Defect recognition device based on perovskite semiconductor single crystal detector imaging

Abstract

The invention relates to the technical field of semiconductor detector defect recognition, and discloses a defect recognition device based on perovskite semiconductor single crystal detector imaging, which is characterized in that a visual camera is focused on a perovskite semiconductor single crystal detector through a spatial light path device and an objective lens focusing system, and a starting point and an ending point of an area to be scanned are determined. The pulse laser focuses laser spots on the detector through the attenuation piece and the spatial light path device, and the two-dimensional mobile platform moves at a preset step length under the driving of the control module to realize micro-area scanning; meanwhile, the test module applies voltage through a voltage input end, so that the detector generates a vertical electric field, a response signal is converted into a test signal in the scanning process, and the defect distribution position is obtained. Based on the signal response when each point is excited by the single pulse laser spot, the relation between the local defect and the photoelectric response signal in the perovskite semiconductor single crystal detector can be accurately represented, the local response difference is disclosed, and local defect identification is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor detector defect recognition, and in particular to a defect recognition device based on imaging of a perovskite semiconductor single crystal detector. Background Art

[0002] Nuclear radiation detection technology plays a vital role in radiation measurement and positioning, and is widely used in many fields such as energy development, medical health, industrial testing, environmental monitoring and scientific research.

[0003] In the field of high-energy radiation detection, detectors require large thickness and area to ensure high detection efficiency and sensitivity. However, semiconductor materials inevitably introduce various defects during crystal growth, significantly affecting the detector's carrier transport performance and photoelectric response uniformity, especially in large-scale semiconductor crystals. New perovskite semiconductors exhibit numerous microstructural defects, limiting the uniformity of device response in large single crystals. During melt growth, perovskite crystals undergo thermostructural phase transitions, inducing thermal stress, which in turn creates residual stress and leads to defects such as cracks, subgrain boundaries, and twins. Furthermore, during detector fabrication, imperfect contact between metal electrodes and semiconductor materials (such as surface scratches) can also affect carrier collection. Overall, microscopic defects in crystal growth processing and device fabrication can cause electric field distortion and charge trapping, leading to carrier drift path deviations and photogenerated electron-hole pair recombination losses. This results in variations in photoelectric response intensity across different regions of the detector, affecting spatial response uniformity and degrading energy resolution.

[0004] The spatial uniformity of the photoelectric response is one of the key parameters for measuring the quality and stability of the detector, and directly affects the energy resolution, spatial resolution of the imaging system, image quality, and ultimately the accuracy of quantitative analysis. In order to obtain high detection performance and excellent imaging resolution, it is necessary to screen out high-performance and uniformly responsive semiconductor crystals. Currently, conventional overall response test methods (such as total count rate testing under surface source irradiation) can only reflect the average performance of the device, and cannot reveal local response differences and their corresponding defect locations and types. The current lack of systematic equipment and methods makes it difficult to directly characterize and study the relationship between defects and carrier transport and collection performance in high-throughput or single-photon irradiation scenarios, and it is difficult to provide an accurate basis for the correlation study between defects and carrier transport performance, device quality grading, troubleshooting, and optimization of crystal growth and device preparation processes.

[0005] The detection performance of nuclear radiation detection semiconductors is closely related to their intrinsic carrier transport properties, and the distribution of defects in semiconductors has a significant impact on the transport of photogenerated carriers. Existing equipment for characterizing semiconductor defects and carrier transport properties typically focuses on a single aspect of research. For example, morphological observations using scanning electron microscopy (SEM) and transmission electron microscopy (TEM) can reveal structural information about crystal defects; optical steady-state and transient fluorescence spectroscopy analysis can help study carrier recombination behavior and migration characteristics; and electrical photocurrent response testing can reveal defect concentrations and electrical properties during carrier migration.

[0006] However, most existing testing systems primarily focus on analyzing the overall performance of semiconductor materials, particularly in large-scale semiconductor crystals. They struggle to accurately characterize local defects and fail to effectively correlate defect distribution with carrier transport performance in different application scenarios (high-flux irradiation and single-photon detection). This makes it difficult for existing characterization methods to provide precise guidance for optimizing growth techniques and device fabrication processes for nuclear radiation detection semiconductor crystals, hindering the full potential of materials and devices.

[0007] Perovskite is a new generation of semiconductor materials for nuclear radiation detection, and its research is still in the preliminary exploratory stage. The carrier transport behavior in the material is affected by multiple factors such as intrinsic electrically active defects, twin structures, dislocations, and non-intrinsic impurity atoms, but the specific mechanism of action has not yet been clarified. At present, there is still a lack of systematic and in-depth research on the coupling relationship between internal defects in the crystal and detection performance, especially in terms of the impact of different types of defects on key performance parameters such as device sensitivity, energy resolution and response time in various nuclear radiation detection application scenarios. In addition, during the processing of crystals and devices, processes such as surface roughness, charge injection at the interface, recombination behavior and energy level alignment also have an important impact on detection performance. At present, the influence of interface structure on carrier collection is indirect inference, lacking intuitive characterization methods with high temporal and spatial resolution, and the understanding of its photoelectric response mechanism is still insufficient.

[0008] Existing technologies focus solely on characterizing structural defects or the overall electrical and performance characteristics of detectors. While these techniques can provide basic performance evaluations to a certain extent, they still have significant shortcomings in correlating high-resolution, micro-area defect analysis with carrier transport properties. Electron microscopes (SEM, TEM) and atomic force microscopes (AFM) provide nanoscale structural imaging capabilities and can be used to analyze the morphology of typical structural defects in crystals, such as dislocations, grain boundaries, twins, and surface roughness. These methods are suitable for studying material morphology and defect types, but they are primarily used for static structural analysis and cannot yet directly correlate with the detector's photoelectric response performance. Common electrical measurement methods include Hall effect measurements, carrier mobility and lifetime testing, and I–V and C–V characterization, which can be used to evaluate the material's overall carrier transport capacity. These tests can reflect the material's intrinsic electrical properties, but they are generally unable to directly resolve the local electric field distortion or carrier recombination mechanisms caused by defects, and it is also difficult to establish a corresponding relationship with spatially uneven photoelectric response characteristics. For currently commercially available semiconductor detectors, overall response testing methods are conventionally used, such as the total count rate test under surface source illumination, which can evaluate the average performance of the detector under different radiation sources. These methods usually reflect the overall performance of the device by measuring the total count rate or energy resolution of the detector. However, this method cannot reveal local response differences or identify performance fluctuations caused by defects.

[0009] In summary, existing testing methods cannot reveal local differences and cannot accurately identify photoelectric response non-uniformity caused by detector defects; for high-throughput scanning, defects may lead to nonlinear saturation of photocurrent or non-uniform response; for single-photon modes, defects may cause energy spectrum broadening (energy resolution reduction) or pulse signal loss; therefore, existing devices cannot achieve pulse signal imaging under single-pulse excitation, and thus cannot associate the laser-based response signal of the perovskite semiconductor single crystal detector with the detector defects, cannot perform local defect identification, and cannot accurately evaluate the photoelectric response uniformity of the perovskite semiconductor single crystal detector. Summary of the Invention

[0010] To this end, the technical problem to be solved by the present invention is to overcome the problem that the existing technology is unable to perform single-pulse excitation imaging on perovskite semiconductor single crystal detectors, and thus is unable to realize the local defect identification of perovskite semiconductor single crystal detectors, and is unable to accurately evaluate the uniformity of the photoelectric response of perovskite semiconductor single crystal detectors.

[0011] To solve the above technical problems, the present invention provides a defect recognition device based on imaging of a perovskite semiconductor single crystal detector, comprising: A light-shielding device is provided with: Objective lens focusing system; The electromagnetic shielding box has a quartz window on the top, a grounding port, a current output port, and a voltage input port on the side, and contains: 2D mobile platform; A stage is provided on the upper surface of the two-dimensional movable platform, for placing a perovskite semiconductor single crystal detector; the top electrode of the perovskite semiconductor single crystal detector is connected to the ground port or the current input terminal, and the bottom electrode is connected to the voltage input terminal; The visualization camera focuses on the perovskite semiconductor single crystal detector through the first incident surface of the spatial optical path device, the objective lens focusing system and the quartz window, and obtains the starting point and end point of the area to be scanned of the perovskite semiconductor single crystal detector; After obtaining the starting point and end point of the area to be scanned, the pulsed laser focuses the laser spot on the perovskite semiconductor single crystal detector through the attenuation plate, the second incident surface of the spatial optical path device, the objective lens focusing system, and the quartz window, so that the laser spot scans from the starting point to the end point of the area to be scanned while the control module controls the two-dimensional moving platform to move at a preset step size; A test module, one end of which is connected to the bottom electrode of the perovskite semiconductor single crystal detector through a voltage input terminal. When the laser spot reaches the starting point of the area to be scanned, a voltage is applied to the perovskite semiconductor single crystal detector, causing the perovskite semiconductor single crystal detector to generate a vertical electric field and generate a response signal during the micro-area scanning process. The response signal is converted into a test signal, and a distribution image of the test signal is obtained, so as to obtain the defect distribution position of the perovskite semiconductor single crystal detector based on the distribution image of the test signal; Among them, the output surface of the visualization camera and the first incident surface of the spatial optical path device are coaxial; the pulse laser, the attenuation plate, and the second incident surface of the spatial optical path device are coaxial; the output surface of the spatial optical path device, the objective lens focusing system and the quartz window are coaxial.

[0012] Preferably, the control module controls the two-dimensional mobile platform to move with a preset step length, including: Get the starting coordinates of the area to be scanned of the perovskite semiconductor single crystal detector captured by the visualization camera and the end point coordinates , and preset the step size 、 ; Control the two-dimensional mobile platform to carry the perovskite semiconductor single crystal detector on the stage to move so that the laser spot is located at the starting point of the area to be scanned, and move along the x-axis in the row where the starting point is located according to the step size. Move and perform micro-area scanning at each point to be scanned until the laser spot reaches , the line is scanned; Control the two-dimensional mobile platform to carry the perovskite semiconductor single crystal detector on the stage to move so that the laser spot returns along the x-axis direction Then, step along the y-axis , perform micro-area scanning on the points to be scanned in the current row in sequence until stepping along the y-axis direction The y-axis coordinate after is greater than , completing the process of the laser spot scanning from the starting point to the end point of the area to be scanned.

[0013] Preferably, when the pulse laser outputs low-flux pulse laser, the test module is a pulse signal test module, comprising: A high-voltage module, one end of which is connected to the bottom electrode of the perovskite semiconductor single crystal detector through the voltage input terminal, and a positive voltage is applied to excite the perovskite semiconductor single crystal detector to generate electron-hole pairs, and the holes are collected by the top cathode, and the electrons drift to the bottom anode, thereby generating an induction signal between the top electrode and the bottom electrode of the perovskite semiconductor single crystal detector; The pulse signal analysis and processing module has one end connected to the bottom electrode of the perovskite semiconductor single crystal detector through the voltage input end, obtains the sensing signal and converts it into oscilloscope data as the test signal output of the test module.

[0014] Preferably, obtaining the defect distribution position of the perovskite semiconductor single crystal detector based on the distribution image of the test signal includes: Based on the test signal, the main amplifier pulse signal is collected in real time to construct a pulse amplitude distribution diagram; Based on the pulse amplitude distribution diagram, the position corresponding to the laser spot of the low-flux pulsed laser on the perovskite semiconductor single crystal detector when the pulse amplitude is not greater than the preset amplitude threshold is used as the defect distribution position of the perovskite semiconductor single crystal detector.

[0015] Preferably, the pulse signal analysis and processing module includes: The first amplifying unit has an input end connected to the bottom electrode of the perovskite semiconductor single crystal detector through the voltage input end on the electromagnetic shielding box to obtain the sensing signal and generate a preamplifier pulse signal output; The second amplifying unit, whose input end is connected to the output end of the first amplifying unit, obtains the pre-amplifier pulse signal and generates the main amplifying pulse signal output; a pulse waveform analysis submodule, the input end of which is connected to the output end of the first amplifying unit and the output end of the second amplifying unit, and uses an oscilloscope to display amplitude information in real time as oscillographic data based on the preamplifier pulse signal and the main amplifier pulse signal; Alternatively, the multi-channel pulse signal analysis submodule, whose input end is connected to the output end of the second amplifying unit, classifies the pulse amplitudes of the main amplified pulse signal by channel address and generates amplitude histogram distribution information as oscillographic data.

[0016] Preferably, when the pulse laser outputs high-flux pulse laser, the test module is a photocurrent integral signal test module, comprising: An electrical test module, one end of which is connected to the bottom electrode of the perovskite semiconductor single crystal detector through the voltage input end; by applying a positive voltage to the bottom electrode of the perovskite semiconductor single crystal detector, the perovskite semiconductor single crystal detector is excited to generate electron-hole pairs, and the holes are collected by the top cathode, and the electrons drift to the bottom anode, thereby generating an induction signal between the electrodes and generating a vertical electric field; one end of which is connected to the top electrode of the perovskite semiconductor single crystal detector through the current output end, and the photocurrent signal of the top electrode is collected by using the current output end.

[0017] Preferably, obtaining the defect distribution position of the perovskite semiconductor single crystal detector based on the distribution image of the test signal includes: Record photocurrent signals in real time and generate photocurrent distribution images; Based on the photocurrent distribution image, the position corresponding to the laser spot of the high-flux pulsed laser on the perovskite semiconductor single crystal detector when the current value in the photocurrent distribution image is not greater than the preset current threshold is used as the defect distribution position of the perovskite semiconductor single crystal detector.

[0018] Preferably, it also includes: The beam splitting slot is provided between the spatial optical path device and the objective lens focusing system, and is coaxial with the exit surface of the spatial optical path device, the objective lens focusing system and the quartz window; The light intensity recording module based on silicon photodiode is integrated into the beam splitting slot and communicates with the data acquisition module. It is used to record the reflected light intensity of the perovskite semiconductor single crystal detector in real time, and to perform real-time imaging in the data acquisition module to obtain a light intensity distribution image.

[0019] Preferably, the perovskite includes three-dimensional perovskite, two-dimensional perovskite, zero-dimensional perovskite and antiperovskite; The three-dimensional perovskite is selected from A1B1X13; wherein A1 is selected from one or more of Na, K, Rb, Cs, Cu, Tl and H3O, B1 is selected from one or more of Pb, Si, Ge, Sn, Mg, Ca, Sr, Ba, Zn, Cd and Hg, and X1 is selected from one or more of F, Cl, Br, I, BF4, HCOO, OH, CN, SCN, NCS, SH, NO3 and H2POO; The two-dimensional perovskite is selected from TlPbI3 or A23B22X29; wherein A2 is selected from one or both of Cs and Rb, B2 is selected from one or both of Sb and Bi, and X2 is selected from one or more of F, Cl, Br and I; The zero-dimensional perovskite is selected from Cs3Bi2I9, Cs2TeI6, Cs2TeBr6 or Cs2TeCl6; The antiperovskite is selected from Hg3Se2Br2 or TlSn2I5.

[0020] Preferably, it further comprises: a temperature control platform, which is arranged between the upper surface of the stage and the lower surface of the perovskite semiconductor single crystal detector, so as to control the test temperature in the electromagnetic shielding box.

[0021] The above technical solution of the present invention has the following beneficial effects compared with the prior art:

[0022] The defect identification device based on imaging of a perovskite semiconductor single crystal detector described in the present invention is based on a frequency-adjustable pulsed laser and a two-dimensional displacement platform. It uses a single-pulse laser with a very small laser spot as an excitation source, which can be focused on a point on the semiconductor crystal detector to observe the photoelectric response of the point. At the same time, with the help of the displacement platform, the position of the semiconductor crystal detector is moved so that the laser spot can scan the entire area, thereby obtaining the photoelectric response signal of this area, and recording the signal response at different positions in real time to form a response distribution imaging. This application realizes micro-area scanning of the detector based on the signal response of each point in the detector to be scanned when excited by the laser spot. It can accurately characterize the relationship between local defects and photoelectric response uniformity in the perovskite semiconductor single crystal detector, reveal local response differences, and thus determine whether the detector has defects based on whether the response is uniform, thereby realizing local defect identification, which is conducive to selecting defect-free perovskite semiconductor single crystal detectors for nuclear radiation detection applications, achieving uniform response, and thus improving radiation imaging accuracy.

[0023] The defect identification device of the present invention is based on the imaging of perovskite semiconductor single crystal detectors. When performing detector photoelectric response signal imaging, it includes high-flux photocurrent integral scanning imaging and low-flux pulse signal scanning imaging. It can simulate high-flux and single-photon irradiation scenarios in nuclear radiation detection scenarios. Based on single-pulse excitation spatial response uniformity imaging, it can further perform a visual evaluation of response uniformity and carrier transport performance, providing a basis for the correlation between defects and carrier transport performance, and the screening of high-performance detectors.

[0024] At the same time, by changing the voltage applied to the detector and obtaining the response signals under different voltages, the carrier mobility-lifetime product, the spatial distribution map of mobility and lifetime can be further calculated. Based on these imaging data, the correlation between material defect distribution and carrier transport performance can be deeply analyzed and revealed, providing a reliable basis for the quality assessment, crystal growth processing and device preparation process optimization of perovskite semiconductor single crystal detectors. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to make the content of the present invention more clearly understood, the present invention is further described in detail below based on specific embodiments of the present invention in conjunction with the accompanying drawings, wherein: Figure 1 This is a structural diagram of a defect recognition device based on imaging of a perovskite semiconductor single crystal detector according to the present invention; Figure 2 It is a structural diagram of a defect recognition device in low-throughput pulse signal scanning mode; Figure 3 It is the structural diagram of the pulse signal analysis and processing module; Figure 4 is a structural diagram of the first amplification unit; Figure 5 This is a structural diagram of a defect recognition device in high-throughput photocurrent integration signal scanning mode; Figure 6 This is a schematic diagram of the pulse signal output during the low-flux pulse signal scanning imaging test; Figure 7 It is an imaging diagram of the amplitude of the preamplifier pulse signal or the amplitude of the main amplifier pulse signal; Figure 8 It is the imaging diagram of the rise time of the preamplifier pulse signal; Figure 9 is the pulse amplitude distribution histogram; Figure 10 It is the mobility distribution image of electrons at different positions; Figure 11 It is the lifetime distribution image of electrons at different positions; Figure 12 It is the mobility lifetime distribution image of electrons at different positions; Figure 13 This is the imaging result output in high-flux photocurrent integration scanning mode; Figure 14 This is the IV curve of a detector made of cesium lead bromine crystal; Figure 15 This is the It curve of a detector made of cesium lead bromine crystal; Figure 16 This is an image of the photocurrent distribution of a detector made of cesium lead bromine crystal; Figure 17 It is an image of the light intensity distribution reflected from the surface of the detector made of cesium lead bromine crystal; Figure 18 This is the pulse signal amplitude distribution image of the low-flux pulse signal scanning imaging test perovskite cesium lead bromine detector; Figure 19 This is the pulse signal amplitude distribution histogram of the low-flux pulse signal scanning imaging test perovskite cesium lead bromine detector; Figure 20This is the pulse signal distribution image of the detector made of perovskite crystal after only mechanical polishing; Figure 21 This is the pulse signal distribution image of the detector made of perovskite crystal after mechanical polishing and chemical etching; Explanation of the reference numerals in the specification: 1. Visualization camera; 2. Spatial optical path device; 3. Objective lens focusing system; 4. Quartz window; 5. Perovskite semiconductor single crystal detector; 6. Electromagnetic shielding box; 7. Laser controller; 8. Pulsed laser; 9. Attenuation plate; 10. Temperature control platform; 11. Stage; 12. Two-dimensional moving platform; 13. Grounding port; 14. Current output terminal; 15. Voltage input terminal; 16. Light shielding device; 17. High-voltage module; 18. Pulse signal analysis and processing module; 181. First amplification unit; 182. Second amplification unit; 183. Pulse waveform analysis submodule; 184. Multi-channel pulse signal analysis submodule; 19. Data acquisition module; 20. Control module; 21. Electrical test module; 22. Light intensity recording module; 23. Test module. DETAILED DESCRIPTION

[0026] The present invention will be further described below with reference to the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it. However, the embodiments are not intended to limit the present invention.

[0027] Direct detection of high-energy radiation in semiconductor materials is based on the photoelectric effect. There are two main detection modes: the photocurrent integration mode, used for high-flux radiation detection, and the pulse mode, which counts and collects energy from incident single high-energy photons / particles at low flux. In the photocurrent integration mode, high-flux, high-energy radiation interacts with the semiconductor, generating a large number of electron-hole pairs. These pairs drift toward the polarization under an applied bias, generating a photocurrent whose magnitude is proportional to the radiation dose rate. In the single-photon pulse mode, a limited number of electron-hole pairs generated by the interaction of a single incident photon / particle with the semiconductor drift toward the polarization under an applied bias, forming a pulse height spectrum, i.e., the energy spectrum of the radiation. In either mode, carrier transport properties are key factors in determining semiconductor detection performance. Under the same operating conditions, higher carrier mobility μ and longer lifetime τ increase the detector's collection efficiency for photogenerated carriers, thereby improving the detector's response sensitivity and energy spectrum resolution.

[0028] The perovskite includes three-dimensional perovskite, two-dimensional perovskite, zero-dimensional perovskite and antiperovskite; the three-dimensional perovskite is selected from A1B1X13; wherein A1 is selected from one or more of Na, K, Rb, Cs, Cu, Tl and H3O, B1 is selected from one or more of Pb, Si, Ge, Sn, Mg, Ca, Sr, Ba, Zn, Cd and Hg, and X1 is selected from F, Cl, Br, I, BF4, HCOO, OH, CN, SCN, NCS, SH, NO 3 and one or more of H2POO; the two-dimensional perovskite is selected from TlPbI3 or A23B22X29; wherein A2 is selected from one or both of Cs and Rb, B2 is selected from one or both of Sb and Bi, and X2 is selected from one or more of F, Cl, Br and I; the zero-dimensional perovskite is selected from Cs3Bi2I9, Cs2TeI6, Cs2TeBr6 or Cs2TeCl6; the antiperovskite is selected from Hg3Se2Br2 or TlSn2I5.

[0029] Reference Figure 1 As shown in FIG, the structure diagram of the defect recognition device based on imaging of a perovskite semiconductor single crystal detector of the present invention includes: The light-shielding device 16 is provided with: Objective lens focusing system 3; The electromagnetic shielding box 6 has a quartz window 4 on its top, a grounding port 13, a current output terminal 14 and a voltage input terminal 15 on its side, and is provided with: Two-dimensional mobile platform 12; The stage 11 is provided on the upper surface of the two-dimensional mobile platform, and is used to place the perovskite semiconductor single crystal detector 5; the top electrode of the perovskite semiconductor single crystal detector is connected to the ground port or the current input terminal, and the bottom electrode is connected to the voltage input terminal; The visualization camera 1 focuses on the perovskite semiconductor single crystal detector through the first incident surface of the spatial optical path device 2, the objective lens focusing system 3 and the quartz window 4, and obtains the starting point and end point of the area to be scanned of the perovskite semiconductor single crystal detector; After obtaining the starting point and end point of the area to be scanned, the pulsed laser 8 focuses the laser spot on the perovskite semiconductor single crystal detector through the attenuation plate 9, the second incident surface of the spatial optical path device 2, the objective lens focusing system 3, and the quartz window 4. This allows the laser spot to scan from the starting point to the end point of the area to be scanned while the control module 20 controls the two-dimensional moving platform to move at a preset step size. A test module 22, one end of which is connected to the bottom electrode of the perovskite semiconductor single crystal detector through a voltage input terminal. When the laser spot reaches the starting point of the area to be scanned, a voltage is applied to the perovskite semiconductor single crystal detector, causing the perovskite semiconductor single crystal detector to generate a vertical electric field and generate a response signal during the micro-area scanning process. The response signal is converted into a test signal, and a distribution image of the test signal is obtained, so as to obtain the defect distribution position of the perovskite semiconductor single crystal detector based on the distribution image of the test signal; Among them, the output surface of the visualization camera and the first incident surface of the spatial optical path device are coaxial; the pulse laser, the attenuation plate, and the second incident surface of the spatial optical path device are coaxial; the output surface of the spatial optical path device, the objective lens focusing system and the quartz window are coaxial.

[0030] Specifically, the embodiment of the present invention is equipped with single-pulse lasers of various wavelengths, ranging from 300nm to 1200nm, etc., for exciting perovskite semiconductor materials with different bandgap widths; the laser pulse width is 0.001ns to 1000ns, and the system adopts a spatial optical path design and is equipped with a multi-channel laser coupling optical path to ensure that each laser beam is incident on the objective lens, and the working modes of different lasers are switched by a pull rod. In addition, the pulse laser in the present invention has an adjustable repetition rate, and its internal trigger output frequency range is 2MHz~100MHz. The frequency of the output pulse laser can be adjusted to simulate the pulse signal scanning test in the single-photon mode, as well as the photocurrent integral scanning test under high-flux irradiation. At the same time, the laser can also be switched to an external trigger mode with a frequency range of 1Hz~50Hz to meet different test requirements.

[0031] Specifically, the objective focusing system of the present invention can be equipped with objective lenses of various magnifications, such as achromatic lenses with equivalent magnifications of 2x, 4x, and 8x, as well as 20x and 50x long working distance objective lenses. Furthermore, the system is equipped with a visualization camera, which, combined with the objective focusing system, enables micro-area observation and imaging of the detector surface topography.

[0032] Specifically, the electromagnetic shielding box of the present invention has an optical window on the top; the optical window is made of conductive transparent material, and the light-transmitting area is square and has a size of 1×1 mm. 2 Up to 50×50mm 2 ; Multiple input and output interfaces are installed on the side of the shielding box, including a grounding port, a current output port, and a voltage input port (sensing signal output port).

[0033] Specifically, the control module controls the two-dimensional mobile platform to move with a preset step length, including: Get the starting coordinates of the area to be scanned of the perovskite semiconductor single crystal detector captured by the visualization camera and the end point coordinates , and preset the step size 、 ; Control the two-dimensional mobile platform to carry the perovskite semiconductor single crystal detector on the stage to move so that the laser spot is located at the starting point of the area to be scanned, and move along the x-axis in the row where the starting point is located according to the step size. Move and perform micro-area scanning at each point to be scanned until the laser spot reaches , the line is scanned; Control the two-dimensional mobile platform to carry the perovskite semiconductor single crystal detector on the stage to move so that the laser spot returns along the x-axis direction Then, step along the y-axis , perform micro-area scanning on the points to be scanned in the current row in sequence until stepping along the y-axis direction The y-axis coordinate after is greater than , completing the process of the laser spot scanning from the starting point to the end point of the area to be scanned.

[0034] The two-dimensional mobile platform used in the embodiment of the present invention is a high-precision electric translation stage with a travel range of 10mm to 50mm and a moving step range of 1μm to 10000μm. Its movement process is controlled by the control module and its position information is obtained through the data acquisition module.

[0035] Reference Figure 2 FIG. 1 is a structural diagram of a defect recognition device in a low-flux pulse signal scanning mode; when the pulse laser outputs a low-flux pulse laser, the test module is a pulse signal test module, including: The high-voltage module 17 has one end connected to the bottom electrode of the perovskite semiconductor single crystal detector through the voltage input terminal, and applies a positive voltage to excite the perovskite semiconductor single crystal detector to generate electron-hole pairs, and the holes are collected by the top cathode, and the electrons drift to the bottom anode, thereby generating an induction signal between the top electrode and the bottom electrode of the perovskite semiconductor single crystal detector; The pulse signal analysis and processing module 18 has one end connected to the bottom electrode of the perovskite semiconductor single crystal detector through the voltage input end, and obtains the sensing signal and converts it into oscillographic data as the test signal output of the test module.

[0036] Reference Figure 3 FIG. 1 is a structural diagram of a pulse signal analysis and processing module; specifically, the pulse signal analysis and processing module includes: The first amplifying unit 181 has an input end connected to the bottom electrode of the perovskite semiconductor single crystal detector through the voltage input end on the electromagnetic shielding box, obtains the sensing signal, and generates a preamplifier pulse signal output; The second amplifying unit 182 has an input end connected to the output end of the first amplifying unit, obtains the preamplifier pulse signal, and generates a main amplifying pulse signal output; A pulse waveform analysis submodule 183, whose input end is connected to the output end of the first amplifying unit and the output end of the second amplifying unit, uses an oscilloscope to display amplitude information in real time as oscillographic data based on the preamplifier pulse signal and the main amplifier pulse signal; Alternatively, the multi-channel pulse signal analysis submodule 184 , whose input terminal is connected to the output terminal of the second amplifying unit, classifies the pulse amplitudes of the main amplified pulse signal by channel address and generates amplitude histogram distribution information as oscillographic data.

[0037] Reference Figure 4 FIG. 1 is a structural diagram of the first amplifying unit; the first amplifying unit is a charge-sensitive preamplifier circuit, comprising: an operational amplifier, wherein the positive input terminal thereof is grounded and the output terminal thereof serves as the output terminal of the first amplifying unit; a DC blocking capacitor, one end of which is connected to the inverting input terminal of the operational amplifier, and the other end of which serves as the input terminal of the first amplifying unit; a feedback resistor, one end of which is connected to the inverting input terminal of the operational amplifier, and the other end of which is connected to the output terminal of the operational amplifier; A feedback capacitor has one end connected to the inverting input terminal of the operational amplifier, and the other end connected to the output terminal of the operational amplifier.

[0038] Specifically, the first amplification unit 181 is a charge-sensitive preamplifier circuit used to amplify the weak sensing signal generated by the perovskite semiconductor single crystal detector 5 and transmit it to the pulse waveform analysis submodule 183 and the input of the second amplification unit 182. The first amplification unit 181 includes an operational amplifier U1, a DC blocking capacitor C1, a feedback resistor R1, and a feedback capacitor C2. The operational amplifier U1 has a built-in field-effect transistor (FET) input. The DC blocking capacitor C1 is a ceramic capacitor with a capacitance of 1nF to 1000nF, the feedback resistor R1 has a resistance of 50MΩ to 10GΩ, and the feedback capacitor C2 has a capacitance of 0.01pF to 500pF, which can match the sensing signals of different semiconductor detectors.

[0039] Specifically, the pulse waveform analysis submodule 183 receives the signal output by the first amplification unit 181 and displays the waveform data in real time on an oscilloscope. To improve signal quality and ensure more accurate and reliable data for subsequent analysis, the signal output by the first amplification unit 181 is filtered, shaped, and amplified by the second amplification unit 182, with a gain range of 1-1500 times. The output signal then enters the pulse waveform analysis submodule 183, where its amplitude information is displayed on an oscilloscope. It also enters the multi-channel pulse signal analysis submodule 184, where pulse amplitudes are classified by channel address and used to generate an amplitude distribution histogram in the data acquisition module.

[0040] When this embodiment uses a low-flux pulse signal to scan the perovskite semiconductor single crystal detector, the main pulse signal is collected in real time based on the test signal to construct a pulse amplitude distribution diagram; based on the pulse amplitude distribution diagram, the position corresponding to the laser spot of the low-flux pulse laser on the perovskite semiconductor single crystal detector when the pulse amplitude is not greater than the preset amplitude threshold is used as the defect distribution position of the perovskite semiconductor single crystal detector.

[0041] Reference Figure 5 As shown, it is a structural diagram of the defect recognition device in the high-flux photocurrent integral signal scanning mode; when the pulse laser outputs high-flux pulse laser, the test module is a photocurrent integral signal test module, including: an electrical test module 21, one end of which is connected to the bottom electrode of the perovskite semiconductor single crystal detector through the voltage input end; by applying a positive voltage to the bottom electrode of the perovskite semiconductor single crystal detector, the perovskite semiconductor single crystal detector is excited to generate electron-hole pairs, and the holes are collected by the top cathode, and the electrons drift to the bottom anode, thereby generating an induction signal between the electrodes and generating a vertical electric field; one end of which is connected to the top electrode of the perovskite semiconductor single crystal detector through the current output end, and the photocurrent signal of the top electrode is collected by the current output end.

[0042] This embodiment uses high-flux photocurrent integration to scan the perovskite semiconductor single crystal detector, recording the photocurrent signal in real time to generate a photocurrent distribution image; based on the photocurrent distribution image, when the current value in the photocurrent distribution image is not greater than the preset current threshold, the position corresponding to the laser spot of the high-flux pulsed laser on the perovskite semiconductor single crystal detector is used as the defect distribution position of the perovskite semiconductor single crystal detector.

[0043] This invention simulates the high-flux and single-photon irradiation modes found in nuclear radiation detection scenarios to achieve spatial uniformity imaging of the response to a single pulse excitation. Equipped with a frequency-tunable pulse laser and a high-precision displacement platform, it scans the perovskite semiconductor single crystal detector at a microscale. Combined with a single-pulse signal test module and an electrical performance test module, it records the photocurrent and pulse signal response at different locations in real time, forming a response distribution image for defect imaging and performance screening in the crystal. Ultimately, this allows for visual evaluation of device response uniformity and carrier transport performance, providing a basis for correlating defects with carrier transport performance and screening high-performance detectors.

[0044] In an embodiment of the present invention, it is further provided with: The beam splitting slot is provided between the spatial optical path device and the objective lens focusing system, and is coaxial with the exit surface of the spatial optical path device, the objective lens focusing system and the quartz window; The light intensity recording module based on silicon photodiode is integrated into the beam splitting slot and communicates with the data acquisition module. It is used to record the reflected light intensity of the perovskite semiconductor single crystal detector in real time, and to perform real-time imaging in the data acquisition module to obtain a light intensity distribution image.

[0045] This embodiment incorporates a beam splitter slot between the spatial optical path and the objective lens focusing system, and integrates a light intensity acquisition module 22 for synchronously recording the light intensity reflected from the detector surface during scanning, thereby acquiring surface topography information. The core of the light intensity acquisition module is a silicon photodiode with gain adjustment from 0dB to 100dB. The light intensity data is read by the data acquisition module and imaged in real time.

[0046] In the embodiment of the present invention, a temperature control platform 10 is further provided, which is arranged between the upper surface of the stage and the lower surface of the perovskite semiconductor single crystal detector to control the test temperature in the electromagnetic shielding box.

[0047] Specifically, the temperature control platform can be equipped with a variety of temperature control methods, such as semiconductor refrigeration, to characterize the correlation between defects and photoelectric responses at different temperatures.

[0048] The defect identification device based on imaging of a perovskite semiconductor single crystal detector described in the present invention is based on a frequency-adjustable pulsed laser and a two-dimensional displacement platform. It uses a pulsed laser with a very small laser spot as an excitation source, which can be focused on a point on the semiconductor crystal detector to observe the photoelectric response of the point. At the same time, with the help of the displacement platform, the position of the semiconductor crystal detector is moved so that the laser spot can scan the entire area, thereby obtaining the photoelectric response signal of this area, and recording the signal response at different positions in real time to form a response distribution imaging, thereby identifying the defect position in the crystal. This application realizes micro-area scanning of the detector based on the signal response of each point in the detector to be scanned when excited by the laser spot. It can accurately characterize the relationship between local defects and photoelectric response uniformity in the perovskite semiconductor single crystal detector, reveal local response differences, and thus determine whether the detector has defects based on whether the response is uniform, thereby realizing local defect identification, which is conducive to selecting defect-free perovskite semiconductor single crystal detectors for nuclear radiation detection applications, achieving uniform response, and thus improving radiation imaging accuracy.

[0049] Based on the above embodiment, in this embodiment, the connection relationship of the defect recognition device based on the imaging of the perovskite semiconductor single crystal detector of this embodiment is expressed as follows: the perovskite semiconductor single crystal detector 5 is placed in an electromagnetic shielding box 6, and a quartz window 4 is set above it; 1 is a visualization camera, which can realize imaging observation of the perovskite semiconductor single crystal detector 5 through the spatial optical path 2, the objective lens focusing system 3, and the quartz window 4; 8 is a picosecond laser, 7 is a laser controller for adjusting the repetition frequency of the pulsed laser; 9 is an attenuation plate for adjusting the intensity of the incident laser; the pulsed laser is input through the spatial optical path 2 and the objective lens focusing system 3 The light is incident on the surface of the detector 5 through the viewing window 4; 10 is a temperature control system, which is used to meet testing requirements at different temperatures; the stage 11 is placed on a high-precision two-dimensional displacement platform 12; the detector 5 is connected to the external circuit or grounded via the ground port 13, current output port 14, and voltage input port 15 in the electromagnetic shielding box; 15 is the output port for the induced signal in the pulse signal testing mode; the objective lens focusing module 3, electromagnetic shielding box 6, perovskite semiconductor single crystal detector 5, temperature control system 10, stage 11, and high-precision displacement platform 12 are all placed in a light shielding device 16 to prevent stray light from interfering with the measurement. In the low-flux pulse signal scanning imaging mode, voltage is applied to the detector via the high-voltage module 17, and its induced signal enters the pulse signal analysis and processing module 18. In the high-flux photocurrent integration scanning imaging mode, voltage is applied to the detector 8 via the electrical testing module 21, and its current information is collected. The data acquisition module 19 can read the waveform data from the oscilloscope in the pulse signal analysis and processing module 18 or the current information from the electrical testing module 21. The control module 20 controls the high-precision two-dimensional displacement platform 12 through the data acquisition module and acquires its position information, enabling real-time imaging during the scanning process. The data acquisition module 19 controls the voltage output of the electrical testing module 21. The light intensity recording module 22 is used to synchronously record the light intensity reflected from the detector surface during the scanning process to obtain surface topography information.

[0050] Based on the above embodiment, in this embodiment, a low-flux pulse signal scanning imaging test is performed using the defect recognition device based on perovskite semiconductor single crystal detector imaging provided by the present invention, including: S201: placing the detector on the stage of the electromagnetic shielding box, connecting the bottom electrode of the detector to port 15, and connecting the top electrode to port 13 for grounding; S202: Turn on the visualization camera, adjust the objective lens focusing system to an appropriate magnification, and focus on the detector surface; control the movement of the displacement platform through the control module, determine the starting point and end point of the detector scanning area, and record them in the data acquisition module; S203: Select a laser with a suitable wavelength, turn on the laser controller 7, and adjust its light output frequency to below 2 kHz to test the single pulse response of the device under low flux. Further observe the objective lens to focus the detector surface. It should be noted that the size of the laser spot incident on the detector surface can be adjusted within the range of 1 μm to 50 μm by adjusting the magnification of the objective lens, and can be adjusted comprehensively in combination with the scanning area size and scanning step size. S204: A positive voltage is applied to the bottom of the detector via port 15 by the high-voltage module 17, while the top electrode is grounded via port 13, establishing a vertical electric field. The incident laser excites the semiconductor material, generating electron-hole pairs. Due to the shallow depth of the laser, electron-hole pairs are primarily generated on the detector surface. Under the influence of the applied electric field, the holes are quickly collected by the top cathode, while the electrons drift toward the bottom anode, generating an induction signal between the electrodes. S205: The sensing signal enters the pulse signal analysis and processing module 18, firstly, it is generated into a pre-amplifier pulse signal by the first amplifying unit 181, and then further amplified by the second amplifying unit 182 to generate a main amplification pulse signal, and is displayed in real time on the oscilloscope in the pulse signal analysis submodule 183; Figure 6 FIG. 1 is a schematic diagram of the pulse signal output during the low-flux pulse signal scanning imaging test; S206: After confirming that the pulse signal is outputting normally, the two-dimensional displacement stage control unit in control module 20 is activated and the movement step size is set. The digital acquisition module 19, in conjunction with control module 20, controls the high-precision two-dimensional displacement stage, accurately scanning different locations of the device and synchronously recording position information. It also displays real-time imaging data of the preamplifier pulse signal amplitude V1, the main amplifier pulse signal amplitude V2, and the preamplifier pulse signal rise time. It also generates a pulse amplitude distribution histogram within the acquired area for observing energy spectrum broadening.

[0051] Reference Figure 7 As shown, it is the imaging diagram of the amplitude of the preamplifier pulse signal or the main amplifier pulse signal; refer to Figure 8 The figure shows the rise time imaging diagram of the preamplifier pulse signal; refer to Figure 9 As shown in the figure, it is a pulse amplitude distribution histogram. Since the induced signal is mainly generated by the drift of electrons in the electric field, by comparing parameters such as signal amplitude and rise time at different positions, the influence of local defects on electron transport performance and photoelectric response can be analyzed.

[0052] S207: Further changing the bias voltage applied to the detector can obtain imaging data of the preamplifier pulse signal amplitude V1 or the main amplifier pulse signal amplitude V2 under different bias voltages. Based on the signal amplitude information at different bias voltages at each position, the mobility lifetime product μτ imaging of electrons at different positions can be obtained by fitting according to the single-carrier Hecht equation, which is expressed as: ; in, is the collection efficiency, the mean drift free path of electrons , the mean drift free path of holes , is the position of the incident light, is the thickness of the device; and are the amount of charge collected and the theoretical amount of charge generated by the perovskite semiconductor single crystal detector, is the electric field intensity applied to the perovskite semiconductor single crystal detector; in the fitting process, is the amplitude V1 of the preamplifier pulse signal or the amplitude V2 of the main amplifier pulse signal of the first amplifying unit or the second amplifying unit under different bias voltages.

[0053] S208: Based on the rise time information of the preamplifier pulse signal under different bias voltages, the spatial distribution image of the electron mobility μ in the perovskite crystal can be obtained by fitting based on the following Hecht equation: ; in, is the bias voltage applied to the detector, is the thickness of the device, is the rise time of the preamplifier pulse signal under different bias voltages; S209: From the electron mobility lifetime product μτ and the mobility μ spatial distribution image, a distribution image of the carrier lifetime τ can be further obtained.

[0054] Reference Figure 10 As shown, it is the mobility distribution image of electrons at different positions; refer to Figure 11 As shown, it is the lifetime distribution image of electrons at different positions; refer to Figure 12 As shown, it is the mobility lifetime distribution image of electrons at different positions.

[0055] Based on the above description, this embodiment changes the laser incident surface by inverting the detector structure, or applies a negative voltage to the bottom of the detector (the top is grounded), and uses the same scanning method to obtain hole-dominated transport performance imaging, thereby comprehensively evaluating the spatial transport characteristics of electrons and holes and their correlation with material defects.

[0056] Based on the above embodiment, in this embodiment, a high-throughput photocurrent integral scanning imaging test is performed using the defect recognition device based on perovskite semiconductor single crystal detector imaging provided by the present invention, including: S301: placing a detector on a stage of an electromagnetic shielding box, connecting the anode of the detector to port 15 and further to the voltage output terminal of the electrical test module, and connecting the cathode of the detector to port 14 and further to the current input terminal of the electrical test module; S302: Turn on the visualization camera, adjust the objective lens focusing system to an appropriate magnification, and focus on the detector surface; control the movement of the displacement platform through the control module, determine the starting and ending points of the detector scanning area, and record them in the data acquisition module; S303: Select a laser with an appropriate wavelength, turn on the laser controller 7, and adjust its light output frequency to above 1 MHz to simulate the photocurrent response under high flux. Further observe the objective lens to focus the upper surface of the detector. Similarly, the laser spot size incident on the detector surface can be adjusted within the range of 1 μm to 50 μm by adjusting the objective lens magnification. This can be adjusted in combination with the scanning area size and scanning step size. S304: Apply a positive voltage to the bottom electrode of the detector through port 15 using the electrical test module to establish a vertical electric field and collect the current signal of the top electrode of the detector, including: S304-1: In the light-shielding mode, the data acquisition module is used to programmatically adjust the voltage V applied to the detector and collect currents at different voltages to obtain the IV characteristic curve of the entire detector. S304-2: Turn on the laser. High-flux laser light irradiates the semiconductor material, generating a large number of electron-hole pairs. Due to the shallow depth of the laser, electron-hole pairs are mainly generated on the detector surface. Under the action of the external electric field, the holes are quickly collected by the top cathode, and a large number of electrons drift to the bottom anode, forming a photocurrent. S304-3: In the light-on mode, the voltage V applied to the detector is adjusted by the program, and the current at different voltages is collected to obtain the IV characteristic curve of the entire detector under light excitation; S304-4: In laser-off mode, a fixed voltage is used to record the curve of the detector dark current over time through the data acquisition module. By manually or programmatically controlling the laser on and off, the light response It curve can be obtained, and then the net photocurrent ΔI can be obtained. S305: After confirming that the photocurrent signal is being output correctly, the displacement stage control unit in control module 20 is activated and the movement step size is set. Control module 20, through digital acquisition module 19, controls the high-precision two-dimensional displacement stage, accurately scanning different locations of the device and synchronously recording position information. It also displays real-time imaging data of photocurrent ΔI.

[0057] Reference Figure 13The following figure shows the imaging results output in high-flux photocurrent integration scanning mode. By further varying the bias voltage applied to the detector, the photocurrent at different bias voltages can be obtained. Based on the photocurrent information at each position under different bias voltages, the mobility lifetime product μτ of electrons at different positions can be fitted using the single-carrier Hecht equation.

[0058] Similarly, this embodiment changes the laser incident surface by inverting the detector structure, or applies a negative voltage to the bottom of the detector (the top is grounded), and adopts the same scanning method to obtain a photocurrent response image dominated by hole transport.

[0059] This invention provides an imaging method with high spatial resolution and quantitative analysis capabilities for characterizing and studying the photoelectric response uniformity of perovskite semiconductor single-crystal detectors under both high-flux photocurrent integration and low-flux pulse signal operating modes in nuclear radiation detection scenarios. Compared to existing technologies, this method uses a frequency-tunable pulsed laser to simulate high-flux and single-photon irradiation scenarios. Through micro-area scanning, pulse signal testing, and electrical performance evaluation, it visualizes device response uniformity and carrier transport performance. It establishes a correlation between defects and photoelectric response under different detection scenarios, directly correlating this with the actual device performance (e.g., energy resolution and spatial resolution). Through micro-area scanning and imaging techniques, this method accurately characterizes the relationship between local defects and photoelectric response uniformity in perovskite semiconductor single-crystal detectors, improving the accuracy of defect analysis and providing a more precise basis for crystal and detector quality grading and troubleshooting. This invention is specifically developed for research into the correlation between defects and photoelectric response in perovskite semiconductors. It can provide critical feedback data for optimizing key process parameters during the growth of large-scale perovskite crystals, driving continuous improvements in crystal preparation and device processing, thereby significantly enhancing material quality and detection performance. This system will provide strong support for the design optimization and large-scale application of a new generation of high-performance perovskite nuclear radiation detectors. The widespread application of this defect identification device is expected to significantly improve the overall performance stability, photoelectric response uniformity, and imaging spatial resolution of perovskite nuclear radiation detectors, providing higher-precision and more reliable detection solutions for fields such as nuclear medicine imaging, industrial nondestructive testing, and environmental monitoring.

[0060] Based on the above embodiment, in this embodiment, a defect identification device based on imaging of a perovskite semiconductor single crystal detector provided by the present invention is used to perform high-throughput photocurrent integration scanning on a detector made of a cesium lead bromine crystal. The specific steps include: S401: Cut the melt-grown cesium lead bromine crystal into 6 mm × 6 mm × 3 mm pieces, polish and etch them, and deposit Au and Cu electrodes on their upper and lower surfaces, respectively, to prepare a detector; S402: Analyze the response uniformity of the entire detector in high-flux photocurrent integration scanning mode. Place the detector on the system's stage, connect the bottom Au electrode to the high-voltage output of the electrical test module, and connect the top Cu electrode to the current input port of the electrical test module. S403: Turn on the visualization camera and objective lens focusing system and focus on the detector surface. Control the movement of the motorized translation stage to ensure that the scanning area includes the entire detector range. Set the start and end points of the scanning area and record them in the data acquisition module. Set the scanning step size of the displacement stage to 50μm. S404: Apply voltage to the bottom electrode of the detector through the electrical test module, set the voltage change through the data acquisition module, and record the dark current to obtain its IV curve; Figure 14 FIG. 4 shows an IV curve of a detector made of cesium lead bromine crystal; S405: Turn on the 482nm pulsed laser, adjust its repetition rate to 10MHz, set the objective lens magnification to 20x, and adjust the objective lens focusing system so that the laser spot is focused on the detector surface. Use the control module to adjust the displacement platform to position the laser spot at the starting point of the scanning area. S406: Set a negative bias voltage of 10V on the Au electrode at the bottom of the detector through the electrical test module, and manually control the on and off of the laser to record the current at different times to obtain its It curve; refer to Figure 15 The figure shows the It curve of the detector made of cesium lead bromine crystal; S407: Use the control module to adjust the displacement stage, position the laser spot at the starting point of the scanning area, and set the detector voltage to -100V. Click Start to start the 2D displacement stage scanning. Simultaneously, open the light intensity recording module. The data acquisition module provides real-time images of the photocurrent distribution and the light intensity distribution reflected from the detector surface.

[0061] Reference Figure 16 As shown, this is the photocurrent distribution image of the detector made of cesium lead bromine crystal; it can be seen from the photocurrent distribution image that the overall response of the detector is uniform, and the response of some areas in the upper left corner is poor.

[0062] Reference Figure 17 The image shown here shows the intensity distribution of light reflected from the surface of a detector made of a cesium lead bromine crystal. This image reflects the detector's surface topography, showing a uniform surface. The Ag glue and its connected copper wire can be seen in the lower left corner. Analysis of the intensity distribution of light reflected from this area reveals a relatively intact surface, with cracks on the left side. Therefore, the poor response is likely due to surface and internal crack defects in the detector crystal.

[0063] Based on the above embodiment, in this embodiment, a defect recognition device based on imaging of a perovskite semiconductor single crystal detector provided by the present invention is used to perform low-flux pulse signal scanning on a detector made of a cesium lead bromine crystal. The specific steps include: S501: Pulse signal scanning test of a local area of ​​the detector crystal. The detector is placed on the stage of the system, the bottom electrode is connected to the high voltage input port 15, and the top electrode is grounded; S502: Turn on the visualization camera and the objective lens focusing system to focus on the detector surface. Control the movement of the motorized translation stage to ensure that the scanning area includes the entire detector range. Set the start and end points of the scanning area and record them in the data acquisition module. Set the scanning step size of the displacement stage to 50μm. S503: Turn on the 482nm pulsed laser, adjust its repetition rate to 1kHz, set the objective lens magnification to 20x, and adjust the objective lens focusing system so that the laser spot is focused on the detector surface. Use the control module to adjust the displacement platform to position the laser spot at the starting point of the scanning area. S504: Apply a 30V negative voltage to the Au electrode at the bottom of the detector and observe the preamplifier pulse signal and the main amplifier pulse signal in the pulse signal analysis module to ensure that they are output normally; S505: Click Start to start scanning. The displacement stage begins scanning, and the data acquisition module provides a real-time image of the main amplifier pulse amplitude distribution. By changing the voltage, pulse amplitude distribution images under different bias voltages can be obtained, and a histogram of the detector's pulse signal amplitude distribution can be obtained.

[0064] Reference Figure 18 As shown, it is the pulse signal amplitude distribution image of the low-flux pulse signal scanning imaging test perovskite cesium lead bromine detector; Figure 19 Figure 2 shows the pulse signal amplitude distribution histogram of a perovskite cesium lead bromine detector tested using low-flux pulse signal scanning imaging. The pulse signal amplitude distribution varies widely, with the detector response being non-uniform within the 1-3V range. The pulse signal is weaker in cracked areas, indicating a negative impact on carrier transport and collection. Furthermore, the "line-like" distribution with low pulse signal amplitude may be due to impaired charge collection caused by micro-scratches left over from the surface treatment process. These micro-scratches may hinder carrier migration across the device surface, thus affecting effective charge collection.

[0065] Based on the above embodiment, in this embodiment, the defect recognition device based on imaging of a perovskite semiconductor single crystal detector provided by the present invention is used to perform detection imaging on a detector made of a cesium lead bromine crystal. The specific steps include: S601: Cut a melt-grown cesium lead bromide crystal into a 5 mm × 5 mm × 2 mm cuboid. The crystal surface is mechanically polished using 1000, 5000, and 12000 grit sandpaper to remove damage from the cutting process. The polished crystal is then cleaned with toluene to remove any remaining contaminants. Bismuth and gold electrodes are deposited on the upper and lower surfaces of the crystal, respectively, using thermal evaporation, each with a thickness of 50 nm. S602: Place the detector on the stage of the system, with the Au electrode at the bottom connected to the high voltage input port 15, and the Bi electrode at the top grounded; S603: Turn on the visualization camera and objective lens focusing system to focus on the detector surface. Move the displacement stage to determine a scanning area of ​​100 μm × 100 μm. Set the start and end points of the scanning area and record them in the data acquisition module. Set the scanning step size of the displacement stage to 2 μm. S604: Turn on the 482nm pulsed laser, adjust its repetition rate to 1kHz, set the objective lens magnification to 20x, and adjust the objective lens focusing system so that the laser spot is focused on the detector surface. Use the control module to adjust the displacement platform to position the laser spot at the starting point of the scanning area. S605: Apply a 100V negative voltage to the bottom of the detector and observe the preamplifier pulse signal and main amplifier pulse signal in the pulse signal analysis module to ensure their normal output; S606: Click Start to start the acquisition, and the displacement platform begins scanning. The distribution image of the main amplification pulse amplitude can be obtained in real time in the data acquisition module; Reference Figure 20 The figure shows the pulse signal distribution image of the detector prepared from the perovskite crystal after only mechanical polishing. In the scanning area, the pulse signal amplitude distribution varies greatly, showing a large number of "line-like" distributions with low pulse signal amplitudes. This is because the surface with only mechanical polishing has a large number of scratches, resulting in uneven surface Bi electrode deposition and impaired charge collection. S607: After mechanically polishing the surface of the same crystal, it is etched to remove surface scratches and the detector is re-prepared. The same scanning conditions are used to perform pulse signal amplitude scanning imaging to finally obtain the detector distribution. Figure 21 As shown, this is the pulse signal distribution image of the detector prepared from the perovskite crystal after mechanical polishing and chemical etching; compared with the unetched crystal, its pulse signal uniformity is significantly improved, indicating that chemical etching can effectively reduce surface scratches.

[0066] The testing method of this embodiment can provide theoretical guidance for the surface treatment of novel perovskite crystals and the optimization of device preparation processes.

[0067] This invention aims to provide a device for testing the spatial uniformity of the photoelectric response of perovskite semiconductor single-crystal detectors using single-pulse excitation imaging. Based on a frequency-adjustable single-pulse laser source and a high-precision displacement platform, the device can test the photocurrent response and pulse signal response images of perovskite semiconductor single-crystal detectors in both high-flux photocurrent integration and low-flux pulse signal operating modes. The system supports testing under multiple bias conditions and can further calculate the spatial distribution of carrier mobility-lifetime products (μτ values), mobility (μ), and lifetime (τ). Based on these imaging data, the correlation between material defect distribution and carrier transport performance can be deeply analyzed and revealed, providing a reliable basis for quality assessment, crystal growth processing, and device fabrication process optimization of perovskite semiconductor single-crystal detectors.

[0068] The defect identification device based on imaging of a perovskite semiconductor single crystal detector described in the present invention is based on a frequency-adjustable pulsed laser and a two-dimensional displacement platform. It uses a pulsed laser with a very small laser spot as an excitation source, which can be focused on a point on the semiconductor crystal detector to observe the photoelectric response of the point. At the same time, with the help of the displacement platform, the position of the semiconductor crystal detector is moved so that the laser spot can scan the entire area, thereby obtaining the photoelectric response signal of this area, and recording the signal response at different positions in real time to form a response distribution imaging, thereby identifying the defect position in the crystal based on the signal intensity in the response distribution imaging. This application realizes micro-area scanning of the detector based on the signal response of each point in the detector to be scanned when excited by the laser spot. It can accurately characterize the relationship between local defects and photoelectric response uniformity in the perovskite semiconductor single crystal detector, reveal local response differences, and thus determine whether the detector has defects based on whether the response is uniform, thereby realizing local defect identification, which is conducive to selecting defect-free perovskite semiconductor single crystal detectors for nuclear radiation detection applications, achieving uniform response, and thus improving radiation imaging accuracy. The defect identification device of the present invention is based on the imaging of perovskite semiconductor single crystal detectors. When performing detector photoelectric response signal imaging, it includes high-flux photocurrent integral scanning imaging and low-flux pulse signal scanning imaging. It can simulate high-flux and single-photon irradiation scenarios in nuclear radiation detection scenarios. Based on single-pulse excitation spatial response uniformity imaging, it can further perform a visual evaluation of response uniformity and carrier transport performance, providing a basis for the correlation between defects and carrier transport performance, and the screening of high-performance detectors.

[0069] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware. Furthermore, the present application may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0070] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0071] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will appreciate that other variations or modifications can be made based on the above description. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. A defect recognition device based on imaging of a perovskite semiconductor single crystal detector, characterized in that: include: A light-shielding device, which is provided with: Objective lens focusing system; The electromagnetic shielding box has a quartz window on the top, a grounding port, a current output port, and a voltage input port on the side, and contains: 2D mobile platform; A stage is provided on the upper surface of the two-dimensional moving platform and is used to place a perovskite semiconductor single crystal detector; The top electrode of the perovskite semiconductor single crystal detector is connected to the ground port or the current input terminal, and the bottom electrode is connected to the voltage input terminal; The visualization camera focuses on the perovskite semiconductor single crystal detector through the first incident surface of the spatial optical path device, the objective lens focusing system and the quartz window, and obtains the starting point and end point of the area to be scanned of the perovskite semiconductor single crystal detector; After obtaining the starting point and end point of the area to be scanned, the pulsed laser focuses the laser spot on the perovskite semiconductor single crystal detector through the attenuation plate, the second incident surface of the spatial optical path device, the objective lens focusing system, and the quartz window, so that the laser spot scans from the starting point to the end point of the area to be scanned while the control module controls the two-dimensional moving platform to move at a preset step size; A test module, one end of which is connected to the bottom electrode of the perovskite semiconductor single crystal detector through a voltage input terminal. When the laser spot reaches the starting point of the area to be scanned, a voltage is applied to the perovskite semiconductor single crystal detector, causing the perovskite semiconductor single crystal detector to generate a vertical electric field and generate a response signal during the micro-area scanning process. The response signal is converted into a test signal, and a distribution image of the test signal is obtained, so as to obtain the defect distribution position of the perovskite semiconductor single crystal detector based on the distribution image of the test signal; Among them, the output surface of the visualization camera and the first incident surface of the spatial optical path device are coaxial; the pulse laser, the attenuation plate, and the second incident surface of the spatial optical path device are coaxial; the output surface of the spatial optical path device, the objective lens focusing system and the quartz window are coaxial.

2. The defect recognition device based on perovskite semiconductor single crystal detector imaging according to claim 1, characterized in that: The control module controls the two-dimensional mobile platform to move with a preset step size, including: Get the starting coordinates of the area to be scanned of the perovskite semiconductor single crystal detector captured by the visualization camera and the end point coordinates , and preset the step size 、 ; Control the two-dimensional mobile platform to carry the perovskite semiconductor single crystal detector on the stage to move so that the laser spot is located at the starting point of the area to be scanned, and move along the x-axis in the row where the starting point is located according to the step size. Move and perform micro-area scanning at each point to be scanned until the laser spot reaches , the line is scanned; Control the two-dimensional mobile platform to carry the perovskite semiconductor single crystal detector on the stage to move so that the laser spot returns along the x-axis direction Then, step along the y-axis , perform micro-area scanning on the points to be scanned in the current row in sequence until stepping along the y-axis direction The y-axis coordinate after is greater than , completing the process of the laser spot scanning from the starting point to the end point of the area to be scanned.

3. The defect recognition device based on perovskite semiconductor single crystal detector imaging according to claim 1, characterized in that: When the pulse laser outputs low-flux pulse laser, the test module is a pulse signal test module, including: A high-voltage module, one end of which is connected to the bottom electrode of the perovskite semiconductor single crystal detector through the voltage input terminal, and a positive voltage is applied to excite the perovskite semiconductor single crystal detector to generate electron-hole pairs, and the holes are collected by the top cathode, and the electrons drift to the bottom anode, thereby generating an induction signal between the top electrode and the bottom electrode of the perovskite semiconductor single crystal detector; The pulse signal analysis and processing module has one end connected to the bottom electrode of the perovskite semiconductor single crystal detector through the voltage input end, obtains the sensing signal and converts it into oscilloscope data as the test signal output of the test module.

4. The defect recognition device based on perovskite semiconductor single crystal detector imaging according to claim 3, characterized in that: Based on the distribution image of the test signal, the defect distribution position of the perovskite semiconductor single crystal detector is obtained, including: Based on the test signal, the main amplifier pulse signal is collected in real time to construct a pulse amplitude distribution diagram; Based on the pulse amplitude distribution diagram, the position corresponding to the laser spot of the low-flux pulsed laser on the perovskite semiconductor single crystal detector when the pulse amplitude is not greater than the preset amplitude threshold is used as the defect distribution position of the perovskite semiconductor single crystal detector.

5. The defect recognition device based on perovskite semiconductor single crystal detector imaging according to claim 3, characterized in that: Pulse signal analysis and processing module, including: The first amplifying unit has an input end connected to the bottom electrode of the perovskite semiconductor single crystal detector through the voltage input end on the electromagnetic shielding box to obtain the sensing signal and generate a preamplifier pulse signal output; The second amplifying unit, whose input end is connected to the output end of the first amplifying unit, obtains the pre-amplifier pulse signal and generates the main amplifying pulse signal output; a pulse waveform analysis submodule, the input end of which is connected to the output end of the first amplifying unit and the output end of the second amplifying unit, and uses an oscilloscope to display amplitude information in real time as oscillographic data based on the preamplifier pulse signal and the main amplifier pulse signal; Alternatively, the multi-channel pulse signal analysis submodule, whose input end is connected to the output end of the second amplifying unit, classifies the pulse amplitudes of the main amplified pulse signal by channel address and generates amplitude histogram distribution information as oscillographic data.

6. The defect recognition device based on perovskite semiconductor single crystal detector imaging according to claim 1, characterized in that: When the pulse laser outputs high-flux pulse laser, the test module is a photocurrent integral signal test module, including: An electrical test module, one end of which is connected to the bottom electrode of the perovskite semiconductor single crystal detector through the voltage input end; by applying a positive voltage to the bottom electrode of the perovskite semiconductor single crystal detector, the perovskite semiconductor single crystal detector is excited to generate electron-hole pairs, and the holes are collected by the top cathode, and the electrons drift to the bottom anode, thereby generating an induction signal between the electrodes and generating a vertical electric field; one end of which is connected to the top electrode of the perovskite semiconductor single crystal detector through the current output end, and the photocurrent signal of the top electrode is collected by using the current output end.

7. The defect recognition device based on imaging of a perovskite semiconductor single crystal detector according to claim 6, characterized in that: Based on the distribution image of the test signal, the defect distribution position of the perovskite semiconductor single crystal detector is obtained, including: Record photocurrent signals in real time and generate photocurrent distribution images; Based on the photocurrent distribution image, the position corresponding to the laser spot of the high-flux pulsed laser on the perovskite semiconductor single crystal detector when the current value in the photocurrent distribution image is not greater than the preset current threshold is used as the defect distribution position of the perovskite semiconductor single crystal detector.

8. The defect identification device based on imaging of a perovskite semiconductor single crystal detector according to claim 1, characterized in that: Also includes: The beam splitting slot is provided between the spatial optical path device and the objective lens focusing system, and is coaxial with the exit surface of the spatial optical path device, the objective lens focusing system and the quartz window; The light intensity recording module based on silicon photodiode is integrated into the beam splitting slot and communicates with the data acquisition module. It is used to record the reflected light intensity of the perovskite semiconductor single crystal detector in real time, and to perform real-time imaging in the data acquisition module to obtain a light intensity distribution image.

9. The defect recognition device based on perovskite semiconductor single crystal detector imaging according to claim 1, characterized in that: The perovskite includes three-dimensional perovskite, two-dimensional perovskite, zero-dimensional perovskite and antiperovskite; The three-dimensional perovskite is selected from A1B1X13; wherein A1 is selected from one or more of Na, K, Rb, Cs, Cu, Tl and H3O, B1 is selected from one or more of Pb, Si, Ge, Sn, Mg, Ca, Sr, Ba, Zn, Cd and Hg, and X1 is selected from one or more of F, Cl, Br, I, BF4, HCOO, OH, CN, SCN, NCS, SH, NO3 and H2POO; The two-dimensional perovskite is selected from TlPbI3 or A23B22X29; wherein A2 is selected from one or both of Cs and Rb, B2 is selected from one or both of Sb and Bi, and X2 is selected from one or more of F, Cl, Br and I; The zero-dimensional perovskite is selected from Cs3Bi2I9, Cs2TeI6, Cs2TeBr6 or Cs2TeCl6; The antiperovskite is selected from Hg3Se2Br2 or TlSn2I5.

10. The defect recognition device based on perovskite semiconductor single crystal detector imaging according to claim 1, characterized in that: Also includes: The temperature control platform is arranged between the upper surface of the stage and the lower surface of the perovskite semiconductor single crystal detector to control the test temperature in the electromagnetic shielding box.

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