JP2019158751A - Radiation detector and manufacturing method of the same - Google Patents

Abstract

To provide a radiation detector capable of improving detection efficiency, and a manufacturing method of the same.SOLUTION: According to an embodiment, a radiation detector includes a first conductive layer, a second conductive layer, and an organic semiconductor layer. The organic semiconductor layer is provided between the first conductive layer and the second conductive layer. The organic semiconductor layer includes a first region and a second region. The second region is provided between the first region and the second conductive layer. The second region includes a plurality of inorganic particles. The first region does not include the plurality of inorganic particles, or a first weight concentration of the plurality of inorganic particles in the first region smaller than a second weight concentration of the plurality of inorganic particles in the second region.SELECTED DRAWING: Figure 1

Description

  Embodiments described herein relate generally to a radiation detector and a manufacturing method thereof.

  In a radiation detector, improvement in detection efficiency is desired.

US Patent Application Publication No. 2017 / 0168166A1

  Embodiments of the present invention provide a radiation detector capable of improving detection efficiency and a method for manufacturing the same.

  According to an embodiment of the present invention, the radiation detector includes a first conductive layer, a second conductive layer and an organic semiconductor layer. The organic semiconductor layer is provided between the first conductive layer and the second conductive layer. The organic semiconductor layer includes a first region and a second region. The second region is provided between the first region and the second conductive layer. The second region includes a plurality of inorganic particles. The first region does not include the plurality of inorganic particles, or the first weight concentration of the plurality of inorganic particles in the first region is lower than the second weight concentration of the plurality of inorganic particles in the second region. .

FIG. 1 is a schematic cross-sectional view illustrating a radiation detector according to the first embodiment. FIG. 2 is a schematic view illustrating the radiation detector according to the first embodiment. FIG. 3 is an electron micrograph image illustrating the radiation detector according to the first embodiment. FIG. 4 is a schematic view illustrating the radiation detector according to the first embodiment. FIG. 5 is a graph illustrating characteristics of the radiation detector. FIG. 6 is a graph illustrating characteristics of the radiation detector. FIG. 7 is a graph illustrating characteristics of the radiation detector. FIG. 8 is a graph illustrating characteristics of the radiation detector. FIG. 9A and FIG. 9B are schematic cross-sectional views illustrating a method for manufacturing a radiation detector. FIG. 10A and FIG. 10B are schematic cross-sectional views illustrating a method for manufacturing a radiation detector. FIG. 11A to FIG. 11C are schematic cross-sectional views illustrating a method for manufacturing a radiation detector. FIG. 12 is a schematic cross-sectional view illustrating a radiation detector according to the second embodiment. FIG. 13 is a schematic cross-sectional view illustrating a part of the radiation detector according to the second embodiment. FIG. 14 is a schematic cross-sectional view illustrating a part of the radiation detector according to the embodiment. FIG. 15 is a circuit diagram illustrating a part of the radiation detector according to the embodiment. FIG. 16 is a schematic cross-sectional view illustrating a radiation detector according to the embodiment. FIG. 17 is a schematic cross-sectional view illustrating the radiation detector according to the embodiment.

Embodiments of the present invention will be described below with reference to the drawings.
The drawings are schematic or conceptual, and the relationship between the thickness and width of each part, the size ratio between the parts, and the like are not necessarily the same as actual ones. Even in the case of representing the same part, the dimensions and ratios may be represented differently depending on the drawings.
In the present specification and drawings, the same elements as those described above with reference to the previous drawings are denoted by the same reference numerals, and detailed description thereof is omitted as appropriate.

(First embodiment)
FIG. 1 is a schematic cross-sectional view illustrating a radiation detector according to the first embodiment.
As shown in FIG. 1, the radiation detector 110 according to the first embodiment includes a first conductive layer 10, a second conductive layer 20, and an organic semiconductor layer 30.

  In this example, a first base 51 and a second base 52 are further provided. The first conductive layer 10 is provided between the first base 51 and the second base 52. The second conductive layer 20 is provided between the first conductive layer 10 and the second base 52.

  At least one of these substrates may be a substrate. For example, the first substrate 51 may be a resin substrate. The first base 51 includes, for example, at least one of PEN and PET. For example, the second base 52 may include, for example, glass (soda lime glass, non-alkali glass, or the like).

  The organic semiconductor layer 30 is provided between the first conductive layer 10 and the second conductive layer 20.

  The organic semiconductor layer 30 includes, for example, a first semiconductor region. The first semiconductor region is a polymer. The molecular weight of the material of the first semiconductor region is, for example, 5,000 or more and 5,000,000 or less. In the embodiment, the organic semiconductor layer 30 may further include a second semiconductor region. The second semiconductor region is, for example, a low molecule. The molecular weight of the material of the second semiconductor region is, for example, 10 or more and less than 5,000. For example, the first conductivity type is p-type and the second conductivity type is n-type.

  The first semiconductor region includes, for example, polythiophene. The first semiconductor region includes, for example, P3HT (Poly (3-hexylthiophene)) and F8T2 ([Poly [(9,9-dioctyl-9H-fluorene-2,7-diyl) -alt-2,2'-bithiophene]). -5,5'-diyl)]]) at least one selected from the group consisting of.

The second semiconductor region includes, for example, fullerene. The second semiconductor region includes, for example, PCBM. The second semiconductor region includes, for example, PC ₆₁ BM ([6,6] -phenyl C61 butyric acid methyl ester).

  In the embodiment, the organic semiconductor layer 30 includes a first region R1 and a second region R2.

  The second region R2 is provided between the first region R1 and the second conductive layer 20.

The second region R2 includes a plurality of inorganic particles 35. The plurality of inorganic particles 35 include, for example, at least one selected from the group consisting of Bi ₂ O ₃ and ZnO. The density of the plurality of inorganic particles 35 is higher than the density of the organic semiconductor, for example. When the radiation 81 is incident on the plurality of inorganic particles 35, the radiation 81 is easily scattered by the inorganic particles 35.

  The first region R1 does not include the plurality of inorganic particles 35. Alternatively, the concentration (first weight concentration) of the plurality of inorganic particles 35 in the first region R1 is lower than the concentration (second weight concentration) of the plurality of inorganic particles 35 in the second region R2.

  For example, in the organic semiconductor layer 30, a region where the plurality of inorganic particles 35 are provided and a region where the plurality of inorganic particles 35 are not substantially provided are provided.

  As shown in FIG. 1, for example, the radiation 81 is incident on the first conductive layer 10 in the direction from the first conductive layer 10 to the second conductive layer 20. The first base 51 serves as an incident surface for the radiation 81. The radiation 81 incident on the first conductive layer 10 enters the organic semiconductor layer 30. At least a part of the radiation 81 passes through the first region R1 of the organic semiconductor layer 30 and enters the second region R2. In the second region R2, at least a part of the radiation 81 is irradiated to the plurality of inorganic particles 35. Back scattering occurs in the plurality of inorganic particles 35. Thereby, at least a part of the radiation 81 is absorbed by the organic semiconductor included in the second region R2 and is also absorbed by the organic semiconductor included in the first region R1. The radiation 81 is efficiently absorbed by the organic semiconductor.

  In the organic semiconductor, a movable charge is generated by the energy of the radiation 81. By applying a bias voltage between the first conductive layer 10 and the second conductive layer 20, this charge is taken out.

  For example, a detection circuit 70 is provided. The detection circuit 70 is electrically connected to the first conductive layer 10 and the second conductive layer 20. The electrical connection is performed by, for example, the first wiring 71 connected to the first conductive layer 10 and the second wiring 72 connected to the second conductive layer 20. The detection circuit 70 includes a charge amplifier. The first conductive layer 10 (first wiring 71) and the second conductive layer 20 (second wiring 72) are electrically connected to the input of the charge amplifier. The output of the charge amplifier becomes the output signal OS.

  In the embodiment, the first region R <b> 1 is provided on the incident side of the radiation 81. A second region R <b> 2 is provided on the downstream side of the radiation 81. Thereby, the radiation 81 back-scattered by the plurality of inorganic particles 35 provided in the second region R2 can be efficiently incident on the organic semiconductor. Thereby, high conversion efficiency is obtained. In the embodiment, a radiation detector capable of improving detection efficiency can be provided.

  As shown in FIG. 1, the organic semiconductor layer 30 includes a first surface 30a and a second surface 30b. The first surface 30 a faces the first conductive layer 10. The second surface 30 b faces the second conductive layer 20. For example, the first surface 30a is a part of the first region R1. For example, the second surface 30b is a part of the second region R2.

  The thickness of the first region R1 (first thickness t1) may be greater than the thickness of the second region R2 (second thickness t2). This makes it easy to obtain high conversion efficiency, as will be described later.

  The direction from the first conductive layer 10 to the second conductive layer 20 is the first direction. The first direction is the Z-axis direction. The first thickness t1 and the second thickness t2 are lengths along the first direction.

FIG. 2 is a schematic view illustrating the radiation detector according to the first embodiment.
FIG. 2 illustrates the concentration C0 of the plurality of inorganic particles 35 in the organic semiconductor layer 30. The horizontal axis in FIG. 2 is the position in the Z-axis direction. The vertical axis is the concentration C0.

  As shown in FIG. 2, in the organic semiconductor layer 30, a region having a high concentration C0 corresponds to the second region R2. A region having a low density C0 corresponds to the first region R1. In the organic semiconductor layer 30, the concentration C0 may change continuously.

  The peak (maximum value) of the concentration C0 in the organic semiconductor layer 30 is defined as the peak concentration Cp (maximum concentration). In the organic semiconductor layer 30, a concentration that is ½ of the peak concentration Cp is set to a concentration Cp / 2. There is a position where the density C0 becomes the density Cp / 2 (position along the Z-axis direction). A distance (a distance along the Z-axis direction) between this position and the second surface 30b may correspond to the second thickness t2. The distance between this position and the first surface 30a (the distance along the Z-axis direction) may correspond to the first thickness t1.

  When the concentration C0 continuously changes in the organic semiconductor layer 30, the first region R1 and the second region R2 may be determined as described above.

  The thickness of the organic semiconductor layer 30 is, for example, the sum of the first thickness t1 and the second thickness t2. The thickness of the organic semiconductor layer 30 is, for example, 10 μm or more and 1000 μm or less. When the thickness of the organic semiconductor layer 30 is 10 μm or more, the radiation 81 is effectively absorbed by the organic semiconductor layer 30. Thereby, for example, high detection efficiency is obtained. The thickness of the organic semiconductor layer 30 may be, for example, 100 μm or more. This makes it easier to obtain high detection efficiency. When the thickness of the organic semiconductor layer 30 is 10 μm or more, for example, noise can be suppressed.

  When the thickness of the organic semiconductor layer 30 becomes excessively thick, the bias voltage becomes excessively high. A practical bias voltage can be obtained when the thickness of the organic semiconductor layer 30 is 1000 μm or less. An easy-to-use bias voltage can be obtained when the thickness of the organic semiconductor layer 30 is 500 μm or less.

  Noise can be suppressed when the thickness of the organic semiconductor layer 30 is, for example, 10 μm or more and 500 μm or less.

  There is a method of forming an organic semiconductor layer by a coating method. In the coating method, for example, a powder containing an organic semiconductor is dissolved in a solvent.

  If a thick organic semiconductor layer is formed by a coating method, it is difficult to obtain a uniform layer. For example, a method in which a thin organic semiconductor layer is formed by a coating method and another thin organic semiconductor layer is stacked thereon may be considered. Also in this case, it is difficult to uniformly stack a plurality of organic semiconductor layers.

  Furthermore, when the organic semiconductor layer 30 is intended to form a structure including a plurality of inorganic particles 35 by a coating method, the uniformity further deteriorates. For example, it has been found that a distribution according to the diameter of the plurality of inorganic particles 35 is easily formed. For example, the inorganic particles 35 having a large particle size sink and tend to gather under the coating film. Even when a plurality of inorganic particles 35 having a small average particle diameter are used, the diameters of the plurality of inorganic particles 35 have a distribution, and therefore non-uniformity is likely to occur depending on the diameter distribution.

  On the other hand, a method of forming the organic semiconductor layer 30 by a pressure molding method (for example, a powder molding method) is conceivable. In the powder molding method, for example, a powder containing an organic semiconductor is pressed by pressure. Thereby, the organic semiconductor layer 30 is obtained. In this method, it is easy to form the organic semiconductor layer 30 including the plurality of inorganic particles 35 uniformly. Uniform dispersibility substantially independent of the diameter of the plurality of inorganic particles 35 is obtained. In the embodiment, the organic semiconductor layer 30 may be formed by, for example, a powder molding method.

  Hereinafter, an example of the organic semiconductor layer 30 according to the embodiment will be described.

FIG. 3A and FIG. 3B are electron micrograph images illustrating the radiation detector according to the first embodiment.
These electron microscopic photographic images are SEM photographic images. FIG. 3A corresponds to a region including the second surface 30 b of the organic semiconductor layer 30. FIG. 3B corresponds to a region including the first surface 30 a of the organic semiconductor layer 30. From these drawings, it can be seen that the first surface 30a is relatively flat and the second surface 30b has irregularities.

FIG. 4A and FIG. 4B are schematic views illustrating a part of the radiation detector according to the first embodiment.
These drawings schematically show the states of the first surface 30 a and the second surface 30 b of the organic semiconductor layer 30. As shown in FIG. 4A, the first surface 30a is relatively flat. On the other hand, the second surface 30b has irregularities 30dp. The unevenness 30dp of the second surface 30b is larger than the unevenness of the first surface 30a.

  Such a structure is obtained when the organic semiconductor layer 30 is formed by a pressure molding method (for example, a powder molding method). For example, the upper surface of a layer formed by a coating method or the like is easily leveled. For this reason, the flatness tends to be substantially the same between the upper surface and the lower surface.

  When a conductive layer is formed on such an organic semiconductor layer 30, a part of the conductive layer enters the unevenness 30dp.

  As shown in FIG. 4B, the organic semiconductor layer 30 includes a surface (second surface 30 b) that faces the second conductive layer 20. This surface has irregularities 30 dp. At least a part of the second conductive layer 20 is provided in the recess of the unevenness 30 dp. For example, the contact area between the organic semiconductor layer 30 and the second conductive layer 20 is increased. For example, sensitivity is improved.

  As will be described later, another layer (intermediate layer) may be provided between the organic semiconductor layer 30 and the second conductive layer 20. In this case, a part of the intermediate layer may be provided in the recess.

Hereinafter, an example of the simulation result of the characteristics of the radiation detector will be described.
In the simulation, in order to simplify the model, the second region R2 includes only a plurality of inorganic particles 35 and does not include an organic semiconductor. On the other hand, the first region R1 includes only an organic semiconductor and does not include a plurality of inorganic particles 35. The case where the plurality of inorganic particles 35 are Bi ₂ O _{3 and} the case of ZnO are examined. The layer of the plurality of inorganic particles 35 corresponds to the second region R2 illustrated in FIG. The layer containing only the organic semiconductor corresponds to the first region R1 illustrated in FIG.

  In the simulation model, the thickness of the organic semiconductor layer 30 is constant at 300 μm. In the following, the thickness ratio ta is assumed to be t2 / (t1 + t2).

  In the first reference example, the thickness ratio ta is zero. In the first reference example, the layer of the plurality of inorganic particles 35 is not provided. In the first reference example, an organic semiconductor layer having a thickness of 300 μm is provided. In the first reference example, the detection rate obtained by simulation is about 20.4%.

  In this example, the “detection rate” is the ratio (%) of the number of particles energy-deposited in the organic semiconductor layer to the number of particles of radiation 81 (β rays) incident on the organic semiconductor layer.

In the second reference example, a layer of a plurality of inorganic particles 35 (Bi ₂ O ₃ ) having a thickness of 150 μm is provided on the first conductive layer 10 side. An organic semiconductor layer having a thickness of 150 μm is provided on the second conductive layer 20 side. In the second reference example, the radiation 81 (β rays in this example) is incident from the side of the plurality of inorganic particles 35. In the second reference example, the detection rate obtained by the simulation is about 13.6%.

  In the second reference example, the radiation 81 first enters the layer of the plurality of inorganic particles 35. It is considered that most of the radiation 81 is backscattered by a plurality of layers of inorganic particles 35. Therefore, it is considered that the amount of radiation 81 incident on the organic semiconductor layer is small. For this reason, it is considered that the detection rate is low in the second reference example.

  On the other hand, in the first reference example, the radiation 81 is incident on the 300 μm organic semiconductor layer. Since the organic semiconductor layer is thick, the radiation 81 is easily absorbed by the organic semiconductor layer. For this reason, it is considered that the detection rate in the first reference example is higher than the detection rate in the second reference example.

Hereinafter, an example of a simulation result of characteristics when the thickness ratio ta is changed will be described.
5 and 6 are graphs illustrating characteristics of the radiation detector.
FIG. 5 corresponds to the case where the plurality of inorganic particles 35 are Bi ₂ O ₃ . FIG. 6 corresponds to the case where the plurality of inorganic particles 35 are ZnO. The horizontal axis of these figures is the thickness ratio ta. As already described, the thickness ratio ta is t2 / (t1 + t2). The vertical axis represents the detection rate EF1 (%) of the radiation 81 (β rays in this example). In these figures, the characteristic SP00 of the first reference example is also displayed.

As shown in FIG. 5, when the plurality of inorganic particles 35 are Bi ₂ O ₃ , the detection rate EF1 is 22.8% or more when the thickness ratio ta is in the range of 0.16 to 0.5. When the thickness ratio ta is about 0.33, the detection rate EF1 shows a peak, which is about 23.4%. When the thickness ratio ta exceeds about 0.33, the detection rate EF1 tends to decrease.

  As shown in FIG. 6, when the plurality of inorganic particles 35 are ZnO, the detection rate EF1 is as high as 23.3% or more when the thickness ratio ta is in the range of 0.16 to 0.5. When the thickness ratio ta is about 0.33, the detection rate EF1 shows a peak, which is about 23.4%. When the thickness ratio ta exceeds about 0.33, the detection rate EF1 tends to decrease slightly.

  In the embodiment, the thickness ratio ta is preferably 0.5 or less. A high detection rate EF1 is obtained. The thickness ratio ta is preferably 0.16 or more. A high detection rate EF1 is obtained.

  Thus, the first thickness t1 of the first region R1 is preferably thicker than the second thickness t2 of the second region R2.

FIG. 7 is a graph illustrating characteristics of the radiation detector.
The horizontal axis of FIG. 7 represents the weight concentration Rw of the plurality of inorganic particles 35 (Bi ₂ O _{3 in} this example). The weight concentration Rw is the weight concentration of the plurality of inorganic particles 35 with respect to the organic semiconductor layer 30 in the second region R2. The weight concentration Rw is the ratio of the weight of the plurality of inorganic particles 35 to the sum of the weight (W1) of the organic semiconductor contained in the organic semiconductor layer 30 and the weight (W2) of the plurality of inorganic particles 35 in a unit volume ( W2 / (W1 + W2)). The vertical axis in FIG. 7 is the detection rate EF1. In the example of FIG. 7, the thickness ratio ta is 0.33.

  As can be seen from FIG. 7, when the weight concentration Rw is high, the detection rate EF1 is high. When the weight concentration Rw is 0.8 or more, the increase in the detection rate EF1 is saturated.

  In the embodiment, the concentration (second weight concentration) of the plurality of inorganic particles 35 in the second region R2 is preferably 0.5 or more.

  In the embodiment, the average size of the plurality of inorganic particles 35 is preferably 10 nm or more and 10 μm or less. For example, backscattering of the radiation 81 can be effectively obtained. A high detection rate EF1 is easily obtained.

FIG. 8 is a graph illustrating characteristics of the radiation detector.
FIG. 8 shows an example of the result of X-ray diffraction (XRD) analysis of the organic semiconductor included in the organic semiconductor layer 30. The first to fourth samples SP01 to SP04 illustrated in FIG. 8 do not include the plurality of inorganic particles 35. These samples correspond to the characteristics of the first region R1. The first to third samples SP01 to SP03 are formed by a powder forming method. The thickness of each of these samples is 300 μm. The first sample SP01 includes F8T2 and PCBM. The second sample SP02 and the third sample SP03 include P3HT and PCBM. The second sample SP02 and the third sample SP03 are two samples containing the same material. The fourth sample SP04 is formed by a coating method. The thickness of the fourth sample SP04 is 20 μm. As already described, in the case of the coating method, it is difficult to form a thick layer uniformly. The fourth sample SP04 includes P3HT and PCBM.

  In FIG. 8, the horizontal axis represents the angle 2θ (°) in XRD. The vertical axis represents the signal intensity Int (cps) obtained. In FIG. 8, the first peak p1 is observed when the angle 2θ is in the range of 4 degrees to 7 degrees. The first peak p1 is derived from P3HT or PCBM. The second peak p2 is observed when the angle 2θ is in the range of 18 degrees to 22 degrees. The second peak p2 is derived from PCBM.

  As can be seen from FIG. 8, in the fourth sample SP04, the second peak p2 is not clear. In the fourth sample SP04, the intensity Int of the second peak p2 is less than ¼ of the intensity Int of the first peak p1.

  On the other hand, in the first to third samples SP01 to SP03, the second peak p2 is clear. Yes. In the fourth sample SP04, the intensity Int of the second peak p2 is ½ or more of the intensity Int of the first peak p1.

  Thus, in the organic semiconductor layer by the coating method, the second peak p2 derived from PCBM is not clear. In the organic semiconductor layer formed by the coating method, it is considered that the coating treatment affects the crystal characteristics in PCBM. On the other hand, in the organic semiconductor layer formed by the powder formation method, the second peak p2 derived from PCBM is clear. In the organic semiconductor layer formed by the powder forming method, it is considered that good crystal characteristics are maintained in PCBM.

  In the embodiment, for example, in the X-ray diffraction of the organic semiconductor layer 30, the intensity Int of the second peak p2 derived from the second semiconductor region is 1 / of the intensity Int of the first peak p1 derived from the first semiconductor region. 2 or more. The second semiconductor region includes, for example, PCBM. The first semiconductor region includes, for example, at least one selected from the group consisting of P3HT and PCBM.

  The first angle 2θ corresponding to the first peak p1 is not less than 4 degrees and not more than 7 degrees, for example. The second angle 2θ corresponding to the second peak p2 is, for example, not less than 18 degrees and not more than 22 degrees.

  Due to such characteristics in XRD, for example, a clear second peak p2 derived from the second semiconductor region (for example, PCBM) is obtained. Good crystallinity is obtained.

  Hereinafter, some examples of the manufacturing method of the radiation detector according to the embodiment will be described.

FIG. 9A and FIG. 9B are schematic cross-sectional views illustrating a method for manufacturing a radiation detector.
As shown in FIG. 9A, for example, the first conductive layer 10 is provided on the first base 51. For example, the first semiconductor region film Rf1 is formed on the first conductive layer 10. The first semiconductor region film Rf1 includes, for example, a solution containing the first organic semiconductor Sm1. The first semiconductor region film Rf1 may be formed by, for example, a coating method.

  As shown in FIG. 9B, the structure Rs2 is disposed on the first semiconductor region film Rf1. The structure Rs2 includes a second organic semiconductor Sm2 and a plurality of inorganic particles 35. By disposing the structure Rs2, the organic semiconductor layer 30 (see FIG. 1) is formed. The organic semiconductor layer 30 includes a first region R1 (see FIG. 1) formed from the first semiconductor region film Rf1 and a structure Rs2.

  The structure Rs2 is formed by, for example, a powder forming method. For example, the structure Rs2 includes a powder including the second organic semiconductor Sm2 and a powder including the plurality of inorganic particles 35. In this case, as shown in FIG. 9B, after the structure Rs2 is disposed, the pressure F1 is applied to the first semiconductor region film Rf1 and the structure Rs2. Thereby, the organic semiconductor layer 30 is obtained. If necessary, heating may be performed by applying the pressure F1. The second organic semiconductor Sm2 may be the same as or different from the first organic semiconductor Sm1.

FIG. 10A and FIG. 10B are schematic cross-sectional views illustrating a method for manufacturing a radiation detector.
As shown in FIG. 10A, for example, the first conductive layer 10 is provided on the first base 51. In this example, the organic semiconductor film 30 f is formed on the first conductive layer 10. The organic semiconductor film 30f may be a part of the first region R1 illustrated in FIG.

  As shown in FIG. 10B, the structure SB0 is prepared. The structure SB0 includes the organic semiconductor layer 30. The organic semiconductor layer 30 includes a first region R1 and a second region R2. The second region R2 includes a plurality of inorganic particles 35. The first region R1 does not include the plurality of inorganic particles 35. Alternatively, the first weight concentration of the plurality of inorganic particles 35 in the first region R1 is lower than the second weight concentration of the plurality of inorganic particles 35 in the second region R2.

  As shown in FIG. 10B, the structure SB0 is disposed on the first conductive layer 10. The structure SB0 is formed by, for example, a powder forming method. For example, the structure SB0 includes a powder that becomes the first region R1 and a powder that becomes the second region R2. As shown in FIG. 10B, a pressure F1 may be applied to the structure SB0. Thereby, the organic semiconductor layer 30 is obtained. If necessary, heating may be performed by applying the pressure F1.

  In this example, the organic semiconductor film 30f illustrated in FIG. 10A has improved adhesion strength between the first conductive layer 10 and the structural body SB0, for example. The organic semiconductor film 30f may function as an adhesive layer, for example.

FIG. 11A to FIG. 11C are schematic cross-sectional views illustrating a method for manufacturing a radiation detector.
As shown in FIG. 11A, for example, the first conductive layer 10 is provided on the first base 51. For example, the first region layer Rs1 is formed on the first conductive layer 10. The first region layer Rs1 includes a first organic semiconductor Sm1.

  As shown in FIG. 11B, for example, the powder layer Rp2 is formed on the first region layer Rs1. The powder layer Rp2 includes a semiconductor powder to be the second organic semiconductor Sm2 and a plurality of inorganic particles 35.

  As shown in FIG. 11C, the pressure F1 is applied to the powder layer Rp2 to form the second region R2. The second region R2 includes the second organic semiconductor Sm2 and a plurality of inorganic particles 35. On the other hand, the first region R1 is formed from the first region layer Rs1. The organic semiconductor layer 30 is formed from the first region R1 and the second region R2. If necessary, heating may be performed by applying the pressure F1. The second organic semiconductor Sm2 may be the same as or different from the first organic semiconductor Sm1.

(Second Embodiment)
FIG. 12 is a schematic cross-sectional view illustrating a radiation detector according to the second embodiment.
As shown in FIG. 12, the radiation detector 110a according to the second embodiment includes an intermediate layer (in this example, the first intermediate layer 41 in addition to the first conductive layer 10, the second conductive layer 20, and the organic semiconductor layer 30). And a second intermediate layer 42). The configuration of the radiation detector 110a other than the intermediate layer is the same as the configuration of the radiation detector 110. Hereinafter, examples of the intermediate layer will be described.

  The first intermediate layer 41 is provided between the first conductive layer 10 and the organic semiconductor layer 30. The second intermediate layer 42 is provided between the second conductive layer 20 and the organic semiconductor layer 30.

  The first intermediate layer 41 includes, for example, an electron donating organic material. The electron donating organic material includes, for example, Poly-NPD. The thickness of the first intermediate layer 41 is, for example, not less than 10 nm and not more than 100 nm.

  For example, the first intermediate layer 41 may function as an electron blocking film. For example, when a bias voltage is applied, the first intermediate layer 41 suppresses injection of electrons from the second conductive layer 20 into the organic semiconductor layer 30. For example, dark current is suppressed.

  The second intermediate layer 42 includes, for example, an electron accepting material. The electron-accepting material includes, for example, at least one selected from the group consisting of BCP and NBPhne. The thickness of the second intermediate layer 42 is, for example, not less than 10 nm and not more than 100 nm.

  For example, the second intermediate layer 42 may function as a hole blocking film. The organic layer b suppresses injection of holes from the first conductive layer 10 into the organic semiconductor layer 30 when, for example, a bias voltage is applied. For example, dark current is suppressed.

  By providing the organic film 35, for example, dark current can be suppressed. High sensitivity is obtained.

  FIG. 13 is a schematic cross-sectional view illustrating a part of the radiation detector according to the second embodiment.

  FIG. 13 schematically shows a region including the second surface 30 b of the organic semiconductor layer 30. As shown in FIG. 13, the second surface 30b is provided with irregularities 30dp. The organic semiconductor layer 30 includes a surface (second surface 30 b) that faces the second conductive layer 20. The second surface 30 b corresponds to the second intermediate layer 42. At least a part of the second intermediate layer 42 is provided in the recess of the unevenness 30 dp. For example, the contact area between the organic semiconductor layer 30 and the second intermediate layer 42 is increased. For example, sensitivity is improved.

Hereinafter, an example of the organic semiconductor layer 30 in the embodiment will be described.
FIG. 14 is a schematic cross-sectional view illustrating a part of the radiation detector according to the embodiment.
As shown in FIG. 14, the organic semiconductor layer 30 includes a first semiconductor region 31 and a second semiconductor region 32. These areas are intermingled. For example, the organic semiconductor layer 30 may have a bulk heterojunction structure.

  The first semiconductor region 31 may include, for example, at least one selected from the group consisting of P3HT, F8T2, F8BT, and PVK.

The second semiconductor region 32 may include, for example, at least one selected from the group consisting of PC ₆₁ BM, PC ₇₁ BM, SubPC, and SubNC.

  The first conductive layer 10 may include, for example, a metal oxide. The first conductive layer 10 may include, for example, ITO.

  The second conductive layer 20 includes, for example, a metal. For example, the metal may include at least one selected from the group consisting of Al, Ag, and Au.

FIG. 15 is a circuit diagram illustrating a part of the radiation detector according to the embodiment.
FIG. 15 illustrates a charge amplifier 75 provided in the detection circuit 70. The first wiring 71 (that is, the first conductive layer 10) is electrically connected to one of the two input terminals of the charge amplifier 75. The second wiring 72 (that is, the second conductive layer 20) is electrically connected to the other of the two input terminals of the charge amplifier 75. A capacitance 76 is connected between the negative input of the charge amplifier 75 and the output terminal of the charge amplifier 75. For example, a voltage corresponding to the electric charge generated between the first conductive layer 10 and the second conductive layer 20 is obtained as the output signal OS.

  In the charge amplifier 75, a resistor may be provided in parallel with the capacitance 76. An input terminal for a reference voltage may be further provided.

FIG. 16 is a schematic cross-sectional view illustrating a radiation detector according to the embodiment.
As shown in FIG. 16, the radiation detector 111 according to the embodiment further includes a sealing member 60 in addition to the first conductive layer 10, the second conductive layer 20, the organic semiconductor layer 30, and the first base 51. It is done. For the first base 51 and the sealing member 60, for example, glass is used. The outer edge of the sealing member 60 is joined to the outer edge of the first base 51. In the space surrounded by the first base 51 and the sealing member 60, the first conductive layer 10, the second conductive layer 20, and the organic semiconductor layer 30 are provided. The first conductive layer 10, the second conductive layer 20, and the organic semiconductor layer 30 are hermetically sealed by the first base 51 and the sealing member 60. This makes it easier to obtain stable characteristics. High reliability is obtained.

  A space 65 is provided between the first conductive layer 10, the second conductive layer 20, the organic semiconductor layer 30, and the sealing member 60. For example, an inert gas (for example, nitrogen gas) is sealed in the space 65.

FIG. 17 is a schematic cross-sectional view illustrating the radiation detector according to the embodiment.
As shown in FIG. 17, the radiation detector 120 is provided with a plurality of first conductive layers 10. The plurality of first conductive layers 10 are along a plane (for example, an XY plane) that intersects a first direction (Z-axis direction) from one of the plurality of first conductive layers 10 toward the second conductive layer 20. Lined up. The XY plane is perpendicular to the Z-axis direction. The plurality of first conductive layers 10 are arranged, for example, along the X-axis direction and the Y-axis direction. The plurality of first conductive layers 10 are arranged in a matrix, for example.

  In the radiation detector 120, for example, an image corresponding to the radiation 81 is obtained. In the radiation detector 120, the configuration described in the first embodiment and the second embodiment and the modifications thereof can be applied. The radiation detector 120 can also provide a radiation detector that can improve the detection efficiency.

  According to the embodiment, it is possible to provide a radiation detector capable of improving detection efficiency and a method for manufacturing the same.

  In this specification, the state of being electrically connected includes the state where two conductors are in direct contact. The state of being electrically connected includes a state in which two conductors are connected by another conductor (for example, a wiring). The electrically connected state includes a state in which a switching element (a transistor or the like) is provided between the paths between the two conductors, and a state in which a current flows in the path between the two conductors can be formed.

  In the present specification, “vertical” and “parallel” include not only strict vertical and strict parallel, but also include variations in the manufacturing process, for example, and may be substantially vertical and substantially parallel. .

  The embodiments of the present invention have been described above with reference to specific examples. However, the present invention is not limited to these specific examples. For example, regarding a specific configuration of each element included in the radiation detector, such as a conductive layer, an organic semiconductor layer, and inorganic particles, the person skilled in the art appropriately implements the present invention by appropriately selecting from a known range, As long as the same effect can be obtained, it is included in the scope of the present invention.

  Moreover, what combined any two or more elements of each specific example in the technically possible range is also included in the scope of the present invention as long as the gist of the present invention is included.

  In addition, all radiation detectors and methods for manufacturing the same that can be implemented by those skilled in the art based on the radiation detectors and methods for manufacturing the same described above as embodiments of the present invention also include the gist of the present invention. As long as it is included, it belongs to the scope of the present invention.

  In addition, in the category of the idea of the present invention, those skilled in the art can conceive of various changes and modifications, and it is understood that these changes and modifications also belong to the scope of the present invention. .

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

  2θ: Angle, 10: First conductive layer, 20: Second conductive layer, 30: Organic semiconductor layer, 30f: Organic semiconductor film, 31: First semiconductor region, 32: Second semiconductor region, 35: Inorganic particles, 41 , 42 ... first and second intermediate layers 51, 52 ... first second substrate, 60 ... sealing member, 65 ... space, 70 ... detection circuit, 71 ... first wiring, 72 ... second wiring, 75 ... Charge amplifier, 76 ... capacitance, 81 ... radiation, 110, 111, 120 ... radiation detector, C0 ... concentration, Cp ... peak concentration, Cp / 2 ... concentration, EF1 ... detection rate, F1 ... pressure, Int ... intensity, OS ... output signal, R1, R2 ... first and second regions, Rf1 ... first semiconductor region film, Rs1 ... first region layer, Rp2 ... powder layer, Rs2 ... structure, Rw ... weight concentration, SB0 ... structure, SP0 ... properties, SP01～SP04 ... first to fourth samples, Sm1, Sm2 ... first, second organic semiconductor, t1, t2 ... first, second thickness, ta ... ratio

Claims (10)

A first conductive layer;
A second conductive layer;
An organic semiconductor layer provided between the first conductive layer and the second conductive layer, wherein the organic semiconductor layer includes a first region and a second region, and the second region is the first region. Provided between a region and the second conductive layer, wherein the second region includes a plurality of inorganic particles, and the first region does not include the plurality of inorganic particles or the plurality of inorganic particles in the first region. A first weight concentration of the organic semiconductor layer is lower than a second weight concentration of the plurality of inorganic particles in the second region;
Radiation detector equipped with.   The radiation detector according to claim 1, wherein a thickness of the first region is larger than a thickness of the second region. The radiation detector according to claim 1, wherein the plurality of inorganic particles include at least one selected from the group consisting of Bi ₂ O ₃ and ZnO. The organic semiconductor layer includes a first surface facing the first conductive layer, and a second surface facing the second conductive layer,
The radiation detector according to claim 1, wherein the unevenness of the second surface is larger than the unevenness of the first surface. The organic semiconductor layer includes a surface facing the second conductive layer,
The surface has irregularities;
4. The radiation detector according to claim 1, wherein at least a part of the second conductive layer is provided in the concave portion of the unevenness. An intermediate layer provided between the second conductive layer and the organic semiconductor layer;
The organic semiconductor layer includes a surface facing the second conductive layer,
The surface has irregularities;
The radiation detector according to claim 1, wherein at least a part of the intermediate layer is provided in the concave portion of the unevenness. The organic semiconductor layer includes a polymer first semiconductor region and a low-molecular second semiconductor region,
The first semiconductor region is of a first conductivity type;
The radiation detector according to claim 1, wherein the second semiconductor region has a second conductivity type. Forming a first semiconductor region film containing a solution containing a first organic semiconductor;
A structure including a second organic semiconductor and a plurality of inorganic particles is disposed on the first semiconductor region film, and includes a first region formed from the first semiconductor region film and the structure. A method for manufacturing a radiation detector, wherein an organic semiconductor layer is formed. A structure including the organic semiconductor layer is prepared, the organic semiconductor layer includes a first region and a second region, the second region includes a plurality of inorganic particles, and the first region includes the plurality of inorganic particles. Or a first weight concentration of the plurality of inorganic particles in the first region is lower than a second weight concentration of the plurality of inorganic particles in the second region,
A method for manufacturing a radiation detector, wherein the structure is disposed on a first conductive layer. Forming a first region layer including a first organic semiconductor;
A powder layer including a semiconductor powder to be a second organic semiconductor and a plurality of inorganic particles is formed on the first region layer, a pressure is applied to the powder layer, and the second organic semiconductor and A manufacturing method of a radiation detector which forms the 2nd field containing a plurality of above-mentioned inorganic particles.