second film 17. Materials that can be used for the infrared absorption layer include gold black, carbon materials such as carbon nanotubes, carbon nanohorns, or carbon black, or composite materials of these carbon materials and polymer resins. When the above composite materials are used, PVA (polyvinyl alcohol), PMMA, P4VP, etc. can be used as the polymer resin, but the material is not limited to these three types as long as it can uniformly disperse CNTs and maintain the structure of the polymer resin.

[0073] A part or all of the above-described embodiments can be described as, but not limited to, the following supplementary notes.

[0074] (Appendix 1) a gate electrode to which a gate voltage can be applied; a drain electrode to which a drain voltage can be applied; A source electrode; a first film connecting the drain electrode and the source electrode and including carbon nanotubes; the gate voltage is swept periodically between an upper limit value and a lower limit value; Bolometer.

[0075] (Appendix 2) The upper limit value or the lower limit value is a gate voltage when the gradient of the temperature coefficient of resistance is 0. bolometer as described in Appendix 1.

[0076] (Appendix 3) The lower limit is a gate voltage that is a negative value. 10. A bolometer according to claim 1 or 2.

[0077] (Appendix 4) the first film contains oxide particles; 4. A bolometer according to any one of claims 1 to 3.

[0078] (Appendix 5) The oxide particles contain at least pyrophosphate. A bolometer as described in Appendix 4.

[0079] (Appendix 6) The first film contains a silane coupling agent. 6. A bolometer according to claim 4 or 5.

[0080] (Appendix 7) a second film provided on the surface of the first film and performing a doping action on the first film; Further provided with 7. A bolometer according to any one of claims 1 to 6.

[0081] (Appendix 8) the second membrane comprises a polymeric material; bolometer as described in Appendix 7.

[0082] (Appendix 9) The second film comprises PMMA, P4VP, or P4VBM. 10. A bolometer according to claim 7 or 8.

[0083] (Appendix 10) the drain voltage is a negative value; 10. A bolometer according to any one of claims 1 to 9.

[0084] (Appendix 11) The carbon nanotubes are semiconducting carbon nanotubes. 11. A bolometer according to any one of claims 1 to 10.

[0085] (Appendix 12) 12. A bolometer according to any one of claims 1 to 11; a sweep unit that sweeps the gate voltage; Including, Infrared detection device.

[0086] (Appendix 13) A bolometer including a gate electrode, a drain electrode, a source electrode, and a first film connecting the drain electrode and the source electrode and including carbon nanotubes, applying a drain voltage to the drain electrode; sweeping a gate voltage of the gate electrode between an upper limit value and a lower limit value with a periodicity; Including, Infrared detection method. [Explanation of symbols]

[0087] 100 Infrared detection device 1 bolometer 2 Sweep section 11 Circuit Board 12 gate electrode 13 Insulating film 14 Drain electrode 15 Source electrode 16 First membrane 161 Carbon nanotubes 162 Oxide particles 17 Second membrane 1B Bolometer 1m bolometer 12m gate electrode 14m drain electrode 15m source electrode 16m first membrane 161m carbon nanotube CO area NE area Rise Route Fall Path LL Lower limit LL1 lower limit LL2 lower limit UL upper limit UL1 upper limit UL2 upper limit Vd Drain voltage Vg Gate voltage Id Drain current

Claims

1. a gate electrode to which a gate voltage can be applied; a drain electrode to which a drain voltage can be applied; A source electrode; a first film connecting the drain electrode and the source electrode and including carbon nanotubes; the gate voltage is swept periodically between an upper limit value and a lower limit value; Bolometer.

2. the upper limit value or the lower limit value is a gate voltage when the gradient of the temperature coefficient of resistance is 0; 2. The bolometer of claim 1.

3. The lower limit is a gate voltage that is a negative value.

3. The bolometer of claim 2.

4. the first film contains oxide particles; A bolometer according to any one of claims 1 to 3.

5. The first film contains a silane coupling agent.

5. The bolometer of claim 4.

6. a second film provided on the surface of the first film and performing a doping action on the first film; Further provided with 5. The bolometer of claim 4.

7. the drain voltage is a negative value; A bolometer according to any one of claims 1 to 3.

8. The carbon nanotubes are semiconducting carbon nanotubes. A bolometer according to any one of claims 1 to 3.

9. A bolometer according to any one of claims 1 to 3; a sweep unit that sweeps the gate voltage; Including, Infrared detection device.

10. A bolometer including a gate electrode, a drain electrode, a source electrode, and a first film connecting the drain electrode and the source electrode and including carbon nanotubes, applying a drain voltage to the drain electrode; sweeping a gate voltage of the gate electrode between an upper limit value and a lower limit value with a periodicity; Including, Infrared detection method.

Images