Infrared device and preparation method

Abstract

The present disclosure relates to an infrared device and a preparation method, the infrared device comprising: a substrate; a detection unit, arranged on one side of the substrate; the detection unit comprises a vertically coupled quantum dot detection structure and a grating array structure, the grating array structure comprises grating units arranged in an array, and a preset number of adjacent grating units form a grating group; the grating lines of each grating unit in the same grating group extend in different directions; the grating units with different grating line extension directions are used to transmit infrared light with different polarization directions, and the quantum dot detection structure is used to generate corresponding electrical signals in response to infrared light with different polarization directions. In this way, by using grating units with different grating line extension directions to transmit infrared light with different polarization directions, multiple infrared images with different polarization directions can be collected in real time, the polarization characteristics of the infrared image are increased, and image interference is reduced, thereby improving the real-time and accuracy of infrared image acquisition, and facilitating real-time and accurate detection of dynamic scenes.

Description

Technical Field

[0001] The present disclosure relates to the field of infrared detection technology, and in particular to an infrared device and a preparation method thereof. Background Art

[0002] At present, infrared detection technology has attracted much attention due to its excellent performance such as long detection distance, high detection sensitivity and ability to work at night, and is usually used in combination with other technologies to expand its uses. For example, since different objects or the same object will produce different polarization states, by combining polarization technology with infrared detection technology, it is possible to easily identify the target object in a complex background.

[0003] However, existing polarization infrared imaging technologies, such as time-sharing polarization imaging, amplitude-sharing polarization imaging, and aperture-sharing polarization imaging, are similar to spectral imaging and usually require the time-sharing acquisition of multiple sets of images to describe the polarization state of the entire scene, which may mask the true polarization characteristics of the entire scene and even produce image interference such as artifacts caused by platform or scene movement, making it impossible to detect dynamic scenes in real time and accurately. Summary of the invention

[0004] In order to solve the above technical problems or at least partially solve the above technical problems, the present disclosure provides an infrared device and a preparation method thereof.

[0005] The present disclosure provides an infrared device, comprising:

[0006] substrate;

[0007] A detection unit is arranged on one side of the substrate;

[0008] The detection unit includes a vertically coupled quantum dot detection structure and a grating array structure, wherein the grating array structure includes grating units arranged in an array, and a preset number of adjacent grating units form a grating group; the grating lines of each grating unit in the same grating group extend in different directions;

[0009] The grating units with different grating line extension directions are used to transmit infrared light with different polarization directions, and the quantum dot detection structure is used to generate corresponding electrical signals in response to infrared light with different polarization directions.

[0010] Optionally, the quantum dot detection structure comprises:

[0011] A first electrode is disposed on one side of the substrate;

[0012] An infrared photosensitive layer is disposed on a side of the first electrode facing away from the substrate;

[0013] A second electrode is disposed on a side of the infrared sensitive layer away from the first electrode;

[0014] Wherein, the grating array structure is arranged between the second electrode and the infrared photosensitive layer.

[0015] Optionally, the quantum dot detection structure comprises:

[0016] A first electrode is disposed on one side of the substrate;

[0017] An infrared photosensitive layer is disposed on a side of the first electrode away from the substrate;

[0018] A second electrode is disposed on a side of the infrared sensitive layer away from the first electrode;

[0019] Wherein, the second electrode is multiplexed into the grating array structure; and each of the grating units is electrically connected.

[0020] Optionally, the period of the grating unit is 0.6um to 1.0um, and the duty cycle is 0.4 to 0.6.

[0021] Optionally, the extending directions of the grating lines of the grating units of the same grating group are sequentially spaced at the same angle.

[0022] Optionally, the grating group further includes a hollow area; the hollow area is used to transmit the non-polarized infrared light.

[0023] Optionally, the hollow area is located in a central area of ​​the grating group.

[0024] Optionally, the grating lines of the grating unit include metal material.

[0025] Optionally, the substrate includes a signal readout circuit; the signal readout circuit includes pixel areas arranged in an array;

[0026] The vertical projection of the grating unit on the substrate corresponds to the pixel area one by one.

[0027] The present disclosure also provides a method for preparing an infrared device, the method comprising:

[0028] providing a substrate;

[0029] forming a detection unit on one side of the substrate;

[0030] Among them, the detection unit includes a vertically coupled quantum dot detection structure and a grating array structure, the grating array structure includes grating units arranged in an array, and a preset number of adjacent grating units form a grating group; the grating lines of each grating unit in the same grating group have different extension directions; the grating units with different grating line extension directions are used to transmit infrared light with different polarization directions, and the quantum dot detection structure is used to generate corresponding electrical signals in response to infrared light with different polarization directions.

[0031] Compared with the prior art, the technical solution provided by the embodiments of the present disclosure has the following advantages:

[0032] The infrared device provided by the embodiment of the present disclosure includes: a substrate; a detection unit, which is arranged on one side of the substrate; the detection unit includes a vertically coupled quantum dot detection structure and a grating array structure, the grating array structure includes grating units arranged in an array, and a preset number of adjacent grating units form a grating group; the grating lines of each grating unit in the same grating group have different extension directions; the grating units with different grating line extension directions are used to transmit infrared light with different polarization directions, and the quantum dot detection structure is used to respond to infrared light with different polarization directions to generate corresponding electrical signals. In this way, by using grating units with different grating line extension directions to transmit infrared light with different polarization directions, multiple infrared images with different polarization directions can be collected in real time, the polarization characteristics of the infrared image are increased, and image interference is reduced, thereby improving the real-time and accuracy of infrared image acquisition, which is conducive to real-time and accurate detection of dynamic scenes. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present disclosure and, together with the description, serve to explain the principles of the present disclosure.

[0034] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0035] Figure 1 A schematic diagram of the structure of an infrared device provided in an embodiment of the present disclosure;

[0036] Figure 2 A schematic diagram of the structure of another infrared device provided in an embodiment of the present disclosure;

[0037] Figure 3 A schematic diagram of the structure of another infrared device provided in an embodiment of the present disclosure;

[0038] Figure 4A schematic diagram of the structure of another infrared device provided in an embodiment of the present disclosure;

[0039] Figure 5 A schematic diagram of the working principle structure of a photovoltaic infrared device provided in an embodiment of the present disclosure;

[0040] Figure 6 A schematic diagram of the structure of another infrared device provided in an embodiment of the present disclosure;

[0041] Figure 7 A schematic diagram of an arrangement structure of a grating unit provided in an embodiment of the present disclosure;

[0042] Figure 8 A schematic diagram of another arrangement structure of grating units provided in an embodiment of the present disclosure;

[0043] Fig. 9 A schematic flow chart of a method for preparing an infrared device provided in an embodiment of the present disclosure.

[0044] Among them, 01, electron transport layer; 02, N-type doping layer; 03, intrinsic quantum dot layer; 04, P-type doping layer; 05, hole transport layer; 110, substrate; 120, detection unit; 121, quantum dot detection structure; 122, grating array structure; 1221, grating unit; 1211, first electrode; 1212, infrared sensitive layer; 1213, second electrode; 41, external power supply; 42, data acquisition module; 43, data analysis and imaging system. DETAILED DESCRIPTION

[0045] In order to more clearly understand the above-mentioned objectives, features and advantages of the present disclosure, the scheme of the present disclosure will be further described below. It should be noted that the embodiments of the present disclosure and the features in the embodiments can be combined with each other without conflict.

[0046] In the following description, many specific details are set forth to facilitate a full understanding of the present disclosure, but the present disclosure may also be implemented in other ways different from those described herein; it is obvious that the embodiments in the specification are only part of the embodiments of the present disclosure, rather than all of the embodiments.

[0047] First, in combination with the relevant background, the defects of the prior art and the improvements of the present application are explained.

[0048] Traditional infrared detection technology has been limited in its development due to the influence of the preparation process. For example, in traditional infrared detection technology, flip-chip bonding technology is usually used to interconnect infrared devices with silicon-based readout integrated circuits (ROIC), which leads to the complexity of the preparation process and a significant increase in cost. In order to break through these bottlenecks, monolithic integration of colloidal quantum dots and silicon-based readout circuits has become a feasible solution. With the development of nano-semiconductor materials, colloidal quantum dots have gradually been applied to infrared devices, promoting the development of infrared detection technology.

[0049] At present, infrared detection technology has attracted much attention due to its excellent performance such as long detection distance, high detection sensitivity and ability to work at night, and is usually used in combination with other technologies to expand its uses. For example, inspired by light waves, it can be known that light waves are a kind of electromagnetic waves, and their electric field vectors and magnetic field vectors are usually described by parameters such as electric field intensity, magnetic field intensity, electric displacement intensity and magnetic flux density. Among them, the polarization characteristics of light are defined as the vibration direction of the electric field vector when it propagates in space, and different objects or the same object will produce different polarization states. By combining polarization technology with infrared detection technology, it is possible to easily identify the target object in a complex background.

[0050] However, in the existing polarized infrared imaging technology, an infrared device can only collect infrared images in one polarization direction at a certain moment, and then collect infrared images in other different polarization directions in time-sharing. It is easily affected by the time interval and polarization direction of the time-sharing collection, which obscures the true polarization characteristics of the entire scene. There is even image interference caused by the movement of the platform or scene, resulting in the inability of existing infrared devices to detect dynamic scenes in real time and accurately.

[0051] In addition, if multiple infrared devices are integrated to collect multiple infrared images with different polarization directions at a certain moment, the overall volume will be too large and the hardware application cost will be increased, which is not conducive to the widespread application of infrared devices.

[0052] In response to at least one of the above problems, an embodiment of the present disclosure provides an infrared device, which can capture multiple infrared images with different polarization directions in real time by utilizing grating units with different grating line extension directions to transmit infrared light with different polarization directions, thereby increasing the polarization characteristics of the infrared image and reducing image interference, thereby improving the real-time and accuracy of infrared image acquisition, and facilitating real-time and accurate detection of dynamic scenes.

[0053] The infrared device and the manufacturing method provided by the embodiments of the present disclosure are exemplarily described below with reference to the accompanying drawings.

[0054] Figure 1 This is a schematic diagram of the structure of an infrared device provided by an embodiment of the present disclosure. Figure 1 The infrared device includes: a substrate 110; a detection unit 120, which is arranged on one side of the substrate 110; the detection unit 120 includes a vertically coupled quantum dot detection structure 121 and a grating array structure 122, the grating array structure 122 includes grating units 1221 arranged in an array, and a preset number of adjacent grating units 1221 form a grating group; the grating lines of each grating unit 1221 in the same grating group extend in different directions; the grating units 1221 with different grating line extension directions are used to transmit infrared light with different polarization directions, and the quantum dot detection structure 121 is used to generate corresponding electrical signals in response to infrared light with different polarization directions.

[0055] The substrate 110 is a substrate for carrying the detection unit 120. For example, the substrate 110 may be a silicon-based readout circuit substrate or other types of substrates for detecting imaging, which are not limited herein.

[0056] Among them, on the same side of the substrate 110, the quantum dot detection structure 121 and the grating array structure 122 are stacked in a direction perpendicular to the plane of the substrate 110, so that the quantum dot detection structure 121 and the grating array structure 122 form a vertical coupling, which can reduce the occupied area of ​​the two on the substrate 110 and improve the overall integration. Exemplarily, the grating array structure 122 can be located above the entire quantum dot detection structure 121, or below the relevant structure in the quantum dot detection structure 121, as long as it can ensure that the grating array structure 122 and the quantum dot detection structure 121 can each achieve the corresponding function, which is not limited here.

[0057] The grating groups in the grating array structure 122 are arranged in an array, and the array arrangement of each grating unit 1221 in each grating group is the same or different. Exemplarily, the grating units 1221 in a grating group may be arranged in n rows and n columns, for example: 3 rows and 3 columns, 4 rows and 4 columns, etc., or in one row and n columns, for example: 1 row and 3 columns, 1 row and 5 columns, etc., or in n rows and m columns, where n and m are positive integers of different sizes, for example: 2 rows and 3 columns, 3 rows and 4 columns, etc. In other embodiments, the grating units 1221 may be arranged in other ways known to those skilled in the art, which are not limited here.

[0058] It can be understood that the array arrangement of each grating unit 1221 in each grating group depends on the aspect ratio of the infrared device provided by the embodiment of the present disclosure. The embodiment of the present disclosure can set its arrangement based on the aspect ratio of the infrared device to ensure that each grating unit 1221 in each grating group covers the preset plane (such as the focal plane) of the infrared device to the greatest extent, that is, the relevant plane where the grating array structure 122 is located, thereby improving the space utilization rate, and preventing the infrared device from generating too many blind pixels and bad pixels, thereby improving the success rate of the infrared device in imaging detection.

[0059] The grating unit 1221 includes grating lines that are spaced and parallel to each other, and the extension direction of the grating lines of the grating unit 1221 has a one-to-one correspondence with the polarization direction of the infrared light. Exemplarily, based on a certain reference direction, if the extension direction of the grating lines of a certain grating unit 1221 is parallel to the reference direction, it can transmit infrared light with a polarization direction parallel to the reference direction; if the extension direction of the grating lines of a certain grating unit 1221 is perpendicular to the reference direction, it can transmit infrared light with a polarization direction perpendicular to the reference direction. The specific correspondence between the extension direction of the grating lines and the polarization direction of the infrared light will be described in detail later.

[0060] Specifically, on a reference plane such as a related plane where the grating array structure 122 is located, the grating lines of each grating unit 1221 in the same grating group have different extension directions, that is, the grating lines of each grating unit 1221 in the same grating group have different inclination angles compared to the same reference direction. With this arrangement, grating units with different grating line extension directions can transmit infrared light with different polarization directions, enriching the polarization information of the infrared light, thereby ensuring the real-time and accuracy of infrared image acquisition.

[0061] The quantum dot detection structure 121 is at least used to generate a photoelectric response. Specifically, the quantum dot detection structure 121 absorbs infrared light of different polarization directions emitted from the grating array structure 122, and performs a photoelectric response based on the infrared light, that is, converts infrared light signals of different polarization directions into corresponding electrical signals, so that subsequent related circuits can perform infrared polarization imaging through the electrical signals. The specific principle of infrared polarization imaging is exemplified later.

[0062] The infrared device provided by the embodiment of the present disclosure includes: a substrate 110; a detection unit 120, which is arranged on one side of the substrate 110; the detection unit 120 includes a vertically coupled quantum dot detection structure 121 and a grating array structure 122, the grating array structure 122 includes grating units 1221 arranged in an array, and adjacent preset numbers of grating units 1221 form a grating group; the grating lines of each grating unit 1221 in the same grating group have different extension directions; the grating units 1221 with different grating line extension directions are used to transmit infrared light with different polarization directions, and the quantum dot detection structure 121 is used to generate corresponding electrical signals in response to infrared light with different polarization directions. In this way, by using the grating units 1221 with different grating line extension directions to transmit infrared light with different polarization directions, multiple infrared images with different polarization directions can be collected in real time, the polarization characteristics of the infrared image are increased, and image interference is reduced, thereby improving the real-time and accuracy of infrared image acquisition, and facilitating real-time and accurate detection of dynamic scenes.

[0063] In some embodiments, Figure 2 A schematic diagram of the structure of another infrared device provided in an embodiment of the present disclosure. Figure 1 Based on Figure 2 The quantum dot detection structure 121 includes: a first electrode 1211, which is arranged on one side of the substrate 110; an infrared photosensitive layer 1212, which is arranged on the side of the first electrode 1211 away from the substrate 110; a second electrode 1213, which is arranged on the side of the infrared photosensitive layer 1212 away from the first electrode 1211; wherein the grating array structure 122 is arranged between the second electrode 1213 and the infrared photosensitive layer 1212.

[0064] For example, Figure 2 Taking the orientation and structure shown as an example, above the substrate 110, the first electrode 1211, the infrared photosensitive layer 1212, the grating array structure 122 and the second electrode 1213 are stacked in sequence.

[0065] Figure 3 A schematic diagram of the structure of another infrared device provided in an embodiment of the present disclosure, Figure 2 Based on Figure 3 Above the first electrode 1211, the infrared sensitive layer 1212 may include an electron transport layer 01, an N-type doped layer 02, an intrinsic quantum dot layer 03, a P-type doped layer 04 and a hole transport layer 05 stacked in sequence, so that a photovoltaic infrared device vertically coupled along the direction from the first electrode 1211 to the second electrode 1213 is formed as a whole.

[0066] Figure 4 A schematic diagram of the structure of another infrared device provided in an embodiment of the present disclosure, Figure 2 Based on Figure 4 , above the first electrode 1211 , the infrared sensitive layer 1212 may include an intrinsic quantum dot 03 layer, so that a photoconductive infrared device vertically coupled along the direction from the first electrode 1211 to the second electrode 1213 is formed as a whole.

[0067] The first electrode 1211 is the bottom electrode of the quantum dot detection structure 121, and is used to collect electrons generated by the photoelectric response. For example, the first electrode 1211 can be indium tin oxide (ITO), zinc oxide (ZnO), indium oxide (In 2 O 3 ), one or more of the carbon nanotubes can be prepared by magnetron sputtering, thermal evaporation, etc. In other embodiments, other electrode materials and electrode formation methods known to those skilled in the art can also be used, which are not limited here.

[0068] The second electrode 1213 is the top electrode of the quantum dot detection structure 121, and is used to collect holes generated by the photoelectric response. For example, the second electrode 1213 can be a transparent electrode that is easy for infrared light to pass through, such as indium tin oxide (ITO), zinc oxide (ZnO), indium oxide (In 2 O 3 ), one or more of the carbon nanotubes can be prepared by magnetron sputtering, electron beam evaporation, etc. In other embodiments, other electrode materials and electrode formation methods known to those skilled in the art can also be used, which are not limited here.

[0069] The infrared photosensitive layer 1212 is a film layer for photoelectric response. Specifically, after external infrared light, such as anisotropic infrared light emitted by the object to be observed and ambient light, is transmitted by the top electrode, in the grating array structure 122, grating units 1221 with different grating line extension directions transmit infrared light with different polarization directions to the infrared photosensitive layer 1212, and the infrared photosensitive layer 1212 can generate photogenerated electron-hole pairs, which are received by corresponding electrodes, such as the first electrode 1211 and the second electrode 1213, to detect imaging.

[0070] For example, for photovoltaic infrared devices, since the intrinsic quantum dots are doped with N-type quantum dots and P-type quantum dots, the electrons and holes generated in the infrared photosensitive layer 1212 are diffused unevenly, so that a built-in potential can be formed inside the photovoltaic infrared device. Under the action of the working voltage applied by an external power supply, the built-in potential is further enhanced, and then the electron-hole pairs are dissociated into free electrons and holes under the action of the enhanced built-in potential. The holes are transmitted to the second electrode 1213 through the hole transport layer 05, and the electrons are transmitted to the first electrode 1211 through the electron transport layer 01; for photoconductive infrared devices, photogenerated electron-hole pairs can be separated under the action of the working voltage applied by an external power supply, and the electrons and holes are directly transmitted to the first electrode 1211 and the second electrode 1213, respectively.

[0071] For example, Figure 5 A schematic diagram of the working principle structure of a photovoltaic infrared device provided in an embodiment of the present disclosure, Figure 2 Based on Figure 5 On the basis that the grating array structure 122 is arranged between the second electrode 1213 and the infrared sensitive layer 1212, the top electrode and the bottom electrode of the infrared device are respectively connected to the external power supply 41. The external power supply 41 can further drive the electrical signal (i.e., electrons) generated by the photoelectric response to move to the substrate 110 by applying an operating voltage to the infrared device, thereby forming a directionally moving current, so as to collect and process the electrical signal in the current.

[0072] In some embodiments, Figure 6A schematic diagram of the structure of another infrared device provided in an embodiment of the present disclosure, Figure 1 Based on Figure 6 The quantum dot detection structure includes: a first electrode 1211, which is arranged on one side of a substrate 110; an infrared sensitive layer 1212, which is arranged on the side of the first electrode 1211 away from the substrate 110; a second electrode 1213, which is arranged on the side of the infrared sensitive layer 1212 away from the first electrode 1211; wherein the second electrode 1213 is multiplexed into a grating array structure; and each grating unit 1221 is electrically connected.

[0073] Specifically, the second electrode 1213 multiplexed into a grating array structure selectively transmits external infrared light, including: grating units with different grating line extension directions transmit infrared light with different polarization directions to the infrared photosensitive layer 1212, and the infrared photosensitive layer 1212 generates photogenerated electron-hole pairs, and then the holes are transmitted to the second electrode 1213, and the electrons are transmitted to the first electrode 1211. It is not difficult to understand that when the second electrode 1213 is multiplexed into a grating array structure, the infrared device can be a photoconductive infrared device or a photovoltaic infrared device. The specific structure of the infrared photosensitive layer 1212 can be understood by referring to the corresponding embodiments above, and will not be repeated here.

[0074] Specifically, by reusing the second electrode 1213 as a grating array structure, the number of film layers of the entire infrared device can be reduced, thereby reducing the overall volume of the infrared device and simplifying the film layer preparation process of the infrared device, thereby achieving a miniaturized design of the infrared device, improving preparation efficiency, and saving overall application costs.

[0075] It should be noted that each grating unit in the grating array structure is provided with a metal frame, and each grating unit is connected to each other through the metal frame to form an electrical connection with each other. With such a configuration, when an external power supply applies an operating voltage to the second electrode 1213 multiplexed into the grating array structure, the operating voltages of each grating unit can remain consistent, which is conducive to the normal operation of the infrared device.

[0076] In some embodiments, reference Figure 1 The period of the grating unit 1221 is 0.6um to 1.0um, and the duty cycle is 0.4 to 0.6.

[0077] The period represents the spacing between grating lines (in micrometers, nanometers or sub-nanometers), and the duty cycle represents the area ratio of the grating lines in the grating unit 1221. In particular, in the embodiment of the present disclosure, the grating unit 1221 is a sub-wavelength grating, and its period and duty cycle both meet the sub-wavelength condition.

[0078] Based on this, the design requirements of the grating unit 1221 are described in detail below in combination with the polarization principle of the grating unit 1221 .

[0079] It should be noted that when the period of the grating unit 1221 is smaller than the wavelength of the incident infrared light, it can exhibit polarization characteristics. Specifically, it can be seen that the infrared light includes TE polarized light parallel to the extension direction of the grating lines and TM polarized light perpendicular to the extension direction of the grating lines. Since the boundary conditions of the two are different, the equivalent refractive indexes of the two are also different, which can be expressed as follows: TE polarized light will excite the electrons on the grating lines to generate current, so that the TE polarized light is reflected by the grating unit 1221, while the TM polarized light cannot induce current because the grating lines are isolated by air gaps. At this time, the TM polarized light can be transmitted through the grating unit 1221.

[0080] Combining the TM polarized light and TE polarized light mentioned above, the main parameters for measuring the polarization performance of the grating unit 1221 include transmittance and extinction ratio, where: the transmittance represents the percentage of TM polarized light passing through the grating unit 1221, and the extinction ratio represents the ratio of the transmittance of TM polarized light to the transmittance of TE polarized light. It is not difficult to know that, in theory, the higher the transmittance and extinction ratio, the better the polarization performance of the grating unit 1221.

[0081] Among them, the period and the duty cycle are important parameters that affect the polarization performance of the grating unit 1221, and the two can directly affect the optical response of the grating unit 1221. Specifically, with respect to the duty cycle, under normal circumstances, the higher the duty cycle of the grating unit 1221, the larger the area occupied by the grating lines, and the smaller the interval between the grating lines, so that the interaction between the grating lines is enhanced, so that the response of the grating unit 1221 to infrared light is enhanced, such as: the transmittance of the grating lines to TM polarized light can be increased, and the scattering efficiency of the grating lines to TE polarized light can be increased, and as more and more infrared light interacts with the grating unit 1221, the efficiency of energy conversion is further increased; with respect to the period, a smaller period can produce a higher frequency response, so that the grating unit 1221 can transmit and refract higher frequency infrared light to form a high-resolution infrared device and improve the quality of infrared polarization imaging.

[0082] Therefore, the embodiment of the present disclosure sets the period of the grating unit 1221 to 0.6um-1.0um and the duty cycle to 0.4-0.6, thereby ensuring that the grating unit 1221 has good polarization performance and further improving the quality of infrared polarization imaging.

[0083] In some embodiments, the extending directions of the grating lines of each grating unit in the same grating group are sequentially spaced at the same angle.

[0084] For example, Figure 7 A schematic diagram of the arrangement structure of a grating unit provided in an embodiment of the present disclosure. Figure 1 Based on Figure 7 , Figure 7 A grating group includes four grating units 1221, and the grating lines of each grating unit 1221 extend in directions 45° apart from each other. Figure 7 Taking the orientation in as an example, relative to the reference direction (such as the vertical direction Y), the extension directions of the grating lines of the four grating units 1221 are 0°, 45°, 90° and 135°, respectively, indicating that the grating group can simultaneously transmit infrared light with four different polarization directions, corresponding to: infrared light with polarization directions of 0°, 45°, 90° and 135°, respectively. In this way, infrared images with four polarization characteristics can be collected.

[0085] Specifically, by setting the grating line extension directions of each grating unit 1221 of the same grating group to be spaced at the same angle in sequence, the grating line extension directions of each grating unit 1221 are evenly spaced, and thus uniform polarization information can be collected through each grating unit 1221 of the grating group, which is beneficial to improving the subsequent imaging quality to reflect the real information of the object to be observed.

[0086] It is not difficult to understand that if the extension directions of the grating lines of each grating unit 1221 of the same grating group are spaced at different angles from each other, uneven polarization information will be collected by each grating unit 1221 of the grating group, such as: the polarization information of some angles is collected more densely, and the polarization information of other angles is collected more sparsely, thereby reducing the subsequent imaging quality.

[0087] Exemplarily, the extension directions of the grating lines of each grating unit 1221 of the same grating group may be spaced apart by 10°, 30° or other angles in sequence, as long as the interval angles are the same, which is not limited here.

[0088] In some embodiments, Figure 8 A schematic diagram of another arrangement structure of grating units provided in an embodiment of the present disclosure. Figure 1 Based on Figure 8 The grating group also includes a hollow area 31; the hollow area 31 is used to transmit non-polarized infrared light.

[0089] Preferably, the hollow area 31 is located in the central area of ​​the grating group. Figure 8 A grating group is shown to include a hollow area 31 and eight grating units 1221. The eight grating units 1221 are arranged around the hollow area 31, and the grating lines of each grating unit 1221 are spaced 22.5° apart from each other. Figure 8Taking the orientation in as an example, relative to the reference direction (such as the vertical direction Y), the extension directions of the grating lines of the eight grating units 1221 are 0°, 22.5°, 45°, 67.5°, 90°, 112.5°, 135° and 157.5°, respectively, indicating that the grating group can simultaneously transmit infrared light with eight different polarization directions, corresponding to: infrared light with polarization directions of 0°, 22.5°, 45°, 67.5°, 90°, 112.5°, 135° and 157.5°, respectively. At the same time, the hollow area 31 can directly transmit non-polarized infrared light, that is, infrared light containing all polarization information, so as to realize the simultaneous collection of polarization information and non-polarization information, thereby being able to obtain more comprehensive information about the object to be observed, thereby improving the accuracy of target recognition and classification.

[0090] In addition, by setting the hollow area 31 in the central area of ​​the grating group, the crosstalk of non-polarization information between the grating groups can be avoided when the hollow area 31 is set in the peripheral area of ​​the grating group, which is conducive to accurately identifying the object to be observed. In other embodiments, the hollow area 31 can also be set at other positions in the central area of ​​the grating group, which is not limited here.

[0091] In some embodiments, the grating lines of the grating unit include a metal material.

[0092] Exemplarily, the metal material may include aluminum, gold, silver, chromium or other metal materials. The type of metal material may be selected according to the polarization performance requirements of the grating unit in the embodiment of the present disclosure and is not limited here.

[0093] Different types of metal materials have different effects on the transmittance and extinction ratio of the grating unit. For example, when the grating lines of the grating unit are made of aluminum, the corresponding transmittance and extinction ratio are both high, thereby ensuring that the grating unit has good polarization performance.

[0094] In some embodiments, reference Figure 1 , the substrate 110 includes a signal readout circuit; the signal readout circuit includes pixel areas arranged in an array; the vertical projection of the grating unit 1221 on the substrate 110 corresponds one-to-one to the pixel area.

[0095] The substrate 110 is provided with pixel electrodes arranged in an array, and the pixel electrodes are electrically connected to the first electrode. Specifically, under the action of the working voltage applied by the external power supply, the infrared device transmits the electrical signal in the infrared photosensitive layer to the pixel electrodes at different positions through the first electrode, and then converts the electrical signal into a digital signal and reads it out through the signal readout circuit, and then outputs the digital signal to the external related circuit to detect the imaging.

[0096] Exemplarily, based on the array arrangement of the grating units 1221, the vertical projection of each grating unit 1221 on the substrate 110 is located in the corresponding pixel area, and the vertical projection area of ​​each grating unit 1221 on the substrate 110 is equal, such as: the vertical projection area of ​​each grating unit 1221 on the substrate 110 may be less than or equal to the area of ​​the corresponding pixel area. In this way, on the basis of improving the integration between the grating units 1221, crosstalk between the corresponding infrared lights transmitted by each grating unit 1221 can be avoided, so as to improve the accuracy of the polarization information collected by the infrared device.

[0097] It can be understood that the infrared device provided in the embodiment of the present disclosure is an optoelectronic imaging device integrated with a complementary metal oxide semiconductor (CMOS) image sensor, and the actual size of each grating unit matches the pixel size of the CMOS image sensor, and each grating unit corresponds one-to-one with the pixel size of the intrinsic quantum dot layer, so that the infrared light emitted from each grating unit is collected and processed in different regions, thereby improving the accuracy of infrared image collection.

[0098] In some embodiments, continue to refer to Figure 5 The infrared device also includes a data acquisition module 42 and a data analysis and imaging system 43.

[0099] The data acquisition module 42 is used to acquire the digital signal output by the signal readout circuit, and the data analysis and imaging system 43 is used to analyze the digital signal and perform infrared polarization imaging. Specifically, the data analysis and imaging system 43 can integrate the digital signal acquired by the data acquisition module 42, analyze and process the digital signal, and then perform detection imaging according to the results of the analysis and processing to obtain a polarization imaging image of the object to be observed in the target band. Exemplarily, the target band can be at least one of short-wave infrared, medium-wave infrared, and long-wave infrared, which is not limited here.

[0100] In some embodiments, reference Figure 1 In this infrared device, the quantum dot detection structure can be arranged in an array above the substrate, and each quantum dot detection structure is located in the corresponding pixel area. On this basis, the grating unit and the quantum dot detection structure are vertically coupled one by one. This arrangement can ensure that the infrared light emitted from the grating unit is received by the corresponding quantum dot detection structure. Compared with the same quantum dot detection structure receiving infrared light emitted by multiple grating units, this method can effectively reduce crosstalk when receiving infrared light, thereby improving the accuracy of infrared image acquisition.

[0101] For example, the array-arranged quantum dot detection structure may be formed by photolithography or other preparation methods known to those skilled in the art, which are not limited herein.

[0102] On the basis of the above-mentioned embodiments, the embodiments of the present disclosure further provide a method for preparing an infrared device, which is used to prepare any one of the infrared devices provided in the above-mentioned embodiments.

[0103] In some embodiments, Fig. 9 A schematic diagram of a method for preparing an infrared device according to an embodiment of the present disclosure is provided. Fig. 9 , the method comprising:

[0104] S210, providing a substrate.

[0105] For example, the substrate may be cleaned by washing the substrate with acetone, isopropyl alcohol and deionized water in sequence.

[0106] S220 , forming a detection unit on one side of the substrate.

[0107] The detection unit includes a vertically coupled quantum dot detection structure and a grating array structure, the grating array structure includes grating units arranged in an array, and a preset number of adjacent grating units form a grating group; the grating lines of each grating unit in the same grating group extend in different directions; the grating units with different grating line extension directions are used to transmit infrared light with different polarization directions, and the quantum dot detection structure is used to respond to infrared light with different polarization directions to generate corresponding electrical signals. The specific preparation steps of the detection unit will be described in detail later and will not be repeated here.

[0108] In some embodiments, forming a quantum dot detection structure includes:

[0109] Step 1: forming a first electrode on one side of the substrate.

[0110] Exemplarily, the first electrode may be prepared by magnetron sputtering or electron beam evaporation, and its thickness may be 30 nm to 60 nm. The preparation method and thickness of the first electrode are not limited herein.

[0111] Step 2: forming an infrared photosensitive layer on the side of the first electrode facing away from the substrate.

[0112] For example, taking the infrared photosensitive layer including an electron transport layer, an N-type doped layer, an intrinsic quantum dot layer, a P-type doped layer and a hole transport layer stacked in sequence on a first electrode as an example, the above film layers can be formed by spin coating, spraying, etc. In other embodiments, the infrared photosensitive layer can also be prepared by other methods known to those skilled in the art, which are not limited here.

[0113] Exemplarily, the thickness of the electron transport layer may be 5nm~20nm, the thickness of the N-type doping layer may be 50nm~200nm, the thickness of the P-type doping layer may be 50nm~200nm, and the thickness of the hole transport layer may be 5nm~20nm, which is not limited here.

[0114] For example, the electron transport layer can be made of zinc oxide (ZnO), titanium dioxide (TiO 2 ) or methyl butyrate (PCBM), the preparation material of the N-type doping layer can be ZnO (zinc oxide), bismuth sulfide (Bi 2 S 3 ), or one of the N-type quantum dots that are the same as the intrinsic quantum dots. The preparation material of the intrinsic quantum dot layer can be mercury sulfide (HgS 2 ), mercury selenide (HgSe), indium antimonide (InSb) or lead selenide (PbSe), and the preparation material of the P-type doping layer can be molybdenum trioxide (MoO 3 ), silver telluride (Ag 2 Te), or a P-type quantum dot that is the same as the intrinsic quantum dot, the preparation material of the hole transport layer can be polystyrene sulfonate (PEDOT:PSS), molybdenum oxide (MoOx) or butylphenyl-N,N″-biphenyl (PolyTPD), which are not limited here.

[0115] It should be noted that, during the synthesis process of intrinsic colloidal quantum dots, the embodiments of the present disclosure can accurately control the absorption wavelength and particle size of the intrinsic colloidal quantum dots by precisely controlling the reaction time and reaction temperature. For example, the longer the reaction time and the higher the reaction temperature, the longer the absorption wavelength and the larger the particle size of the intrinsic colloidal quantum dots. There is no limitation on the absorption wavelength and particle size of the intrinsic colloidal quantum dots. It is only necessary to ensure that the absorption wavelength can cover the short-wave infrared, medium-wave infrared and long-wave infrared ranges.

[0116] Step 3: forming a second electrode on a side of the infrared sensitive layer away from the first electrode.

[0117] Exemplarily, the second electrode may be prepared by magnetron sputtering or electron beam evaporation, and its thickness may be 30 nm to 60 nm. The preparation method and thickness of the second electrode are not limited herein.

[0118] The grating array structure is arranged between the second electrode and the infrared photosensitive layer, and the specific preparation steps of the grating array structure are exemplarily described later.

[0119] In some embodiments, forming a grating array structure specifically includes the following steps:

[0120] Step 1: providing a photoresist coating layer of a preset thickness.

[0121] Specifically, a photoresist of a preset thickness may be coated on the upper surface of the hole transport layer to form a photoresist coating layer, so as to prepare a photoresist treatment layer later. Exemplarily, the thickness of the photoresist may be 40 nm, 60 nm, or other thicknesses known to those skilled in the art, which are not limited here.

[0122] Step 2: Pre-bake, expose and develop the photoresist coating layer in sequence to form a photoresist treatment layer with a preset pattern.

[0123] The photoresist coating layer is formed into a photoresist processing layer by photolithography. For example, the photoresist coating layer can be irradiated with ultraviolet light, and the ultraviolet light can be concentrated on the surface of the photoresist coating layer through a mask to form a photoresist processing layer with a preset pattern.

[0124] Exemplarily, the photoresist processing layer may include a groove structure and a protrusion structure to correspond to the pattern required for forming the grating. The specific shape of the pattern may be set according to the grating preparation requirements of the embodiment of the present disclosure and is not limited here.

[0125] Step three: Use electron beam evaporation or sputtering to coat the photoresist treatment layer with a metal film to obtain a sample to be processed.

[0126] Exemplarily, the material of the metal film may be aluminum, copper, silver, chromium, nickel or other metal materials, which are not limited here.

[0127] Step 4: soak and peel off the sample to be processed using an organic solution to obtain a metal grating or grating array structure.

[0128] Illustratively, the organic solution may be acetone. In other embodiments, the organic solution may also be other types of organic solutions known to those skilled in the art, which are not limited herein.

[0129] It should be noted that, in this article, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0130] The above description is only a specific embodiment of the present disclosure, so that those skilled in the art can understand or implement the present disclosure. Various modifications to these embodiments will be 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 the present disclosure. Therefore, the present disclosure will not be limited to the embodiments described herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An infrared device, characterized in that: include: substrate; A detection unit is arranged on one side of the substrate; The detection unit includes a vertically coupled quantum dot detection structure and a grating array structure, wherein the grating array structure includes grating units arranged in an array, and a preset number of adjacent grating units form a grating group; the grating lines of each grating unit in the same grating group extend in different directions; The grating units with different grating line extension directions are used to transmit infrared light with different polarization directions, and the quantum dot detection structure is used to generate corresponding electrical signals in response to infrared light with different polarization directions; The grating group further includes a hollow area; the hollow area is used to transmit the non-polarized infrared light; the hollow area is located in the central area of ​​the grating group; The quantum dot detection structure comprises: A first electrode is disposed on one side of the substrate; An infrared photosensitive layer is disposed on a side of the first electrode facing away from the substrate; A second electrode is disposed on a side of the infrared sensitive layer away from the first electrode; Wherein, the grating array structure is arranged between the second electrode and the infrared photosensitive layer; Alternatively, the quantum dot detection structure comprises: A first electrode is disposed on one side of the substrate; An infrared photosensitive layer is disposed on a side of the first electrode facing away from the substrate; A second electrode is disposed on a side of the infrared sensitive layer away from the first electrode; Wherein, the second electrode is multiplexed into the grating array structure; and each of the grating units is electrically connected.

2. The infrared device according to claim 1, characterized in that: The period of the grating unit is 0.6um-1.0um, and the duty cycle is 0.4-0.

6.

3. The infrared device according to claim 1, characterized in that: The extending directions of the grating lines of the grating units of the same grating group are sequentially spaced at the same angle.

4. The infrared device according to claim 1, characterized in that: The grating lines of the grating unit include metal material.

5. The infrared device according to any one of claims 1 to 4, characterized in that: The substrate includes a signal readout circuit; the signal readout circuit includes pixel areas arranged in an array; The vertical projection of the grating unit on the substrate corresponds to the pixel area one by one.

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