Amorphous pbogal2o3 composite material, preparation method thereof and x-ray detector

Abstract

The present application relates to amorphous PbO / Ga2O3 composite material and its preparation method and X-ray detector, belong to metal oxide photoelectric function block material field. Amorphous PbO / Ga2O3 composite material, its molecular formula is (PbO) x (Ga2O3) 1‑x , 0.6≤x<0.8. The PbO / Ga2O3 composite material prepared by the present application is amorphous, stable in nature, has strong X-ray absorption capacity, low dark current density and high photoelectric response.

Description

TECHNICAL FIELD

[0001] The present application relates to amorphous PbO / Ga2O3 composite material and its preparation method and X-ray detector, belonging to the field of metal oxide photoelectric functional bulk material. BACKGROUND

[0002] As an important part of modern non-destructive detection equipment, X-ray detector has the characteristics of digital imaging, high resolution, wide dynamic range, etc., and is widely used in medical, non-destructive testing, safety inspection and other fields. Silicon, as a traditional X-ray detector material, plays an important role in many fields. Si-PIN radiation detector can be used for high-energy physics experiments and X-ray spectrum detection; silicon photodiode can be combined with thin film transistor (TFT) to form a highly integrated silicon X-ray detector. However, the atomic number of silicon is small, and the absorption capacity of X-ray is weak. Cadmium telluride, cadmium zinc telluride detector has low dark current, high resistivity, good detection efficiency and high energy resolution, and is widely used in non-destructive testing and safety monitoring. In the process of preparing cadmium telluride, cadmium zinc telluride detector, the surface is easy to be damaged, which leads to the reduction of X-ray detection performance. In addition, cadmium is a highly toxic substance, which can accumulate in the food chain like mercury, which is contrary to the concept of environmental friendliness, safety and non-toxicity. Amorphous selenium is a kind of high-stability photoelectric material, which is widely used in medical imaging. However, the stability of amorphous selenium needs to be improved, and it is easy to crystallize at high temperature, which leads to the reduction of resistivity of the detection unit and the reduction of the performance of the device. In addition, the atomic number of selenium is small, which is more suitable for the detection of low-energy X-rays. In recent years, organic lead iodine (bromine) perovskite has become a star material in photodetectors due to its mild synthesis conditions and simple process. Elements with high atomic number, such as lead and iodine, have high absorption rates for X-rays. The difficulty lies in that this material contains organic components, and is mostly prepared by solution method. The stability of the structure and performance of the material and the whole detector is a key consideration factor in application, especially the destructive effect of high-energy X-ray photon irradiation on the material. The all-inorganic perovskite material does not contain organic components, which can effectively overcome the instability of organic lead iodine (bromine) perovskite. However, defects cannot be avoided in the preparation and operation process of inorganic perovskite thin film, and these defects will become non-radiation recombination centers, which is not conducive to the performance of the detector. There is also a problem in the preparation of X-ray detector from polycrystalline material, which is that the scattering of photo-generated carriers is strong at the interface of the material, which easily causes charge transmission loss and reduces the utilization rate of photon signal, thereby reducing the photoelectric response of the detector.

[0003] CN 202110894526.9 discloses an X-ray detector, which sequentially repeats the deposition of PbO layer and Ga2O3 layer between the top electrode and the bottom electrode. First, the photoelectric functional layer prepared by the patent is a polycrystalline structure; second, the functional layer is a thin film layer, and the preparation of the thin film layer needs to use the method of vacuum physical vapor deposition, which involves a relatively complex device; in addition, thin films are mainly used for the development of large-area detectors, while bulk materials are mainly used for the development of small-size devices, because the thickness of the bulk material is larger, it can also be used for high-energy rays, while the thin film is difficult to achieve.

[0004] Therefore, it has become an urgent problem to prepare an amorphous structure bulk material photoelectric functional layer material. SUMMARY

[0005] The first technical problem to be solved by the present application is to provide a new photoelectric functional layer material for photoconductive X-ray detectors, which has the properties of amorphous state, stability, strong X-ray absorption ability, low dark current density and high photoelectric response.

[0006] The amorphous PbO / Ga2O3 composite material has a molecular formula of (PbO) x (Ga2O3) 1-x , and 0.6≤x<0.8.

[0007] In specific embodiments, x=0.698, 0.747, 0.761 or 0.789.

[0008] The second technical problem to be solved by the present application is to provide a preparation method of the amorphous PbO / Ga2O3 composite material.

[0009] The preparation method of the amorphous PbO / Ga2O3 composite material comprises the following steps:

[0010] In one embodiment, the preparation method of the amorphous PbO / Ga2O3 composite material comprises the following steps:

[0011] a. Take PbO and Ga2O3, and place them at 1000-1200℃ for heat preservation until the PbO and Ga2O3 are completely melted into a melt; preferably, place them at 1050℃; more preferably, the heat preservation time is 15 min;

[0012] b. Pour the melt on a metal plate after mixing, and cool it in air to obtain the amorphous PbO / Ga2O3 composite material; preferably, the metal plate is a nickel plate.

[0013] In one embodiment, the amorphous PbO / Ga2O3 composite material is placed in 300-350℃ for 20-36h; preferably, placed in 350℃ for 24h.

[0014] The application also provides an X-ray detector.

[0015] The X-ray detector comprises, from bottom to top, a substrate, a bottom electrode, an amorphous (PbO) x (Ga2O3) 1-x bulk and a top electrode;

[0016] The bottom electrode is deposited on the bottom surface of the amorphous (PbO) x (Ga2O3) 1-x bulk; the top electrode is deposited on the upper surface of the amorphous (PbO) x (Ga2O3) 1-x bulk; the amorphous (PbO) x (Ga2O3) 1-x bulk is obtained by cutting and polishing the amorphous PbO / Ga2O3 composite material.

[0017] In one embodiment, the amorphous (PbO) x (Ga2O3) 1-x bulk has a thickness of 600-1700μm, preferably a thickness of 600-860μm;

[0018] In one embodiment, the thickness of the bottom electrode and the top electrode is 20-50nm, preferably the thickness of the bottom electrode and the top electrode is 30nm respectively.

[0019] In one embodiment, the polishing method of the amorphous PbO / Ga2O3 composite material is: polishing with 1000 mesh, 2000 mesh, 7000 mesh sandpaper and diamond polishing gel in sequence.

[0020] In one embodiment, the electrode material of the top electrode and the bottom electrode is one or a combination of two or more of Au, Ti, Ni, ITO, Al, Cr, conductive carbon paste, conductive silver paste, carbon nanotube, graphene and conductive copper foil; preferably, the electrode material of the bottom electrode and the top electrode is Au;

[0021] In one embodiment, the substrate is a glass substrate or a ceramic substrate.

[0022] In one embodiment, in the X-ray detector, the area of the bottom electrode ranges from 0.1mm2 to 10mm2, preferably from 0.5mm2 to 5mm2. x (Ga2O3) 1-xThe entire bottom surface of the bulk; the top electrode is a single electrode or an array electrode; when the top electrode is a single electrode, the area range is amorphous (PbO) x (Ga2O3) 1-x The entire upper surface of the bulk; when the top electrode is an array electrode, the top electrode is prepared into an m*n array electrode through an m*n mask, wherein m>=2, n>=2; preferably, m=3, n=3.

[0023] The amorphous (PbO) x (Ga2O3) 1-x The bulk, the X-ray detector and the preparation method have the following beneficial effects:

[0024] (1) The preparation process is simple, and the amorphous (PbO) x (Ga2O3) 1-x Bulk can be directly prepared by a high-temperature melting quenching method.

[0025] (2) The amorphous (PbO) x (Ga2O3) 1-x Bulk realizes strong absorption of X-ray photons and achieves an ultra-low dark current density (1.1 pA / cm 2 ).

[0026] (3) The amorphous (PbO) x (Ga2O3) 1-x Bulk X-ray detector has a high photocurrent density, a high signal-to-noise ratio (SNR=800), and a sensitivity (S=2.82 uC / Gy / cm 2 )

[0027] (4) The (PbO) x (Ga2O3) 1-x Material prepared by the present application is amorphous, and there is no grain boundary interface in the amorphous material, so that there is no interface scattering of photo-generated carriers, and the effective transport of charges in the material can be ensured. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 The amorphous (PbO) x (Ga2O3) 1-x Bulk single-electrode detector structure;

[0029] Figure 2 The amorphous (PbO) x (Ga2O3) 1-x Bulk array electrode detector structure;

[0030] Figure 1 、 Figure 2In the figure, 100 - substrate; 101 - bottom electrode; 102 - amorphous (PbO) x (Ga2O3) 1-x layer; 103 - top electrode; 104 - encapsulation glue; 105 - silver wire; 106 - silver wire;

[0031] Figure 3 amorphous (PbO) x (Ga2O3) 1-x Preparation flow of bulk X-ray detector;

[0032] Figure 4 amorphous (PbO) x (Ga2O3) 1-x X-ray diffraction pattern of bulk; wherein x is 0.789, 0.761, 0.747, 0.698;

[0033] Figure 5 amorphous (PbO) x (Ga2O3) 1-x Surface scanning electron microscope image of bulk; wherein x is 0.789, 0.761, 0.747, 0.698;

[0034] Figure 6 amorphous (PbO) x (Ga2O3) 1-x Cross-sectional scanning electron microscope image of bulk; wherein x is 0.789, 0.761, 0.747, 0.698;

[0035] Figure 7 Relationship between absorption thickness and absorption coefficient;

[0036] Figure 8 amorphous (PbO) x (Ga2O3) 1-x Dark current density of bulk;

[0037] Figure 9 amorphous (PbO) x (Ga2O3) 1-x Photocurrent density of bulk;

[0038] Figure 10 amorphous (PbO) x (Ga2O3) 1-x Signal-to-noise ratio of bulk X-ray detector;

[0039] Figure 11 amorphous (PbO) x (Ga2O3) 1-x Sensitivity of bulk X-ray detector;

[0040] Figure 12amorphous (PbO) 0.789 (Ga2O3) 0.211 Dark, photocurrent of bulk X-ray detector array;

[0041] Figure 13 amorphous (PbO) 0.789 (Ga2O3) 0.211 Uniformity of bulk X-ray detector array. DETAILED DESCRIPTION

[0042] The amorphous PbO / Ga2O3 composite material has a molecular formula of (PbO) x (Ga2O3) 1-x , 0.6≤x<0.8.

[0043] The material of the present application is amorphous, has no internal interface, and has weak scattering of photo-generated carriers; in addition, the composition contains lead and gallium, two high-atomic-number elements, which have strong absorption of X-rays.

[0044] The value range of x of the present application is: 0.6≤x<0.8. When x<0.6, the prepared material is a polycrystalline material, not an amorphous material; when x≥0.8, PbO will be precipitated in the prepared material, resulting in a decrease in the mass of Pb in the bulk material, affecting the performance of the material.

[0045] In a specific embodiment, x=0.698, 0.747, 0.761 or 0.789.

[0046] The second technical problem solved by the present application is to provide a preparation method of the amorphous PbO / Ga2O3 composite material.

[0047] The preparation method of the amorphous PbO / Ga2O3 composite material comprises: taking PbO and Ga2O3, and using a melt quenching method to prepare the amorphous PbO / Ga2O3 composite material. The method of the present application directly prepares the material using a high-temperature melting quenching method in an air atmosphere, and the material has high stability.

[0048] In a specific embodiment, the steps of the melt quenching method are as follows:

[0049] a. Taking PbO and Ga2O3, and placing them in an oven at 1000-1200℃ for heat preservation until the PbO and Ga2O3 are completely melted into a melt;

[0050] b. Pouring the melt onto a metal plate after mixing, and cooling in air to obtain the amorphous PbO / Ga2O3 composite material.

[0051] When the prepared amorphous PbO / Ga2O3 composite material has a molecular formula of (PbO) x (Ga2O3)1-x The ratio of the amount of raw material PbO to raw material Ga2O3 is x (mol) : 1-x (mol).

[0052] The melting method in step a is preferably holding at 1050°C for 15 min.

[0053] In step b, the metal plate is used for rapidly cooling the melt, and the material of the metal plate is selected to be able to not react with the melt. In the experiment of the present application, the metal plate is preferably a pure nickel plate.

[0054] In one embodiment, the prepared amorphous PbO / Ga2O3 composite material is placed in 300-350°C for 20-36 h, so as to eliminate the stress of the material; in one specific embodiment, the material is placed in 350°C for 24 h.

[0055] The present application also provides an X-ray detector.

[0056] The X-ray detector comprises, from bottom to top, a substrate, a bottom electrode, an amorphous (PbO) x (Ga2O3) 1-x bulk and a top electrode;

[0057] The substrate is used for bearing the amorphous (PbO) x (Ga2O3) 1-x bulk with the bottom and top electrodes, and functions to support, insulate and conduct heat; in one specific embodiment, the substrate is a glass substrate or a ceramic substrate.

[0058] The bottom electrode is deposited on the bottom surface of the amorphous (PbO) x (Ga2O3) 1-x bulk; the top electrode is deposited on the upper surface of the amorphous (PbO) x (Ga2O3) 1-x bulk; the amorphous (PbO) x (Ga2O3) 1-x bulk is obtained by cutting and polishing the amorphous PbO / Ga2O3 composite material.

[0059] In one embodiment, the electrode deposition method can adopt the conventional deposition method in the prior art, such as physical vapor deposition; the present application preferably adopts the method of plasma sputtering to prepare the electrode layer.

[0060] In one embodiment, the X-ray detector further comprises encapsulation glue, which is used for encapsulating the whole device and isolating water and oxygen.

[0061] In an embodiment, the X-ray detector further comprises silver paste and silver wire; wherein the silver wire is used as the electrode wire for testing, and the silver paste is used to connect the silver wire to the bottom surface and the surface electrode.

[0062] In an embodiment, the amorphous (PbO) x (Ga2O3) 1-x The thickness of the bulk is 600-1700 μm; when the thickness is 600 μm, the detector can absorb 80% of the X-rays; when the thickness is 1700 μm, the detector can absorb 99% of the X-rays; preferably, the amorphous (PbO) x (Ga2O3) 1-x The thickness of the bulk is 600-860 μm, within which range 80%-90% of the X-rays can be absorbed, which is completely sufficient for the absorption capacity of the X-ray detector; if 100% of the X-rays is to be absorbed, the thickness of the material needs to be 6340 μm, which is completely unnecessary, and the excessively large thickness makes it impossible to collect the generated photo-generated carriers.

[0063] In an embodiment, the thickness of the bottom electrode is 20-50 nm, and the thickness of the top electrode is 20-50 nm; preferably, the thickness of the bottom electrode and the top electrode is 30 nm, respectively.

[0064] In an embodiment, the amorphous (PbO) x (Ga2O3) 1-x The bulk is cut into a rectangular shape with an area of 0.66 cm 2 of the amorphous (PbO) x (Ga2O3) 1-x bulk; preferably, the cutting speed is set to 0.3-1 mm / min.

[0065] In an embodiment, the polishing method of the amorphous PbO / Ga2O3 composite material is: polishing with 1000-mesh, 2000-mesh, 7000-mesh sandpaper and diamond polishing gel in sequence. After polishing, the surface and the bottom surface are uniform and smooth.

[0066] In an embodiment, the electrode material of the top electrode and the bottom electrode is selected from one or a combination of two or more of Au, Ti, Ni, ITO, Al, Cr, conductive carbon paste, conductive silver paste, carbon nanotube, graphene and conductive copper foil; preferably, the electrode material of the bottom electrode and the top electrode is Au.

[0067] In an embodiment, the area of the bottom electrode ranges from the entire bottom surface of the amorphous (PbO) x (Ga2O3) 1-x bulk; the top electrode is a single electrode or an array electrode; when the top electrode is a single electrode, the area ranges from the amorphous (PbO)x (Ga2O3) 1-x The whole upper surface of the bulk; when the top electrode is an array electrode, the top electrode is prepared through an m x n mask, to form an m x n array electrode, where m≥2, n≥2. For example, the array can be 2 x 2, 3 x 3, 3 x 2, 10 x 10, etc. Preferably, m=3, n=3.

[0068] In a specific embodiment, the operation method for electrode deposition is as follows: the amorphous (PbO)x(Ga2O3)1-x bulk is placed in a vacuum chamber, and a bottom electrode layer is prepared by sputtering. The deposition material is Au. The Au target is fixed on the sputtering target position, the vacuum chamber is pumped to 4.0E-2 Pa, the sputtering power is turned on, the current is set to 4 mA, the sputtering time is 4 minutes, and the thickness of the Au electrode layer is measured by a step meter, which is 30 nm. When the array electrode is prepared, the top electrode is prepared through an array mask to form an array electrode. x (Ga2O3) 1-x The bulk is mounted on a sputtering platform, and a bottom electrode layer is prepared by plasma sputtering. The deposition material is Au. The Au target is fixed on the sputtering target position, the vacuum chamber is pumped to 4.0E-2 Pa, the sputtering power is turned on, the current is set to 4 mA, the sputtering time is 4 minutes, and the thickness of the Au electrode layer is measured by a step meter, which is 30 nm. When the array electrode is prepared, the top electrode is prepared through an array mask to form an array electrode.

[0069] The above content of the present application is further described in detail through the following specific embodiments in the form of examples. However, this should not be understood as the scope of the above subject matter of the present application being limited to the following examples. Any technology realized based on the above content of the present application falls within the scope of the present application, and the specific protection scope is shown in the claims.

[0070] Example 1

[0071] The amorphous (PbO)x(Ga2O3)1-x bulk and X-ray detector are prepared according to the following steps.

[0072] (1) Take x=0.698, and mix 20 g of raw materials of PbO and Ga2O3 in a ceramic crucible according to the molar ratio of PbO to Ga2O3 being 0.698:0.302.

[0073] (2) Put the ceramic crucible containing PbO and Ga2O3 into a box furnace, and keep it at 1050℃ for 15 minutes.

[0074] (3) Take out the ceramic crucible containing PbO and Ga2O3 from the box furnace, and manually stir the melt.

[0075] (4) Pour the melt after manual homogenization onto a nickel plate, and cool it in air to obtain an orange-yellow transparent amorphous (PbO)x(Ga2O3)1-x bulk. x (Ga2O3) 1-x Bulk.

[0076] (5) Put the amorphous (PbO)x(Ga2O3)1-x bulk into a box furnace, and keep it at 350℃ for 24 hours to eliminate stress. x (Ga2O3) 1-x Bulk.

[0077] (6) Cutting amorphous PbO with a cutting machine x (Ga2O3) 1-x The block was cut at a speed of 1 mm / min, resulting in an area of ​​0.66 cm². 2 Rectangular amorphous state (PbO) x (Ga2O3) 1-x Block.

[0078] (7) Transform the rectangle (PbO) x (Ga2O3) 1-x The block was polished using 1000-grit, 2000-grit, and 7000-grit sandpaper and diamond polishing adhesive, resulting in a uniform and smooth surface and bottom. The polished rectangular (PbO) shape... x (Ga2O3) 1-x The block is available in five thicknesses: 200μm, 400μm, 600μm, 800μm, and 1000μm.

[0079] (8) Using plasma sputtering to deposit rectangular amorphous (PbO) x (Ga2O3) 1-x A bottom electrode layer and a top electrode are deposited on the bulk material. The electrode material for both the bottom and top electrodes is Au, and the electrode layer thickness for both the bottom and top electrodes is 30 nanometers.

[0080] Wherein, a. the bottom electrode area is rectangular (PbO). x (Ga2O3) 1-x a. The entire bottom surface of the block; b. The top electrode is a single electrode with a rectangular area (PbO). x (Ga2O3) 1-x The entire upper surface of the block.

[0081] (9) Connect silver wires by applying silver paste to the bottom and surface electrodes; the silver wires serve as the electrode wires for testing.

[0082] (10) A rectangular (PbO) plate with bottom and top electrodes deposited on it. x (Ga2O3) 1-x The block is placed on a glass substrate and the entire device is encapsulated with Dow Corning 3140 encapsulating adhesive.

[0083] Example 2

[0084] In the scheme of Example 1, only the molar ratio of raw materials in step (1) is changed, that is, the x value is changed to 0.747, 0.761 or 0.789, and the rest of the process is the same as in Example 1.

[0085] Amorphous (PbO) was prepared. 0.747 (Ga2O3)0.253 Bulk, amorphous (PbO) 0.761 (Ga2O3) 0.239 Bulk, amorphous (PbO) 0.789 (Ga2O3) 0.211 The block, and its corresponding X-ray detector.

[0086] Example 3

[0087] In the scheme of Example 1, only steps 1, 6, 7 and 8 are changed, while the remaining steps remain unchanged.

[0088] The modified step 1 is as follows: Take 20g of raw material according to the molar ratio of PbO to Ga2O3 of 0.789:0.211 and mix it thoroughly in a ceramic crucible.

[0089] The modified step 6 is: cut the amorphous (PbO) using a cutting machine. x (Ga2O3) 1-x The bulk material was cut at a speed of 1 mm / min to obtain a rectangular amorphous (PbO) structure with an area of ​​10 mm × 10 mm. x (Ga2O3) 1-x Block.

[0090] The modified step 7 is: [The text abruptly ends here, likely due to an incomplete sentence or a formatting error.] x (Ga2O3) 1-x The block was polished using 1000-grit, 2000-grit, and 7000-grit sandpaper and diamond polishing adhesive, resulting in a uniform and smooth surface and bottom. The polished rectangular amorphous (PbO) material... x (Ga2O3) 1-x The block has a thickness of 600 μm.

[0091] The modified step 8 is: using plasma sputtering to deposit the material in a rectangular amorphous state (PbO). x (Ga2O3) 1-x A bottom electrode layer and a top electrode are deposited on a bulk substrate. The electrode material for both the bottom and top electrodes is Au, and the thickness of the electrode layers for both the bottom and top electrodes is 30 nanometers. The bottom electrode has a rectangular area (PbO). x (Ga2O3) 1-x The entire bottom surface of the block; the top electrode is an array electrode, which requires a 3×3 mask.

[0092] An X-ray detector was fabricated.

[0093] Example 4

[0094] Based on Example 1, only steps (1) and (2) are changed, while the remaining steps are the same as in Example 1. An X-ray detector is thus obtained.

[0095] Step (1) is changed to: taking x = 0.6, taking 20 g of raw materials according to the molar ratio of PbO to Ga2O3 as 0.6:0.4, and mixing them thoroughly in a ceramic crucible.

[0096] Step (2) is changed to: putting the ceramic crucible containing PbO and Ga2O3 into a box furnace, and keeping it at 1200°C until it melts.

[0097] Test Example 1

[0098] The (PbO) x (Ga2O3) 1-x bulk prepared in Examples 1 and 2 is subjected to X-ray diffraction test and scanning electron microscope observation.

[0099] The (PbO) x (Ga2O3) 1-x bulk prepared in Examples 1, 2, 3 and 4 is subjected to X-ray diffraction test, and as shown in Figure 4 , there is no diffraction peak or crystal orientation in the spectrum. The (PbO) x (Ga2O3) 1-x bulk is observed by scanning electron microscope, and as shown in Figure 5 , the surfaces of the (PbO) x (Ga2O3) 1-x bulk prepared in four ratios have no crystallization; Figure 6 The cross sections of the (PbO) x (Ga2O3) 1-x bulk can obviously find that the (PbO) x (Ga2O3) 1-x bulk prepared in four ratios has no interface and no crystallization. The results of X-ray diffraction test and scanning electron microscope observation together show that the method of high-temperature melting quenching can directly prepare amorphous (PbO) x (Ga2O3) 1-x bulk.

[0100] Test Example 2

[0101] The X-ray detectors prepared in Examples 1, 2 and 4, and the detectors prepared by using PbO, Ga2O3 and CdZnTe as photoelectric functional layers are tested, and the absorption rate of the device to X-ray photons with a tube voltage of 60 kV is tested. The results are shown in Table 1 and Figure 7 .

[0102] Table 1 and Figure 7The absorption rate of the X-ray photons of 60 kV tube voltage of the device prepared in the example is about 80% (when the thickness of the functional layer is 600 μm), while the X-ray absorption rates of the simple PbO and Ga2O3 at the same thickness are about 90.5% and 34.9% respectively, which shows that the amorphous (PbO)x(Ga2O3) 1-x bulk has high absorption efficiency to X-ray.

[0103] Table 1

[0104]

[0105] Test Example 3

[0106] The X-ray detectors prepared in the example 1 and the example 2 are applied with an electric field of 100 v / mm, and the lowest dark current thereof is tested by using a semiconductor analyzer. The results are shown in Table 2 and Figure 8

[0107] Table 2

[0108]

[0109] The amorphous (PbO)x(Ga2O3) bulk with x = 0.789 has the lowest dark current of 7.3E-13 A (0.73 pA), the area of the device is 0.66 square centimeter, and the converted dark current density is 1.1 pA / cm 2 , which is 100 orders of magnitude lower than the recommended index (10 pA / mm 2 ).

[0110] Test Example 4

[0111] The X-ray detectors prepared in the example 1 and the example 2 are tested. The amorphous (PbO) x (Ga2O3) 1-x bulk is irradiated with X-ray of 60 kV tube voltage and 0.3 mA tube current, and the photocurrent density thereof is tested under the same bias voltage. The results are shown in Table 3 and Figure 9

[0112] Table 3

[0113]

[0114] The amorphous (PbO) x (Ga2O3) 1-x bulk with x = 0.789 has the highest photocurrent density of 1.6E-9 A / cm 2 (1600 pA / cm 2 ), the current value under illumination reaches 1454 times of the dark current, and the net photocurrent density value after deducting the dark current is 1598.9 pA / cm 2 ​​This indicates that it is amorphous (PbO). x (Ga2O3) 1-x The bulk material exhibits a significant response to X-rays.

[0115] Experimental Example 5

[0116] The signal-to-noise ratio of the X-ray detectors prepared in Examples 1 and 2 was tested under X-ray irradiation at an electric field of 100 V / mm and different dose rates. The results are shown in Table 4. Figure 10 As shown.

[0117] Table 4

[0118]

[0119] At an X-ray dose rate of 0.57 μGy (60 kV 300 μA), the detector with x = 0.761 has a signal-to-noise ratio as high as 800, which indicates that the device has strong noise immunity.

[0120] Experimental Example 6

[0121] The sensitivity of the X-ray detectors prepared in Examples 1 and 2 was tested under different electric field intensities. The results are shown in Table 5. Figure 11 As shown.

[0122] Table 5

[0123]

[0124] The prepared amorphous (PbO)x(Ga2O3)1-x bulk X-ray detector with x=0.789 has a sensitivity of 2.82 uC / Gy / cm2, which is close to that of commercial amorphous selenium X-ray detectors.

[0125] Experimental Example 7

[0126] Test the (PbO) prepared in Example 3 x (Ga2O3) 1-x Dark and photocurrents of bulk X-ray detector arrays, such as Figure 12 As shown, the dark current ranges from 21 to 28 pA, and the photocurrent ranges from 807 to 942 pA. This indicates that the detector array has low dark current, high photocurrent, and good uniformity. The testing methods for photocurrent and dark current are consistent with those in Experiments 3 and 4.

[0127] The four electrodes of the detector were covered with a 2mm copper plate, and the uniformity was characterized using a semiconductor analyzer. The resulting image is shown below. Figure 13 As shown, the current distribution is uniform. This indicates that the developed detector has good uniformity.

Claims

1. An X-ray detector, characterized in that, It includes, from bottom to top, a substrate, a bottom electrode, and amorphous (PbO). x (Ga2O3) 1-x Bulk and top electrode; The bottom electrode is deposited in an amorphous state (PbO). x (Ga2O3) 1-x The bottom surface of the bulk material; the top electrode is deposited on amorphous (PbO). x (Ga2O3) 1-x The upper surface of the bulk material; the amorphous state (PbO). x (Ga2O3) 1-x The bulk material is obtained by cutting and polishing amorphous PbO / Ga2O3 composite material, with 0.6 ≤ x < 0.8; The thickness of the amorphous (PbO)x(Ga2O3)1-x bulk is 600~1700μm, and the thickness of the bottom electrode and the top electrode is 20~50nm.

2. The X-ray detector according to claim 1, characterized in that, The amorphous state (PbO) x (Ga2O3) 1-x The thickness of the bulk material is 600~860μm, and the thickness of both the bottom and top electrodes is 30nm.

3. The X-ray detector according to claim 1, characterized in that, The polishing method for amorphous PbO / Ga2O3 composite materials is as follows: polishing is performed sequentially with 1000-grit, 2000-grit, and 7000-grit sandpaper and diamond polishing adhesive.

4. The X-ray detector according to claim 1, characterized in that: The electrode materials for the top and bottom electrodes are selected from one or more of Au, Ti, Ni, ITO, Al, Cr, conductive carbon paste, conductive silver paste, carbon nanotubes, graphene, and conductive copper foil; the substrate is a glass substrate or a ceramic substrate.

5. The X-ray detector according to claim 4, characterized in that: The electrode material for both the bottom and top electrodes is Au.

6. The X-ray detector according to claim 1, characterized in that, The bottom electrode area is in the amorphous state (PbO). x (Ga2O3) 1-x The entire bottom surface of the block; the top electrode is a single electrode or an array of electrodes; when the top electrode is a single electrode, the area range is amorphous (PbO). x (Ga2O3) 1-x The entire upper surface of the block; when the top electrode is an array electrode, the top electrode is used to prepare an m×n array electrode through an m×n mask, where m≥2 and n≥2.

7. The X-ray detector according to claim 6, characterized in that, m=3, n=3.

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