Focal plane wide-spectrum detector

Abstract

The present disclosure relates to a focal plane wide spectrum detector, which comprises a pixel region and a peripheral region located at least one side of the pixel region, the pixel region is provided with an array of detection pixels; the focal plane wide spectrum detector further comprises a readout circuit substrate and a grid common electrode, a center electrode and a photosensitive material layer located at the same side of the readout circuit substrate; the readout circuit substrate comprises a common electrode located at the peripheral region; the grid common electrode is connected to the common electrode; the grid common electrode comprises an array of lattices in the pixel region, each lattice corresponds to a detection pixel, and each lattice extends out a branch electrode; the center electrode is correspondingly arranged in the lattice of the detection pixel and is electrically connected to the readout circuit substrate, the center electrode is electrically insulated from the grid common electrode, and the center electrode is at least partially arranged opposite to the branch electrode; and the photosensitive material layer is at least filled between the center electrode and the branch electrode. Thus, the response uniformity of the device is improved.

Description

Technical Field

[0001] This disclosure relates to the field of photoelectric detection technology, and in particular to a focal plane broadband detector. Background Technology

[0002] Photoelectric detection, such as infrared imaging, plays a crucial role in military reconnaissance, remote sensing mapping, and aerospace. Current mid-wave infrared focal plane arrays primarily utilize bulk semiconductor materials such as mercury cadmium telluride, type-II superlattices, and indium antimonide, which exhibit excellent performance and high stability. However, the complex material preparation and flip-chip bonding processes limit the mass production and low-cost application of bulk semiconductor focal plane arrays. Colloidal quantum dots, as an emerging liquid semiconductor material, possess tunable band gaps, allowing for adjustment of absorption and response spectra by modifying size and shape. Due to surface effects, quantum dots exhibit a large specific surface area, resulting in high quantum efficiency and carrier lifetime. They also offer advantages such as a wide spectral tuning range, large-scale synthesis, low preparation cost, and easy processing, providing significant design and control freedom for quantum dot-based devices and offering novel approaches to the development of new infrared focal plane arrays. These emerging materials, currently the subject of much research, have wide applications in optoelectronics, sensing, biomedicine, displays, energy, photocatalysis, electronics, and communications.

[0003] Silicon-based CMOS (Complementary Metal-Oxide Semiconductor) readout circuit substrate-compatible quantum dot technology has always been a research hotspot. The unique liquid-phase synthesis characteristics of colloidal quantum dots enable monolithic integration on silicon, avoiding the complex alignment and flip-chip bonding processes in flip-chip bonding. CCD (Charge-Coupled Device) chips first appeared in 1970, with Boyle and Smith of Bell Labs proposing the concept. With the continuous development of semiconductor technology, CCD technology has become dominant in imaging devices. Because CCDs only have one (or a few) output nodes for unified readout, a wide signal bandwidth of the output amplifier is required to read the entire image signal, and inter-pixel interference is very severe, with noise significantly affecting image quality. As array size increases and pixel size decreases, the problem of large crosstalk in large-area CCD imaging sensors becomes increasingly acute, affecting the device's signal-to-noise ratio and imaging quality. The basic imaging process of CMOS also consists of three steps: charge generation, charge quantization, and signal output. It differs from CCD in that it uses different methods and mechanisms to achieve these functions. In CMOS chips, each pixel has its own signal amplifier to perform charge-to-voltage conversion. The bandwidth requirement of the amplifier in each pixel is low, which greatly reduces the power consumption of the chip, effectively prevents imaging interference and reduces device noise, and overcomes the severe limitations of CCD devices for large array signal crosstalk.

[0004] In related technologies, in the quantum dot integrated silicon-based CMOS technology, the functional film layers in photodetectors are usually stacked along the direction perpendicular to the substrate. When fabricating large arrays, the precision of spin coating and scraping equipment can affect the formation of uniform film layers of consistent thickness on the large array substrate, which in turn leads to inconsistent effective volume of the device and increased non-uniformity of device response. Summary of the Invention

[0005] To solve the above-mentioned technical problems, or at least partially solve them, this disclosure provides a focal plane broadband detector.

[0006] This disclosure provides a focal plane broadband detector, including: a pixel region and a peripheral region located on at least one side of the pixel region, wherein the pixel region is provided with an array of detector pixels;

[0007] The focal plane broadband detector also includes:

[0008] Read out the circuit substrate, including the common ground electrode located in the peripheral region;

[0009] A grid common ground electrode is located on one side of the readout circuit substrate and connected to the common ground electrode; the grid common ground electrode includes an array of grids in the pixel area, each grid corresponding to a probe pixel, and a branch electrode extending from each grid;

[0010] The center electrode is located on the same side of the readout circuit substrate as the grid common ground electrode and is correspondingly disposed within the grid of the detection pixel. It is electrically connected to the readout circuit substrate. The center electrode is electrically insulated from the grid common ground electrode. The center electrode and the branch electrode are at least partially opposite each other.

[0011] A photosensitive material layer is filled at least between the central electrode and the branch electrode.

[0012] Optionally, at least some of the individual detection pixels include at least two photodiodes connected in parallel, and the corresponding individual detection pixel includes at least two photosensitive material layers with different response bands coupled in a planar manner.

[0013] Optionally, the grid common ground electrode further includes a plurality of first strip electrodes arranged along a first direction and a plurality of second strip electrodes arranged along a second direction, wherein the first strip electrodes and the second strip electrodes intersect to define the grid;

[0014] The branch electrodes of the grid common ground electrode include a first branch electrode and a second branch electrode arranged opposite to each other, and the first branch electrode and the second branch electrode are respectively connected to two adjacent first strip electrodes.

[0015] Optionally, the first branch electrode and the second branch electrode are parallel to each other along the second direction and are both parallel to the center electrode.

[0016] Optionally, the first branch electrode and the second branch electrode are located on the same side of the central electrode along the first direction and are opposite to a portion of the central electrode.

[0017] Optionally, a single detection pixel includes a first partition and a second partition, and the central electrode extends into the first partition and the second partition;

[0018] The photosensitive material layers with different response bands include a first photosensitive material layer and a second photosensitive material layer. The first photosensitive material layer fills the first partition, and the second photosensitive material layer fills the second partition.

[0019] Optionally, the photosensitive material layer includes an intrinsic quantum dot layer;

[0020] The central electrode and the grid common ground electrode are respectively one of an N-type material electrode and a P-type material electrode, and the two are different;

[0021] The intrinsic quantum dot layer is at least filled between the N-type material electrode and the P-type material electrode, and covers the side of the N-type material electrode and the P-type material electrode opposite to the readout circuit substrate.

[0022] Optionally, the focal plane broadband detector also includes:

[0023] The N-type quantum dot layer is located on the side of the N-type material electrode facing away from the readout circuit substrate, and is located between the readout circuit substrate and the intrinsic quantum dot layer;

[0024] And / or,

[0025] The P-type quantum dot layer is located on the side of the P-type material electrode away from the readout circuit substrate, and is located between the readout circuit substrate and the intrinsic quantum dot layer.

[0026] Optionally, the focal plane broadband detector also includes:

[0027] An electron transport layer is located between the N-type material electrode and the N-type quantum dot layer;

[0028] And / or,

[0029] A hole transport layer is located between the P-type material electrode and the P-type quantum dot layer.

[0030] Optionally, in this focal plane broadband detector, the thickness of the intrinsic quantum dot layer is 300 nanometers to 400 nanometers;

[0031] The thickness of the N-type material electrode is 20 nanometers to 40 nanometers;

[0032] The thickness of the P-type material electrode is 20 nanometers to 40 nanometers;

[0033] The thickness of the N-type quantum dot layer is 40 nanometers to 60 nanometers;

[0034] The thickness of the P-type quantum dot layer is 40 nanometers to 60 nanometers.

[0035] The technical solution provided in this disclosure has the following advantages compared with the prior art:

[0036] The focal plane broadband detector disclosed herein includes: a pixel region and a peripheral region located on at least one side of the pixel region, wherein the pixel region is provided with an array of detector pixels; the focal plane broadband detector further includes: a readout circuit substrate, including a common ground electrode located in the peripheral region; a grid common ground electrode located on one side of the readout circuit substrate and connected to the common ground electrode; the grid common ground electrode includes an array of grids in the pixel region, each grid corresponding to a detector pixel, and a branch electrode extending from each grid; a central electrode located on the same side of the readout circuit substrate as the grid common ground electrode and correspondingly disposed within the grid of the detector pixel, electrically connected to the readout circuit substrate, the central electrode being electrically insulated from the grid common ground electrode, and the central electrode and the branch electrodes being at least partially opposite to each other; and a photosensitive material layer at least filling the space between the central electrode and the branch electrodes. This provides a horizontally structured focal plane broadband detector, wherein the effective volume of the photodetector structure is determined based on the positions of the central electrode and the branch electrodes, thereby avoiding the influence of non-uniformity caused by the mismatch between pixel size and array scale and equipment processing precision during the fabrication of large-area arrays and ultra-large-area arrays, and improving the uniformity of device response. Attached Figure Description

[0037] The accompanying drawings, which are incorporated in and form a part of this specification, illustrate embodiments consistent with this disclosure and, together with the description, serve to explain the principles of this disclosure.

[0038] To more clearly illustrate the technical solutions in the embodiments of this disclosure or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0039] Figure 1 A schematic diagram of a planar structure of a focal plane broadband detector provided in an embodiment of this disclosure;

[0040] Figure 2 A schematic diagram of an equivalent circuit for another focal plane broadband detector provided in an embodiment of this disclosure;

[0041] Figure 3 A partially magnified schematic diagram of the detection pixel in another focal plane broadband detector provided in this embodiment of the present disclosure;

[0042] Figure 4 For along Figure 3 Schematic diagram of the cross-sectional structure between A1 and A2;

[0043] Figure 5 For along Figure 3 Schematic diagram of the cross-sectional structure between B1 and B2;

[0044] Figure 6 This is a schematic diagram illustrating the imaging application effect of a focal plane broadband detector provided in an embodiment of this disclosure. Detailed Implementation

[0045] To better understand the above-mentioned objectives, features, and advantages of this disclosure, the solutions disclosed herein will be further described below. It should be noted that, unless otherwise specified, the embodiments and features described herein can be combined with each other.

[0046] Numerous specific details are set forth in the following description in order to provide a full understanding of this disclosure, but this disclosure may also be implemented in other ways different from those described herein; obviously, the embodiments in the specification are only some, and not all, of the embodiments of this disclosure.

[0047] The focal plane broadband detector provided in this disclosure is a planar PV (photovoltaic) structure focal plane broadband detector with grid electrodes. Based on a quantum dot integrated silicon-based CMOS readout circuit substrate, it proposes a scheme for a horizontal PV structure focal plane broadband detector, and further proposes a scheme for a horizontally parallel PV structure focal plane broadband detector. This approach has the following advantages compared to devices based on vertical PV structures:

[0048] First, the pixel electrode (i.e., the center electrode) and the carrier transport layer (including the electron transport layer and the hole transport layer) can be fabricated using micro / nano fabrication photolithography etching processes. The P-type quantum dot layer, N-type quantum dot layer, and intrinsic quantum dot layer can be fabricated using at least one of inkjet printing, electrohydrodynamic printing, and nanoimprinting processes. Based on this, the fabrication of vertical PV structure devices in large arrays is affected by the precision of spin coating and scraping equipment, resulting in the inability to form a uniform film layer of consistent thickness on the large array substrate. This leads to inconsistent effective device volume and increased device response non-uniformity. However, the horizontal structure device architecture coupling method provided in this disclosure determines the effective device volume based on the center electrode and branch electrodes, and is less affected by the film layer thickness uniformity. Therefore, it can improve the aforementioned drawbacks of the vertical structure, avoiding the non-uniformity caused by the mismatch between pixel size and array scale and equipment processing precision during the fabrication of large and ultra-large arrays, thus improving device response uniformity.

[0049] Secondly, a single detection pixel (i.e., pixel device) can be composed of two photodiodes. The two photodiodes share the center electrode and the ground electrode, but the difference lies in the different response bands of the photosensitive material layer, thereby increasing the utilization rate of the electrodes. The two PV devices can be composed of quantum dot materials that detect different bands, thus broadening the detection spectrum of the device.

[0050] Third, it increases the contact area between the intrinsic quantum dot layer and the P-type and N-type quantum dot layers, which can widen the depletion layer width of the photodiode, thereby increasing the number of charge carriers and further improving the device response.

[0051] Fourth, from the perspective of device application, the parallel PV structure device in the embodiments of this disclosure can replace dual-lens cameras and other applications in related technologies. The functional unit of the dual-lens camera can be equivalently replaced by two PV devices located in the same detection pixel, which can realize the transformation from dual-lens to single-lens, reduce the size, power consumption and area of ​​the camera, and is conducive to the miniaturization of devices.

[0052] The focal plane broadband detector provided in the embodiments of this disclosure will be described exemplarily below with reference to the accompanying drawings.

[0053] For example, Figure 1 This is a schematic diagram of a planar structure of a focal plane broadband detector provided in an embodiment of this disclosure. (Reference) Figure 1 The focal plane broadband detector 10 may include a pixel region 101 and a peripheral region 102 located on at least one side of the pixel region 101, wherein the pixel region 101 is provided with an array of detector pixels 10P.

[0054] Pixel region 101 is a region for realizing photoelectric response, and can be provided with an array of detector pixels 10P; the detector pixels 10P are used to receive light signals and generate corresponding photoelectric signals based on photoelectric conversion in response to the received light signals. The peripheral region 102 is located on at least one side of pixel region 101, for example... Figure 1 The peripheral region 102 shown in the figure can surround the pixel region 101. The peripheral region 102 can be used to lay out lines for photoelectric signal transmission, as detailed below.

[0055] In this embodiment of the application, the focal plane broadband detector 10 further includes: a readout circuit substrate 11, a grid common ground electrode 12, a central electrode 13, and a photosensitive material layer 14.

[0056] The readout circuit substrate 11 includes a common ground electrode 110 located in the peripheral region 102; a grid common ground electrode 12 is located on one side of the readout circuit substrate 11 and connected to the common ground electrode 110; the grid common ground electrode 12 includes an array of grids 120 in the pixel region 101, each grid 120 corresponding to a detection pixel 10P, and a branch electrode 122 extending from each grid 120; a center electrode 13 is located on the same side of the readout circuit substrate 11 as the grid common ground electrode 12 and is correspondingly disposed in the grid 120 of the detection pixel 10P, electrically connected to the readout circuit substrate 11, the center electrode 13 is electrically insulated from the grid common ground electrode 12, and the center electrode 13 and the branch electrode 122 are at least partially opposite each other; a photosensitive material layer 14 is at least filled between the center electrode 13 and the branch electrode 122.

[0057] The grid common ground electrode 12, the central electrode 13, and the photosensitive material layer 14 are all located on the same side of the readout circuit substrate 11. The central electrode 13 is distributed within the grid 120 of the grid common ground electrode 12, and is at least partially opposite to the branch electrode 122 within the grid 120. The photosensitive material layer 14 is at least filled between the central electrode 13 and the branch electrode 122. The positions of the central electrode 13 and the branch electrode 122 within the detection pixel 10P determine the effective volume of the photoelectric detection structure. This avoids the influence of non-uniformity caused by the mismatch between pixel size and array scale and equipment processing accuracy when fabricating large-area arrays and ultra-large-area arrays, thereby improving the uniformity of device response.

[0058] In some embodiments, Figure 2 This is a schematic diagram of an equivalent circuit for another focal plane broadband detector provided in an embodiment of this disclosure. Figure 3 This is a partially magnified schematic diagram of the detector pixel in another focal plane broadband detector provided in this embodiment of the present disclosure. Figure 1 Based on, refer to Figure 2 and Figure 3 In the focal plane broadband detector 10, at least some individual detector pixels 10P include at least two photodiodes 10D connected in parallel, and the corresponding individual detector pixels 10P include at least two photosensitive material layers 14 with different response bands coupled in a planar manner.

[0059] The number of photodiodes 10D connected in parallel within a single detector pixel 10P can be two (see reference). Figure 2 The number of detector pixels 10P, including at least two photodiodes 10D connected in parallel, can be a portion of the detector pixels 10P in the focal plane broadband detector 10, or all of the detector pixels 10P in the focal plane broadband detector 10, without limitation.

[0060] In some embodiments, continue to refer to Figure 1 and Figure 3 The grid common ground electrode 12 also includes a plurality of first strip electrodes 12X arranged along the first direction X and a plurality of second strip electrodes 12Y arranged along the second direction Y. The first strip electrodes 12X and the second strip electrodes 12Y intersect (e.g., perpendicularly) to define a grid 120. The branch electrodes 122 of the grid common ground electrode 12 include a first branch electrode 1221 and a second branch electrode 1222 arranged opposite to each other. The first branch electrode 1221 and the second branch electrode 1222 are respectively connected to two adjacent first strip electrodes 12X.

[0061] In this case, taking two adjacent first strip electrodes 12X as an example, one located above and the other below, the first branch electrode 1221 and the second branch electrode 1222 are respectively connected to one of the first strip electrodes 12X located above and the other below.

[0062] Combination Figure 2 The first branch electrode 1221 and the center electrode 13 correspond to the two electrodes of one of the photodiodes 10D, and the second branch electrode 1222 and the center electrode 13 correspond to the two electrodes of the other photodiode 10D, thus forming two photodiodes 10D connected in parallel. The center electrode 13 can also be called the center common electrode or pixel electrode.

[0063] In some embodiments, continue to refer to Figure 1 or Figure 3 The first branch electrode 1221 and the second branch electrode 1222 are parallel to the second direction Y and are both parallel to the center electrode 13.

[0064] This design simplifies the design and layout of the electrode structure and reduces the overall difficulty in device design and fabrication.

[0065] In some embodiments, continue to refer to Figure 1 or Figure 3 The first branch electrode 1221 and the second branch electrode 1222 are located on the same side of the central electrode 13 along the first direction X, and are opposite to a portion of the central electrode 13.

[0066] by Figure 1 or Figure 3 Taking the orientation shown as an example, the first branch electrode 1221 and the second branch electrode 1222 are both located to the right of the center electrode 13. The first branch electrode 1221 is positioned opposite to the upper part of the center electrode 13, and the second branch electrode 1222 is positioned opposite to the lower part of the center electrode 13. Thus, they respectively constitute photodiodes, and the photodiodes are connected in parallel.

[0067] In some embodiments, continue to refer to Figure 3 Each detection pixel 10P includes a first partition QZ1 and a second partition QZ2, and the central electrode 13 extends into the first partition QZ1 and the second partition QZ2; the photosensitive material layer 14 with different response bands includes a first photosensitive material layer 141 and a second photosensitive material layer 142, the first photosensitive material layer 141 is filled in the first partition QZ1, and the second photosensitive material layer 142 is filled in the second partition QZ2.

[0068] The first photosensitive material layer 141 and the second photosensitive material layer 142 have different response bands, and together with the electrode structure, they form two photodiodes with different detection bands.

[0069] In some embodiments, Figure 4 For along Figure 3 Schematic diagram of the cross-sectional structure between A1 and A2. Figure 5 For along Figure 3 A schematic diagram of the cross-sectional structure between sections B1 and B2. Figure 3 Based on, refer to Figure 4 or Figure 5 The photosensitive material layer 14 (including the first photosensitive material layer 141 or the second photosensitive material layer 142) includes an intrinsic quantum dot layer 14i; the central electrode 13 and the grid common ground electrode 12 are respectively one of an N-type material electrode and a P-type material electrode and the two are different; for example, the central electrode 13 is an N-type material electrode and the grid common ground electrode 12 is a P-type material electrode. In other implementations, the central electrode 13 may also be a P-type material electrode and the corresponding grid common ground electrode 12 may be an N-type material electrode, which is not limited here.

[0070] The intrinsic quantum dot layer 14i is at least filled between the N-type material electrode and the P-type material electrode, and covers the side of the N-type material electrode and the P-type material electrode that is away from the readout circuit substrate 11.

[0071] In this embodiment, the positions of the N-type material electrode and the P-type material electrode determine the effective volume of the photodetector structure. Therefore, the effective volume of the photodetector structure is less affected by the uniformity of the film thickness. Using the horizontal structure device provided in this embodiment is beneficial to improving the uniformity of the device response.

[0072] In some embodiments, continue to refer to Figure 4 or Figure 5The focal plane broadband detector 10 further includes: an N-type quantum dot layer 14N and / or a P-type quantum dot layer 14P; the N-type quantum dot layer 14N is located on the side of the N-type material electrode away from the readout circuit substrate 11, and is located between the readout circuit substrate 11 and the intrinsic quantum dot layer 14i; the P-type quantum dot layer 14P is located on the side of the P-type material electrode away from the readout circuit substrate 11, and is located between the readout circuit substrate 11 and the intrinsic quantum dot layer 14i.

[0073] In this embodiment, the intrinsic quantum dot layer 14i, the N-type quantum dot layer 14N, and the P-type quantum dot layer 14P together constitute a planar PV structure photoelectric detection structure based on colloidal quantum dots. The wavelength range of the quantum dot response can be adjusted by changing parameters such as reaction temperature, reaction time, and reactant ratio during quantum dot synthesis. In this embodiment, the wavelength range of the quantum dot response can be infrared, visible light, ultraviolet, etc. The infrared band specifically includes at least two of the near-infrared, short-wave, mid-wave, and long-wave infrared bands. The quantum dot materials responsive to the infrared band can include, but are not limited to, the following: lead sulfide (PbS), lead selenide (PbSe), mercury telluride (HgTe) quantum dots, and mercury cadmium telluride (HgCdTe) quantum dots; the quantum dots responsive to the visible light band can include perovskite and cadmium telluride (CdTe) quantum dots; and the quantum dots responsive to the ultraviolet band can include perovskite quantum dots.

[0074] The colloidal quantum dots of the intrinsic quantum dot layer 14i may include one or more of the following: lead sulfide (PbS), lead selenide (PbSe), mercuric telluride (HgTe), mercuric selenide (HgSe), perovskite, cadmium telluride (CdTe), and mercuric cadmium telluride (HgCdTe); the preparation and processing methods may include inkjet printing, electrohydrodynamic printing, and nanoimprinting; the thickness of the intrinsic quantum dot layer 14i may be 300 nanometers to 400 nanometers.

[0075] The N-type quantum dot layer 14N may include one or more of bismuth selenide (Bi2Se3), bismuth sulfide (Bi2S3), bismuth telluride (Bi2Te3), zinc oxide (ZnO), cadmium selenide (CdSe), and N-type quantum dots that are the same as those in the intrinsic quantum dot layer. Its preparation and processing methods may include inkjet printing, electrohydrodynamic printing, and nanoimprinting. The thickness of the N-type quantum dot layer 14N may be 40 nanometers to 60 nanometers, for example, 50 nanometers.

[0076] The P-type quantum dot layer 14P may include one or more of silver telluride (Ag2Te), poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS), and P-type quantum dots identical to the intrinsic quantum dot layer. Its preparation and processing methods may include inkjet printing, electrohydrodynamic printing, and nanoimprinting. The thickness of the P-type quantum dot layer 14P may be 40 nanometers to 60 nanometers, for example, 50 nanometers.

[0077] In some embodiments, the material of the electrode structure (including the central electrode and the grid common ground electrode) may include one or more of nickel, chromium, titanium, gold, platinum, silver, aluminum, and zinc. The thickness of the electrode structure may be 20 nanometers to 40 nanometers, and its fabrication method may be micro-nano fabrication methods such as photolithography and etching, which are not limited herein.

[0078] In some embodiments, the focal plane broadband detector 10 further includes: an electron transport layer 14e and / or a hole transport layer 14h; the electron transport layer 14e is located between an N-type material electrode and an N-type quantum dot layer 14N; and the hole transport layer 14h is located between a P-type material electrode and a P-type quantum dot layer 14P.

[0079] This configuration increases the carrier transport rate and improves the device response speed.

[0080] In some embodiments, in the focal plane broadband detector 10, the thickness of the intrinsic quantum dot layer 14i is 300 nm to 400 nm; the thickness of the N-type material electrode is 20 nm to 40 nm; the thickness of the P-type material electrode is 20 nm to 40 nm; the thickness of the N-type quantum dot layer 14N is 40 nm to 60 nm; and the thickness of the P-type quantum dot layer 14P is 40 nm to 60 nm. The intrinsic quantum dot layer 14i fills within the detection pixel 10P and covers the other films therein.

[0081] In this embodiment, the photodiode is a photovoltaic detector. By different doping methods on the quantum dots to control the polarity of the quantum dot layers, an N-type quantum dot layer, an intrinsic quantum dot layer, and a P-type quantum dot layer are brought into contact to form a PIN junction. The different materials have different Fermi levels and different carrier concentrations, generating a contact potential difference that causes the flow of electrons and holes. This carrier movement forms a space charge region, generating a built-in electric field. In a detection scenario, light shines on the PIN junction, generating photogenerated carriers (i.e., electron-hole pairs). These pairs are separated under the influence of the built-in electric field. Holes diffuse to the P-type material electrode, and electrons diffuse to the N-type material electrode, generating a photocurrent.

[0082] refer to Figure 2 In pixel cells based on CMOS readout circuits, detector coupling is achieved through direct injection. During detector exposure, the gate voltage is adjusted to control the conduction of the MOS transistor, and the photocurrent is injected into the MOS transistor and stored in the integrating capacitor. Simultaneously, the injected MOS transistor is turned off under timing control, ending the detector exposure charge accumulation.

[0083] For example, the timing generation circuit uses an external input clock and bias voltage to generate the timing pulse voltage required for the readout circuit to operate, controlling the column-to-row decoding gating of the substrate. The bias generation circuit generates the bias voltage that controls the on / off state of the MOSFETs. After the pixel array exposure integration of the CMOS device is complete, the detector photocurrent is converted into a photovoltage signal. The column-level data acquisition and protection circuit buffers and transmits the voltage signal generated by the selected pixel to the column-level data acquisition and protection circuit. The column-level buffer amplifier, controlled by the bias voltage generated internally by the chip, amplifies the readout signal. Then, four multiplexers operate simultaneously, transmitting the selected signal to four output taps to achieve signal amplification and output, which is then acquired and processed by the test system.

[0084] In this embodiment, the center electrode controls the charging and discharging of the capacitor and the accumulation of charge by controlling the timing and bias voltage, thereby enabling the reading of signals from specific detection pixels. The grid common ground electrode is connected to the ground electrode outside the pixel area.

[0085] In some embodiments, Figure 6 This diagram illustrates an imaging application of the focal plane broadband detector provided in this embodiment of the present disclosure, showing an example of an imaging application of the planar PV structure focal plane broadband detector provided in this application embodiment. By configuring two diodes in the detector pixel as short-wave infrared and mid-wave infrared devices connected in parallel, short-wave light imaging can be performed during the day when there is light, and mid-wave thermal imaging can be performed at night when there is no light. The switching between different wavelengths of imaging during the day and night does not require manual switching; instead, it is automatically selected based on the quantum dot film layer. Specifically, the material's short-wave response is excited when there is light, and there is no short-wave response when there is no light. The mid-wave film layer detects heat and responds, thereby achieving imaging detection during the day and night respectively.

[0086] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0087] The above description is merely a specific embodiment of this disclosure, enabling those skilled in the art to understand or implement it. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this disclosure. Therefore, this disclosure is not to be limited to the embodiments described herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A focal plane broadband detector, characterized in that, include: The pixel region and the peripheral region located on at least one side of the pixel region, wherein the pixel region is provided with an array of detector pixels; The focal plane broadband detector also includes: Read out the circuit substrate, including the common ground electrode located in the peripheral region; A grid common ground electrode is located on one side of the readout circuit substrate and connected to the common ground electrode; the grid common ground electrode includes an array of grids in the pixel area, each grid corresponding to a probe pixel, and a branch electrode extending from each grid; The center electrode is located on the same side of the readout circuit substrate as the grid common ground electrode and is correspondingly disposed within the grid of the detection pixel. It is electrically connected to the readout circuit substrate. The center electrode is electrically insulated from the grid common ground electrode. The center electrode and the branch electrode are at least partially opposite each other. A photosensitive material layer is filled at least between the central electrode and the branch electrode.

2. The focal plane broadband detector according to claim 1, characterized in that, At least some of the individual detection pixels include at least two photodiodes connected in parallel, and each individual detection pixel includes at least two photosensitive material layers with different response bands coupled in a planar manner.

3. The focal plane broadband detector according to claim 1, characterized in that, The grid common ground electrode further includes a plurality of first strip electrodes arranged along a first direction and a plurality of second strip electrodes arranged along a second direction, wherein the first strip electrodes and the second strip electrodes intersect to define the grid; The branch electrodes of the grid common ground electrode include a first branch electrode and a second branch electrode arranged opposite to each other, and the first branch electrode and the second branch electrode are respectively connected to two adjacent first strip electrodes.

4. The focal plane broadband detector according to claim 3, characterized in that, The first branch electrode and the second branch electrode are parallel to each other along the second direction and are both parallel to the center electrode.

5. The focal plane broadband detector according to claim 3, characterized in that, The first branch electrode and the second branch electrode are located on the same side of the central electrode along the first direction and are opposite to a portion of the central electrode.

6. The focal plane broadband detector according to any one of claims 1-5, characterized in that, Each of the detection pixels includes a first partition and a second partition, and the central electrode extends into the first partition and the second partition; The photosensitive material layers with different response bands include a first photosensitive material layer and a second photosensitive material layer. The first photosensitive material layer fills the first partition, and the second photosensitive material layer fills the second partition.

7. The focal plane broadband detector according to any one of claims 1-5, characterized in that, The photosensitive material layer includes an intrinsic quantum dot layer; The central electrode and the grid common ground electrode are respectively one of an N-type material electrode and a P-type material electrode, and the two are different; The intrinsic quantum dot layer is at least filled between the N-type material electrode and the P-type material electrode, and covers the side of the N-type material electrode and the P-type material electrode opposite to the readout circuit substrate.

8. The focal plane broadband detector according to claim 7, characterized in that, Also includes: The N-type quantum dot layer is located on the side of the N-type material electrode facing away from the readout circuit substrate, and is located between the readout circuit substrate and the intrinsic quantum dot layer; And / or, The P-type quantum dot layer is located on the side of the P-type material electrode away from the readout circuit substrate, and is located between the readout circuit substrate and the intrinsic quantum dot layer.

9. The focal plane broadband detector according to claim 8, characterized in that, Also includes: An electron transport layer is located between the N-type material electrode and the N-type quantum dot layer; And / or, A hole transport layer is located between the P-type material electrode and the P-type quantum dot layer.

10. The focal plane broadband detector according to claim 8, characterized in that, The thickness of the intrinsic quantum dot layer is 300 nanometers to 400 nanometers; The thickness of the N-type material electrode is 20 nanometers to 40 nanometers; The thickness of the P-type material electrode is 20 nanometers to 40 nanometers; The thickness of the N-type quantum dot layer is 40 nanometers to 60 nanometers; The thickness of the P-type quantum dot layer is 40 nanometers to 60 nanometers.

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