A nuclear detection device capable of outputting optical signals and built-in gain and an imaging device

Abstract

The application provides a nuclear detection device and an imaging device which can output light signals and have built-in gain, and mainly solves the technical problem that the existing imaging devices mostly use scintillator materials to convert radiation into light through the characteristics of the scintillator materials; however, the scintillator materials have the defects of low energy resolution, narrow linear range, and poor radiation resistance stability, thereby leading to poor imaging effect of the imaging device. The application comprises a bipolar transistor nuclear detector for converting radiation energy into electric energy and generating electric gain, and an LED light emitter for converting electric energy into light signals; the bipolar transistor nuclear detector comprises a collector, a base, an emitter, and a bottom electrode; the LED light emitter comprises an electron transport layer, an active light-emitting layer, a hole transport layer, a hole injection layer, and a top electrode which are connected in sequence; and the side of the electron transport layer, which is far away from the active light-emitting layer, is connected with the collector.

Description

TECHNICAL FIELD

[0001] The present application relates to a nuclear detection device and an imaging device, in particular to a nuclear detection device capable of outputting light signals and built-in gain and an imaging device using the same. BACKGROUND

[0002] Charged particle / ray imaging devices have a wide range of applications in industrial and medical non-destructive imaging detection, and play an extremely important role in experimental research of high-energy physics, heavy ion physics, nuclear physics and atomic and molecular physics; the principle is to convert radiation rays into light or electricity by arraying a plurality of nuclear detection devices, wherein one nuclear detection device serves as a pixel point corresponding to different gray values, thereby realizing imaging.

[0003] Most of the nuclear detection devices in existing imaging devices use scintillators to convert nuclear radiation into light through the material properties of the scintillators, but due to the low energy resolution, narrow linear range and poor radiation resistance stability of the scintillators, the light-emitting effect of the nuclear detection device is poor, which further leads to poor imaging effect of the imaging device. SUMMARY

[0004] The purpose of the present application is to solve the technical problem that most of the nuclear detection devices in existing imaging devices use scintillators to convert nuclear radiation into light through the material properties of the scintillators, but due to the low energy resolution, narrow linear range and poor radiation resistance stability of the scintillators, the light-emitting effect of the nuclear detection device is poor, which further leads to poor imaging effect of the imaging device, and to provide a nuclear detection device capable of outputting light signals and built-in gain and an imaging device using the same.

[0005] To achieve the above-mentioned purpose, the technical solution adopted by the present application is as follows:

[0006] A nuclear detection device capable of outputting light signals and built-in gain, characterized in that:

[0007] It comprises a bipolar transistor nuclear detector for converting radiation energy into electrical energy and generating electrical gain, and an LED light emitter for converting electrical energy into light signals.

[0008] The bipolar transistor nuclear detector comprises a collector, a base, an emitter and a bottom electrode.

[0009] One side of the collector is defined as the front side, and the other side is defined as the back side.

[0010] The collector is provided with a first mounting cavity near the front side, and the base is arranged in the first mounting cavity; the base is provided with a second mounting cavity near the front side, and the emitter is arranged in the second mounting cavity; and the bottom electrode is arranged on the surface of the front side of the emitter.

[0011] The LED light-emitting device comprises an electron transport layer, an active light-emitting layer, a hole transport layer, a hole injection layer and a top electrode connected in sequence.

[0012] The side of the electron transport layer far from the active light-emitting layer is connected with the surface of the front side of the collector, and is arranged adjacent to the bottom electrode.

[0013] Further, the emitter adopts a high-doped-concentration n-type emitter; the base adopts a low-doped-concentration p-type base; and the collector adopts a super-low-doped-concentration n-type collector.

[0014] The doped concentration is greater than or equal to 10 18 cm -3 The doped concentration is 10 16 cm -3 -10 17 cm -3 The doped concentration is less than or equal to 10 15 cm -3 The doped concentration is super low.

[0015] Further, the doped concentration of the emitter is 10 19 cm -3 , the doped concentration of the base is 10 16 cm -3 , and the doped concentration of the collector is 10 14 cm -3 .

[0016] Further, the thickness of the base is 0.3um-0.5um, and the thickness of the collector is 5um-10um.

[0017] Further, the collector adopts a wide-bandgap semiconductor material.

[0018] Further, the active light-emitting layer adopts a double-heterojunction structure or a quantum well structure.

[0019] Further, the wide-bandgap semiconductor material is gallium nitride or silicon carbide.

[0020] The double-heterojunction structure is AlGaAs / GaAs / AlGaAs, and the quantum well structure is InGaAs / GaAs / AlGaAs.

[0021] Further, the hole injection layer adopts a high-doped-concentration P-type material, and the top electrode adopts a transparent electrode ITO electrode.

[0022] Meanwhile, the application also provides an imaging device comprising a plurality of nuclear detection devices arranged in an n*n array, and the special feature is that:

[0023] The nuclear detection device is a nuclear detection device capable of outputting an optical signal and built-in gain.

[0024] Compared with the prior art, the nuclear detection device has the following advantages:

[0025] 1. The bipolar transistor nuclear detector can convert nuclear radiation into electrical energy, and the electrical energy can be amplified to increase the output current. The electron transport layer of the LED light emitter is directly connected to the collector of the bipolar transistor nuclear detector, so that the current output by the bipolar transistor nuclear detector can be transmitted to the active light-emitting layer in the LED light emitter, and the electrical energy can be efficiently converted into an optical signal. The nuclear detection device has the advantages of newness, gain effect, and realization of the nuclear-optical conversion process. Compared with the existing nuclear detection device that realizes the nuclear-optical conversion process through a scintillator material, the nuclear detection device has the advantages of high energy resolution, wide linear range, and strong radiation resistance.

[0026] 2. The emitter is an n-type emitter with high doping concentration, the base is a p-type base with low doping concentration, and the collector is an n-type collector with ultra-low concentration, so that the amplification effect of the current can be improved, thereby improving the imaging effect by enhancing the current gain.

[0027] 3. The collector is a wide-bandgap semiconductor material, which can reduce the dark current and meet the high-voltage requirement.

[0028] 4. The active light-emitting layer has a double-heterojunction structure or a quantum well structure, which can improve the internal quantum efficiency and light intensity of the LED light emitter, thereby improving the imaging effect.

[0029] 5. The nuclear detector capable of outputting an optical signal and built-in gain is arranged in an n*n array, which has better imaging effect than the prior art, and realizes the ray imaging in a simple and easy way. DETAILED DESCRIPTION

[0030] Figure 1 is a structure schematic view of the nuclear detection device capable of outputting an optical signal and built-in gain according to the present application;

[0031] Figure 2 is a structure schematic view of the imaging device according to the present application.

[0032] In the drawings:

[0033] 1-bipolar transistor nuclear detector, 11-collector, 12-base, 13-emitter, 14-bottom electrode;

[0034] 2 - LED light emitter, 21 - electron transport layer, 22 - active light emitting layer, 23 - hole transport layer, 24 - hole injection layer, 25 - top electrode;

[0035] 3 - nuclear detection device. DETAILED DESCRIPTION

[0036] In order to make the objects, advantages and features of the present application clearer, the following will further describe a nuclear detection device capable of outputting light signals and built-in gain and an imaging device according to the present application in conjunction with the accompanying drawings and specific embodiments. The advantages and features of the present application will be clearer according to the following specific embodiments. It should be noted that the drawings are all in a very simplified form and all use non-precise proportions, only for the purpose of facilitating and clearly assisting the description of the embodiments of the present application; secondly, the structures shown in the drawings are often part of the actual structures.

[0037] As shown in Figure 1 , the nuclear detection device capable of outputting light signals and built-in gain according to the present application comprises a bipolar transistor nuclear detector 1 for converting radiation energy into electrical energy and capable of generating electrical gain, and an LED light emitter 2 for converting electrical energy into light signals.

[0038] The bipolar transistor nuclear detector 1 comprises a collector 11, a base 12, an emitter 13 and a bottom electrode 14; one side of the collector 11 is defined as the front side and the other side is defined as the back side; a first mounting cavity is arranged at the position of the collector 11 close to the front side, and the base 12 is arranged in the first mounting cavity; a second mounting cavity is arranged at the position of the base 12 close to the front side, and the emitter 13 is arranged in the second mounting cavity; the bottom electrode 14 is arranged on the surface of the emitter 13 close to the front side; in order to achieve current gain, the emitter 13 adopts a high-doped n-type emitter; the base 12 adopts a low-doped p-type base, and at the same time, the base 12 should be as narrow as possible, much smaller than the diffusion length of the carrier, so in this embodiment, the thickness of the base 12 ranges from 0.3um to 0.5um; the collector 11 adopts a super-low-doped n-type collector, and in order to achieve the function of nuclear detection, the collector 11 should be as thick as possible, and in this embodiment, the thickness of the collector 11 is selected to range from 5um to 10um; at the same time, in order to reduce the dark current and bear high voltage, the collector 11 can adopt a wide-bandgap semiconductor material, such as gallium nitride or silicon carbide, etc.; the doping concentration ≥10 19 cm -3 is high-doped; the doping concentration 10 16 cm -3 -10 17 cm -3 is medium-doped; the doping concentration ≤10 15 cm -3With a low doping concentration, the collector 11 and base 12 form a reverse-biased collector-base junction as a radiation-sensitive region. When radiation (X-rays, etc.) irradiates the collector-base junction, a large number of non-equilibrium carriers are generated in the collector-base junction. The generated holes flow to the base 12, increasing the base potential, and causing a large number of electrons to be injected into the base 12 from the forward-biased emitter-base junction. Except for a small number that recombine with holes in the base 12, most of them pass through the base 12 to reach the collector 11, thereby generating a current amplification effect and realizing electrical gain.

[0039] In a preferred embodiment of the present invention, the doping concentration of the emitter 13 is selected to be 10. 19 cm -3 The doping concentration of base 12 is rotated to 10. 16 cm -3 The doping concentration of collector 11 is selected as 10. 14 cm -3 .

[0040] In a preferred embodiment of the present invention, the base 12 has a thickness of 0.3 μm and the emitter 13 has a thickness of 10 μm.

[0041] The LED emitter 2 includes an electron transport layer 21, an active light-emitting layer 22, a hole transport layer 23, a hole injection layer 24, and a top electrode 25 connected in sequence. The hole injection layer 24 is made of a highly doped P-type material. The surface of the electron transport layer 21 away from the active light-emitting layer 22 is connected to the surface of the collector 11 near the front side, and is used to transmit the current output by the collector 11. The electron transport layer 21 is disposed adjacent to the bottom electrode 14. The collector 11 serves as the electron injection layer of the LED emitter 2. Electrons amplified by the electron transport layer 21 enter the active light-emitting layer 22. At the same time, holes injected by the top electrode 25 are also transported to the active light-emitting layer 22. Electrons and holes recombine in the active light-emitting layer 22 and emit light signals.

[0042] In order to improve the internal quantum efficiency and luminous intensity of the LED, in a preferred embodiment of the present invention, the active light-emitting layer 22 adopts a double heterojunction structure, such as AlGaAs / GaAs / AlGaAs; or adopts a quantum trap structure, such as InGaAs / GaAs / AlGaAs.

[0043] To facilitate light emission, the top electrode 25 is a transparent ITO electrode.

[0044] like Figure 2The imaging device comprises a plurality of nuclear detection devices 3 arranged in an n*n array, and the nuclear detection device 3 is a nuclear detection device capable of outputting an optical signal. In the present application, the light emission intensity of each nuclear detection device is positively correlated with the carrier injected by the nuclear detection device, and the carrier concentration collected by the nuclear detection device is related to the radiation intensity. When the rays are irradiated, different degrees of intensity attenuation will occur when the rays pass through different substances, and when the rays reach the plurality of nuclear detection devices in the array, each nuclear detection device on the array acts as a pixel point and responds to rays with different intensities. Through the electro-optical coupling working process of the nuclear detection device, the response is released in the form of visible light, thereby realizing the imaging function.

Claims

1. A nuclear detection device capable of outputting optical signals and having built-in gain, characterized in that: It includes a bipolar transistor nuclear detector (1) for converting radiant energy into electrical energy and generating electrical gain, and an LED emitter (2) for converting electrical energy into optical signals; The bipolar transistor nuclear detector (1) includes a collector (11), a base (12), an emitter (13), and a bottom electrode (14); Define one side of the collector (11) as the front side and the other side as the rear side; The collector (11) has a first mounting cavity near its front side, and the base (12) is disposed in the first mounting cavity; the base (12) has a second mounting cavity near its front side, and the emitter (13) is disposed in the second mounting cavity; the bottom electrode (14) is disposed on the surface in front of the emitter (13); The LED emitter (2) includes an electron transport layer (21), an active light-emitting layer (22), a hole transport layer (23), a hole injection layer (24), and a top electrode (25) connected in sequence. The side of the electron transport layer (21) away from the active light-emitting layer (22) is connected to the surface in front of the collector electrode (11) and is disposed adjacent to the bottom electrode (14).

2. The nuclear detection device capable of outputting optical signals and having built-in gain according to claim 1, characterized in that: The emitter (13) is a highly doped n-type emitter; the base (12) is a low-doped p-type base; and the collector (11) is an ultra-low doped n-type collector. Doping concentration ≥10 18 cm -3 High doping concentration; doping concentration 10 16 cm -3 -10 17 cm -3 Low doping concentration; doping concentration ≤ 10 15 cm -3 It has an ultra-low doping concentration.

3. A nuclear detection device capable of outputting optical signals and having built-in gain according to claim 2, characterized in that: The emitter (13) has a doping concentration of 10. 19 cm -3 The doping concentration of the base (12) is 10. 16 cm -3 The doping concentration of the collector (11) is 10. 14 cm -3 .

4. A nuclear detection device capable of outputting optical signals and having built-in gain according to claim 3, characterized in that: The thickness of the base (12) is 0.3um-0.5um; the thickness of the collector (11) is 5um-10um.

5. A nuclear detection device capable of outputting optical signals and having built-in gain according to claim 4, characterized in that: The collector (11) is made of a wide-bandgap semiconductor material.

6. A nuclear detection device capable of outputting optical signals and having built-in gain according to claim 5, characterized in that: The active light-emitting layer (22) adopts a double heterojunction structure; or a quantum trap structure.

7. A nuclear detection device capable of outputting optical signals and having built-in gain according to claim 6, characterized in that: The wide-bandgap semiconductor material is gallium nitride or silicon carbide; The structure of the double heterojunction is AlGaAs / GaAs / AlGaAs; the structure of the quantum trap is InGaAs / GaAs / AlGaAs.

8. A nuclear detection device capable of outputting optical signals and having built-in gain according to claim 7, characterized in that: The hole injection layer (24) is made of a highly doped P-type material; the top electrode (25) is a transparent ITO electrode.

9. An imaging device comprising multiple nuclear detection devices (3) arranged in an n×n array, characterized in that: The nuclear detection device (3) is a nuclear detection device that can output optical signals and has built-in gain as described in any one of claims 1-8.

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