Cmos quantum dot imaging chip, preparation method and driving method thereof

Abstract

Embodiments of the present disclosure relate to a CMOS quantum dot imaging chip, a preparation method and a driving method thereof. The CMOS quantum dot imaging chip comprises a substrate; a detection unit arranged on one side of the substrate and arranged in an array; the detection unit comprises an ultraviolet-visible light detection subunit and an infrared light detection subunit; the vertical projection of the ultraviolet-visible light detection subunit on the substrate is staggered with the vertical projection of the infrared light detection subunit on the substrate; the ultraviolet-visible light detection subunit is used for outputting a corresponding electrical signal in response to incident ultraviolet light and incident visible light; and the infrared light detection subunit is used for outputting a corresponding electrical signal in response to infrared light. Thus, on the basis of the existing visible light detection CMOS imaging chip, the ultraviolet-visible light detection subunit and the infrared light detection subunit are combined into the same chip, the ultraviolet light and infrared light detection wave bands are expanded, and the imaging detection of ultraviolet-visible-infrared wide spectrum based on the same CMOS quantum dot imaging chip is realized.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of photoelectric sensors, in particular to a CMOS quantum dot imaging chip and a preparation method and a driving method thereof. BACKGROUND

[0002] In the prior art, a complementary metal oxide semiconductor (CMOS) imaging chip has the advantages of low cost, low power consumption, high integration and fast response speed, and thus the CMOS image sensor has been widely applied in the fields of machine vision, security monitoring and biological imaging. The existing CMOS image sensor converts the incident visible light signal into an electrical signal by using a silicon photodetector, and integrates the silicon photodetector array as a whole on a silicon-based readout circuit to achieve high performance and low cost imaging.

[0003] However, due to the limitation of the band gap of silicon itself, the detection range of the existing silicon photodetector is only 400nm to 1000nm, i.e. covering the visible light and near-infrared, and it cannot detect the ultraviolet band and other infrared bands. SUMMARY

[0004] In order to solve the above technical problems or at least partially solve the above technical problems, the present disclosure provides a CMOS quantum dot imaging chip and a preparation method and a driving method thereof.

[0005] The present disclosure provides a CMOS quantum dot imaging chip, comprising:

[0006] a substrate;

[0007] a detection unit arranged on one side of the substrate and arranged in an array;

[0008] The detection unit comprises an ultraviolet-visible light detection subunit and an infrared light detection subunit; the vertical projection of the ultraviolet-visible light detection subunit on the substrate is staggered with the vertical projection of the infrared light detection subunit on the substrate; the ultraviolet-visible light detection subunit is used to output corresponding electrical signals in response to incident ultraviolet light and incident visible light; and the infrared light detection subunit is used to output corresponding electrical signals in response to infrared light.

[0009] The present disclosure also provides a preparation method of a CMOS quantum dot imaging chip, which is used to prepare any one of the above-mentioned CMOS quantum dot imaging chips; the method comprises:

[0010] providing a substrate;

[0011] Forming an array of detection units on one side of the substrate; the detection units include ultraviolet-visible light detection sub-units and infrared light detection sub-units; the vertical projection of the ultraviolet-visible light detection sub-units on the substrate is staggered with the vertical projection of the infrared light detection sub-units on the substrate; the ultraviolet-visible light detection sub-units are used to output corresponding electrical signals in response to incident ultraviolet light and incident visible light; and the infrared light detection sub-units are used to output corresponding electrical signals in response to infrared light.

[0012] The present disclosure also provides a driving method of a CMOS quantum dot imaging chip, which is used to drive any one of the CMOS quantum dot imaging chips described above; the method comprises:

[0013] Resetting the circuit by using a timing control circuit and collecting voltage signals generated by photoelectric responses and filtering noise signals based on a set incident light irradiation time;

[0014] Selecting the voltage signals overlapping the row pixel region and the column pixel region by using a readout logic circuit and reading out after amplification;

[0015] Forming detection imaging of visible light, ultraviolet light and infrared light by using a signal processing circuit based on the voltage signals generated by photoelectric responses transmitted by the silicon-based readout circuit substrate.

[0016] Compared with the prior art, the technical solution provided by the embodiments of the present disclosure has the following advantages:

[0017] The CMOS quantum dot imaging chip provided by the embodiments of the present disclosure comprises a substrate; a detection unit is arranged on one side of the substrate and is arrayed; the detection unit comprises ultraviolet-visible light detection sub-units and infrared light detection sub-units; the vertical projection of the ultraviolet-visible light detection sub-units on the substrate is staggered with the vertical projection of the infrared light detection sub-units on the substrate; the ultraviolet-visible light detection sub-units are used to output corresponding electrical signals in response to incident ultraviolet light and incident visible light; and the infrared light detection sub-units are used to output corresponding electrical signals in response to infrared light. Thus, on the basis of the existing detection visible light CMOS imaging chip, the ultraviolet-visible light detection sub-units and the infrared light detection sub-units are combined into the same chip, the ultraviolet light and infrared light detection waveband is expanded, and ultraviolet-visible-infrared wide spectrum imaging detection based on the same CMOS quantum dot imaging chip is realized. BRIEF DESCRIPTION OF DRAWINGS

[0018] The accompanying drawings, which are incorporated into and form part of the specification, illustrate embodiments consistent with the present disclosure and, together with the specification, serve to explain the principles of the present disclosure.

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure or the prior art, the drawings needed to be used in the embodiments or prior art description will be briefly introduced as follows. Obviously, those skilled in the art can obtain other drawings according to these drawings without any creative effort.

[0020] Figure 1 A structural schematic diagram of a CMOS quantum dot imaging chip provided by an embodiment of the present disclosure is shown in the figure.

[0021] Figure 2 A structural schematic diagram of another CMOS quantum dot imaging chip provided by an embodiment of the present disclosure is shown in the figure.

[0022] Figure 3 A structural schematic diagram of a CMOS quantum dot imaging chip with a normal incidence structure provided by an embodiment of the present disclosure is shown in the figure.

[0023] Figure 4 A structural schematic diagram of a CMOS quantum dot imaging chip with a back incidence structure provided by an embodiment of the present disclosure is shown in the figure.

[0024] Figure 5 A schematic diagram of photoluminescence and absorption spectrum of an ultraviolet colloidal quantum dot film provided by an embodiment of the present disclosure is shown in the figure.

[0025] Figure 6 A schematic diagram of distribution of a detection unit provided by an embodiment of the present disclosure is shown in the figure.

[0026] Figure 7 A schematic diagram of distribution of another detection unit provided by an embodiment of the present disclosure is shown in the figure.

[0027] Figure 8 A structural schematic diagram of an infrared light detection subunit provided by an embodiment of the present disclosure is shown in the figure.

[0028] Figure 9 A structural schematic diagram of another infrared light detection subunit provided by an embodiment of the present disclosure is shown in the figure.

[0029] Figure 10 A schematic diagram of comparison of infrared response before and after preparation of an infrared light detection subunit provided by an embodiment of the present disclosure is shown in the figure.

[0030] Figure 11 A schematic diagram of comparison of ultraviolet response before and after preparation of an ultraviolet colloidal quantum dot film provided by an embodiment of the present disclosure is shown in the figure.

[0031] Figure 12 A flowchart of a preparation method of a CMOS quantum dot imaging chip provided by an embodiment of the present disclosure is shown in the figure.

[0032] Figure 13A device schematic diagram for preparing an infrared detector and an ultraviolet colloidal quantum dot film by a spraying method is provided for the embodiments of the present disclosure.

[0033] Figure 14 A process schematic diagram for preparing an infrared detector and an ultraviolet colloidal quantum dot film by a photolithography method is provided for the embodiments of the present disclosure.

[0034] Figure 15 A performance comparison schematic diagram of a light guide type infrared detector and a photovoltaic type infrared detector is provided for the embodiments of the present disclosure.

[0035] Figure 16 A flowchart for forming an infrared light detection subunit is provided for the embodiments of the present disclosure.

[0036] Figure 17 A flowchart for a CMOS quantum dot imaging chip driving method is provided for the embodiments of the present disclosure.

[0037] Figure 18 A visible light detector and an ultraviolet light-visible light detection subunit imaging comparison schematic diagram is provided for the embodiments of the present disclosure.

[0038] Figure 19 An ultraviolet light-visible light-infrared light three-color imaging effect schematic diagram is provided for the embodiments of the present disclosure.

[0039] In the drawings: 110, substrate; 111, metal wiring layer; 120, detection unit; 130, ultraviolet light-visible light detection subunit; 131, visible light detector; 132, ultraviolet colloidal quantum dot film; 133, transparent bottom electrode; 140, infrared light detection subunit; 141, first electrode; 142, infrared sensing layer; 143, second electrode; 01, intrinsic quantum dot layer; 02, hole transport layer; 03, P-type quantum dot layer; 04, N-type quantum dot layer; 05, electron transport layer; 30, heating plate; 31, detector substrate; 32, mask plate; 33, spray gun filled with colloidal quantum dot solution. DETAILED DESCRIPTION

[0040] In order to more clearly understand the above-mentioned purposes, features and advantages of the present disclosure, the solutions 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.

[0041] In the following description, many specific details are set forth in order to provide a thorough understanding of the present disclosure, but the present disclosure can also be implemented in other ways different from those described herein; obviously, the embodiments in the description are only some of the embodiments of the present disclosure, not all the embodiments.

[0042] First, in combination with the relevant background, and for this improvement and the proposed embodiments of the present disclosure are briefly described.

[0043] At present, the existing complementary metal oxide semiconductor (CMOS) is a mainstream semiconductor process, which has the advantages of low power consumption and fast speed. For this, based on the CMOS process design, it is combined with the mature silicon photodetector. By using the silicon photodetector, the incident visible light signal can be converted into an electrical signal. At the same time, the silicon photodetector array is integrated into the silicon-based readout circuit as a whole, which can constitute a CMOS image sensor to realize high performance and low cost imaging. Based on the above working principle, and the CMOS image sensor has the advantages of low cost, low power consumption, fast response speed and high integration, the CMOS image sensor has an important position in the field of optoelectronics, such as in the optical field of smart phones and cameras, unmanned cars, large-scale remote sensing imaging, etc. have a wide range of applications.

[0044] However, limited by the band gap of silicon material itself, the detection range of the silicon photodetector can only reach the visible light band (400nm-700nm) and the near-infrared band (800nm-1100nm), and cannot detect the longer wavelength infrared band (1-15μm), or the shorter wavelength ultraviolet band (10nm-400nm). These two bands have important significance in the field of optics. Among them, the infrared band contains information such as chemical bonds and temperature distribution, and has high atmospheric transmittance, and can be unaffected by the weather, so infrared detection has important applications in environmental monitoring, national security and autonomous driving fields. The ultraviolet band has a higher power density than visible light and infrared bands, and has a wide range of applications in the fields of biological medicine, micro-nano processing and electronic communication. At present, the CMOS focal plane imaging sensor (or CMOS image sensor) based on the silicon photodetector cannot detect the infrared band and the ultraviolet band, which greatly limits the application of CMOS imaging chips.

[0045] At present, the infrared detector uses indium gallium arsenide (InGaAs), indium antimonide (InSb) and mercury cadmium telluride (HgCdTe) bulk materials. Due to the requirement of crystal structure, these materials need high-quality single crystal substrate. At the same time, it is difficult to integrate the photodetector of these bulk materials with CMOS silicon-based readout circuit, so the preparation process of molecular beam epitaxy and flip-chip bonding is required. Therefore, the preparation cost of infrared detector is increased, and the infrared detector is limited to military and industrial fields. For the detection of ultraviolet band, the problems faced are the same as those of infrared bulk materials. The existing ultraviolet photosensitive materials, such as gallium nitride (GaN), silicon carbide (SiC) and zinc oxide (ZnO), are all bulk materials, which are incompatible with silicon-based CMOS readout circuit. In view of the above reasons, the existing bulk infrared and ultraviolet materials cannot be combined with visible light silicon-based CMOS image sensor and are not matched with silicon-based readout circuit, making it extremely difficult to integrate infrared, visible light and ultraviolet detectors, and wide-spectrum detection of ultraviolet, visible light and infrared light cannot be realized.

[0046] With the emergence of colloidal quantum dots, the problems faced by existing infrared and ultraviolet bulk materials are solved. Colloidal quantum dots are three-dimensional size-limited semiconductor nanocrystals with very small size (usually less than 10 nanometers). The properties of colloidal quantum dots can be directly controlled by quantum confinement effect. For example, for infrared band, the response band of colloidal quantum dots can be controlled to short-wave infrared, medium-wave infrared, long-wave infrared and terahertz band by controlling the reaction conditions; for ultraviolet band, the absorption wavelength and ultraviolet photoluminescence spectrum of colloidal quantum dots can be changed by changing the composition and proportion of the substances involved in the reaction.

[0047] In addition, colloidal quantum dots can be operated by low-cost and easily scalable colloidal technology. Compared with other photosensitive materials, colloidal quantum dots have the advantages of adjustable optical properties (such as adjustable quantum dot size and absorption band), liquid phase processing and silicon-based compatibility, so that the liquid colloidal quantum dots prepared on the substrate can be prepared into devices. The preparation process is simple, suitable for large-scale production and greatly reduces the material processing cost.

[0048] In summary, the following defects exist in the prior art, which are summarized and described as follows.

[0049] Firstly, the detection range of silicon-based CMOS image sensor can only cover the visible light band of 400-700 nm and the near-infrared band of 800-1100 nm, and cannot detect the infrared band of 1-15 μm and the ultraviolet band of 10-400 nm.

[0050] Secondly, the preparation process of existing infrared bulk materials and ultraviolet bulk materials is complex and the cost is high.

[0051] Thirdly, the existing infrared bulk material and ultraviolet bulk material are incompatible with the silicon-based readout circuit, and it is difficult to combine with the visible light CMOS imaging chip, and it is impossible to realize the ultraviolet-visible-infrared wide spectrum detection imaging.

[0052] Based on this, the colloidal quantum dots are processed to the silicon-based readout circuit by means of spin coating, spraying and photolithography, the quantum dot film can be patterned (prepared into a quantum dot film with a required shape), so that the horizontal coupling of the infrared detector and the visible light detector can be realized, the ultraviolet colloidal quantum dot film is added to the visible light detection circuit, the ultraviolet light is converted into visible light based on the photoluminescence principle, an ultraviolet-enhanced ultraviolet-visible light detection channel is formed, and finally an ultraviolet-visible-infrared CMOS imaging chip is formed, realizing the ultraviolet-visible-infrared wide spectrum detection.

[0053] Therefore, in order to solve at least one of the above problems, the present disclosure provides a CMOS quantum dot imaging chip, a preparation method and a driving method thereof. The CMOS quantum dot imaging chip comprises a substrate; a detection unit arranged on one side of the substrate and arranged in an array; the detection unit comprises an ultraviolet-visible light detection subunit and an infrared light detection subunit; the vertical projection of the ultraviolet-visible light detection subunit on the substrate is staggered with the vertical projection of the infrared light detection subunit on the substrate; the ultraviolet-visible light detection subunit is used for outputting corresponding electrical signals in response to incident ultraviolet light and incident visible light; the infrared light detection subunit is used for outputting corresponding electrical signals in response to infrared light. Thus, on the basis of the existing detection visible light CMOS imaging chip, the ultraviolet-visible light detection subunit and the infrared light detection subunit are combined into the same chip, the ultraviolet light and infrared light detection waveband is expanded, and the ultraviolet-visible-infrared wide spectrum imaging detection is realized.

[0054] The CMOS quantum dot imaging chip, the preparation method and the driving method thereof provided by the embodiments of the present disclosure will be exemplarily described below with reference to the accompanying drawings.

[0055] Exemplarily, in some embodiments, Figure 1 A structural schematic diagram of a CMOS quantum dot imaging chip provided by the embodiments of the present disclosure is shown in FIG. 1. As shown in FIG. 1, the CMOS quantum dot imaging chip comprises a substrate 1, an ultraviolet-visible light detection subunit 2 and an infrared light detection subunit 3. Figure 1The CMOS quantum dot imaging chip comprises a substrate 110; a detection unit 120 arranged on one side of the substrate 110 and arranged in an array; the detection unit 120 comprises an ultraviolet-visible light detection subunit 130 and an infrared light detection subunit 140; the vertical projection of the ultraviolet-visible light detection subunit 130 on the substrate 110 is staggered with the vertical projection of the infrared light detection subunit 140 on the substrate 110; the ultraviolet-visible light detection subunit 130 is used for outputting a corresponding electrical signal in response to incident ultraviolet light and incident visible light; and the infrared light detection subunit 140 is used for outputting a corresponding electrical signal in response to infrared light.

[0056] The substrate 110 is a substrate for forming the ultraviolet-visible light detection subunit 130 and the infrared light detection subunit 140. For example, the substrate can be a silicon substrate or other type of substrate for detecting imaging, which is not limited herein.

[0057] The detection unit 120 is arranged above the substrate 110. It is noted that the vertical projection of the detection unit 120 on the substrate 110 is arranged in an array. For example, the detection unit 120 can be arranged in an array of 6 rows and 6 columns, 3 rows and 3 columns, or other number and arrangement.

[0058] The ultraviolet-visible light detection subunit 130 has two application scenarios. Specifically, when visible light is incident, the visible light is directly transmitted and a corresponding electrical signal is output; when ultraviolet light is incident, the incident ultraviolet light is absorbed and converted into visible light, and a corresponding electrical signal is output. The infrared light detection subunit 140 outputs a corresponding electrical signal in response to infrared light. Based on this, the electrical signals output in response can be fused after signal processing, so as to realize imaging detection of ultraviolet light, visible light and infrared light bands.

[0059] On the basis of forming the array of detection units 120, the vertical projection area of each detection unit 120 on the chip is equal, the vertical projection area of the ultraviolet-visible light detection subunit 130 included therein is at least the area formed by one detection unit 120, and the vertical projection area of the infrared light detection subunit 140 included therein is also at least the area formed by one detection unit 120. For example, when the detection units 120 are arranged in an array of 2 rows and 2 columns, a total of 4 detection units 120 with equal areas are formed. The vertical projection area of the infrared light detection subunit 140 can occupy the area of 2 detection units 120, and the vertical projection area of the ultraviolet-visible light detection subunit 130 can also occupy the area of 2 detection units 120. In this way, the vertical projection of the ultraviolet-visible light detection subunit 130 on the substrate 110 is staggered with the vertical projection of the infrared light detection subunit 140 on the substrate 110, which is beneficial for imaging detection.

[0060] The CMOS quantum dot imaging chip provided in this disclosure includes a substrate; a detection unit disposed on one side of the substrate and arranged in an array; the detection unit includes an ultraviolet-visible light detection subunit and an infrared light detection subunit; the vertical projections of the ultraviolet-visible light detection subunit on the substrate and the vertical projections of the infrared light detection subunit on the substrate are staggered; the ultraviolet-visible light detection subunit is used to output corresponding electrical signals in response to incident ultraviolet light and incident visible light; the infrared light detection subunit is used to output corresponding electrical signals in response to infrared light. Thus, based on existing visible light detection CMOS imaging chips, the ultraviolet-visible light detection subunit and the infrared light detection subunit are combined into the same chip, expanding the ultraviolet and infrared light detection bands and realizing broadband imaging detection of ultraviolet-visible-infrared light based on the same CMOS quantum dot imaging chip.

[0061] In some embodiments, Figure 2 This is a schematic diagram of the structure of another CMOS quantum dot imaging chip provided in an embodiment of this disclosure. Figure 1 Based on reference Figure 2 The CMOS quantum dot imaging chip also includes a metal wiring layer 111, and an infrared light detection subunit 140 is connected to the side of the metal wiring layer 111 away from the substrate 110.

[0062] It should be noted that the metal wiring layer 111 may be a structure formed above the substrate 110. For example, referring to... Figure 2 ,by Figure 2 Taking the shown orientation and structure as an example, the metal wiring layer 111 is disposed above the plane of the substrate 110, and the infrared light detection subunit 140 is vertically disposed above the plane of the metal wiring layer 111. This arrangement allows the infrared light detection subunit 140 to be formed on the chip surface, that is, signal coupling can be directly performed on the silicon-based readout circuit, breaking through the limitations of existing visible light CMOS imaging chips.

[0063] In some embodiments, Figure 3 This is a schematic diagram of a CMOS quantum dot imaging chip with a normal incidence structure provided in an embodiment of this disclosure. Figure 4 This is a schematic diagram of a back-incidence CMOS quantum dot imaging chip structure provided in an embodiment of this disclosure. Referring to the foregoing, see below... Figure 3 , Figure 3 The chip has a forward-incident structure. The ultraviolet-visible light detection subunit 130 includes a visible light detector 131, which is disposed on the side of the substrate 110 facing the metal wiring layer 111, or on the side of the metal wiring layer 111 away from the substrate 110, as shown in the reference. Figure 4 , Figure 4The middle chip is a back incidence structure, which is used for receiving visible light and converting into corresponding electrical signals; the ultraviolet colloidal quantum dot film 132 is arranged on the light incidence side of the visible light detector 131, which is used for absorbing the incident ultraviolet light and generating visible light through photoluminescence or transmitting the incident visible light; the transparent bottom electrode 133 is arranged on the side of the ultraviolet colloidal quantum dot film 132 facing the visible light detector 131; the visible light detector 131 and the ultraviolet colloidal quantum dot film 132 are arranged one by one.

[0064] Exemplarily, the transparent bottom electrode 133 can be one of indium tin oxide (ITO) and fluorine-doped tin dioxide (FTO), and can also be an electrode of other materials, which is not limited here.

[0065] Exemplarily, the colloidal quantum dots used in the preparation of the ultraviolet colloidal quantum dot film 132 can be one or more of perovskite, zinc selenide (ZnSe), zinc sulfide (ZnSe), zinc oxide (ZnO), cadmium selenide (CdSe), cadmium telluride (CdTe), cadmium sulfide (CdS) and cadmium zinc sulfide (CdZnS), which is not limited here. It should be noted that the ultraviolet colloidal quantum dot material (colloidal quantum dots used in the preparation of the ultraviolet colloidal quantum dot film) is used as a photoelectric sensitive material, by adjusting the types and proportions of the reaction substances in the colloidal quantum dots, the photoluminescence and absorption spectrum of the ultraviolet colloidal quantum dots can be controlled, the color of the ultraviolet colloidal quantum dot film and the color of the visible light radiated (photoluminescence) after being irradiated by ultraviolet light can be adjusted according to the actual application requirements. In addition, the ultraviolet colloidal quantum dot film is prepared on the corresponding chip surface above the visible light detector 131, the ultraviolet colloidal quantum dot film can further convert the absorbed ultraviolet light into visible light, which is received and detected by the visible light detector 131, and the device formed has high sensitivity and good performance.

[0066] Among them, the visible light detector 131 is a detector for converting visible light signals into electrical signals; exemplarily, the visible light detector 131 can be a silicon photodetector, which is prepared and integrated into a silicon-based readout circuit in a flow sheet process. And the silicon photodetector and the ultraviolet colloidal quantum dot film 132 correspond one by one, and the combination of the two can realize high-performance and low-cost imaging detection based on ultraviolet light and visible light.

[0067] It should be noted that according to the actual application scene of the chip, the CMOS quantum dot imaging chip can have two structures of normal incidence and back incidence. It is not difficult to understand that when the CMOS quantum dot imaging chip adopts the structure of normal incidence, the CMOS quantum dot imaging chip is placed in the front relative to the incident light, and the incident light needs to pass through the metal wiring layer 111 to enter the visible light detector 131; when the CMOS quantum dot imaging chip adopts the structure of back incidence, the CMOS quantum dot imaging chip is placed in the back relative to the incident light, and the incident light can enter the visible light detector 131 without passing through the metal wiring layer 111.

[0068] In combination with the foregoing, reference is made to Figure 3 and Figure 4 . Specifically, according to the placement direction of the chip relative to the incident light, the position of the visible light detector 131 in the chip can have two kinds, in the first mode (normal incidence), the visible light detector 131 is located on the side of the substrate 110 facing the metal wiring layer 111, that is, according to the direction of the incident light from top to bottom, the visible light detector 131 can be arranged inside the silicon wafer below the metal wiring layer 111; in the second mode (back incidence), the visible light detector 131 is located on the side of the metal wiring layer 111 away from the substrate 110, that is, according to the direction of the incident light from top to bottom, the visible light detector 131 is arranged inside the uppermost silicon wafer, located above the metal wiring layer 111. Among them, the functions of the two structures are consistent, and any one of the normal incidence and back incidence modes can be selected according to the actual needs of the subsequent circuit and electrode. Since the incident light does not need to pass through the metal wiring layer 111, the sensitivity of the back incidence structure is higher.

[0069] Among them, taking the structure and orientation shown in Figure 3 and Figure 4 as an example, the ultraviolet colloidal quantum dot film is formed on the surface of the chip, that is, it can be directly coupled on the silicon-based readout circuit, breaking through the limitation that the existing ultraviolet bulk material cannot be combined with the visible light CMOS imaging chip. It should be noted that the visible light detector 131 and the ultraviolet colloidal quantum dot film 132 are arranged one by one, when the incident light is ultraviolet light, the ultraviolet colloidal quantum dot film 132 absorbs the incident ultraviolet light and generates visible light through photoluminescence, the generated visible light is received by the visible light detector 131 located below the ultraviolet colloidal quantum dot film 132, and a corresponding electrical signal is generated in response. When the incident light is visible light, the ultraviolet colloidal quantum dot film 132 transmits the incident visible light, and is received by the visible light detector 131 located below the ultraviolet colloidal quantum dot film 132, and a corresponding electrical signal is generated in response.

[0070] In some embodiments, the ultraviolet colloidal quantum dot film 132 is used to transmit a first waveband and photoluminescence for a second waveband; the first waveband belongs to the visible light waveband, and the second waveband belongs to the ultraviolet light waveband.

[0071] When the incident light is ultraviolet light, the ultraviolet colloidal quantum dot film 132 absorbs the incident ultraviolet light, i.e., corresponds to the second waveband, and converts the light of the ultraviolet light waveband, i.e., the second waveband, into visible light in the ultraviolet colloidal quantum dot film 132 based on the principle of ultraviolet light photoluminescence; when the incident light is visible light, the ultraviolet colloidal quantum dot film 132 transmits the visible light, i.e., corresponds to the first waveband.

[0072] According to the principle, when visible light is incident, the light passes through the ultraviolet colloidal quantum dot film 132, is received by the visible light detector 131, and is converted into an electrical signal and read out; when an ultraviolet light source is incident, the ultraviolet colloidal quantum dot film 132 radiates visible light based on the principle of photoluminescence, and then the visible light detector 131 detects and reads out the signal.

[0073] Exemplarily, when preparing the ultraviolet colloidal quantum dot film 132 (which can also be referred to as an ultraviolet photosensitive layer), a spraying method and a photolithography method can be used for preparation. Specifically, when the ultraviolet colloidal quantum dot film 132 is prepared by using the spraying method, first, a transparent bottom electrode is prepared by using a thermal evaporation method, and the thickness thereof can be 50 nm to 100 nm. Then, the ultraviolet colloidal quantum dot solution used for preparing the ultraviolet colloidal quantum dot film 132 is loaded into a spray gun, and a mask is placed above the CMOS quantum dot imaging chip. In this process, the mask can be used to prepare a film with a desired shape, and then the ultraviolet colloidal quantum dot solution is sprayed onto the chip through the mask until the thickness reaches 300 nm to 600 nm. When the ultraviolet colloidal quantum dot film 132 is prepared by using the photolithography method, similarly, first, a transparent bottom electrode is prepared by using a thermal evaporation method, and the thickness thereof can be 50 nm to 100 nm. Then, the ultraviolet colloidal quantum dot solution dissolved in a photosensitive ligand is spin-coated onto the surface of the entire CMOS quantum dot imaging chip. After that, the mask is placed above the CMOS quantum dot imaging chip, and ultraviolet light is used for exposure. After exposure, an organic solution is used to wash away the remaining quantum dots, and the above steps are repeated until the thickness of the ultraviolet colloidal quantum dot film 132 reaches 300 nm to 600 nm.

[0074] Exemplarily, Figure 5 A schematic diagram of photoluminescence and absorption spectrum of the ultraviolet colloidal quantum dot film is provided for the embodiments of the present disclosure. Referring to Figure 5 , wherein the horizontal axis X1 represents the wavelength, the unit is nm, and the vertical axis Y1 represents the photoluminescence / absorption spectrum. L61, L62, L63, L64, and L65 respectively represent CsPbI3, CsPbBr 1.5 I 1.5, CsPbBr3, CsPbCl1Br2, CsPbCl2Br1, the photoluminescence spectrum curve, L66, L67, L68, L69, L70 respectively represent CsPbI3, CsPbBr 1.5 I 1.5 , CsPbBr3, CsPbCl1Br2, CsPbCl2Br1, the absorption spectrum curve. It should be noted that the photoluminescence spectrum is the spectrum of visible light emitted by the ultraviolet colloidal quantum dot film after receiving ultraviolet light, and the absorption spectrum is the spectrum of visible light absorbed by the ultraviolet colloidal quantum dot film itself. Based on this, the figure shows the CsPbI3, CsPbBr 1.5 I 1.5 , CsPbBr3, CsPbCl1Br2, CsPbCl2Br1, the photoluminescence spectrum and the absorption spectrum corresponding to each of them, which shows that by changing the proportion of the reaction substance, the visible light wavelength band of the ultraviolet light received (i.e. photoluminescence) can be changed.

[0075] In combination with the foregoing, it should be noted that different colors of ultraviolet colloidal quantum dot films also have different absorption colors of visible light, for example, red ultraviolet colloidal quantum dot films absorb red visible light, and green ultraviolet colloidal quantum dot films absorb green visible light. Therefore, for different imaging environments with different visible light intensity distributions, different colors of ultraviolet colloidal quantum dot films can be selected for detection. In addition, for perovskite colloidal quantum dots with a chemical formula of CsPbX3 (X = Cl, Br, I), by changing the proportion of the reaction substance, the photoluminescence and absorption spectrum can be changed accordingly; for example, the photoluminescence and absorption spectrum of CsPbCl3 quantum dots are both purple (corresponding to a visible light wavelength of 400 nm); the photoluminescence and absorption spectrum of CsPb(Cl / Br)3 quantum dots are deep blue to blue spectrum (corresponding to a visible light wavelength of 420-500 nm); the photoluminescence and absorption spectrum of CsPbBr3 quantum dots are blue to green spectrum (corresponding to a visible light wavelength of 470-520 nm); the photoluminescence and absorption spectrum of CsPb(I / Br)3 quantum dots are green to red spectrum (corresponding to a visible light wavelength of 520-650 nm); and the photoluminescence and absorption spectrum of CsPbI3 quantum dots are red to deep red spectrum (corresponding to a visible light wavelength of 600-700 nm).

[0076] In some embodiments, Figure 6 a distribution diagram of a detection unit provided by an embodiment of the present disclosure, Figure 7 a distribution diagram of another detection unit provided by an embodiment of the present disclosure, Figure 6 and Figure 7Two arrangement structures are shown. The area of the vertical projection of the infrared light detection subunit 140 on the substrate 110 is equal to the area of the vertical projection of the ultraviolet colloidal quantum dot film 132 on the substrate 110, and the infrared light detection subunit 140 and the ultraviolet colloidal quantum dot film 132 are each arranged in a row and alternately arranged; or, each infrared light detection subunit 140 and each ultraviolet colloidal quantum dot film 132 are alternately arranged.

[0077] In some embodiments, referring to Figure 3 and Figure 4 , the infrared light detection subunit 140 includes: a first electrode 141, disposed on the side of the metal wiring layer 111 away from the substrate 110; an infrared sensing layer 142, disposed on the side of the first electrode 141 away from the metal wiring layer 111; and a second electrode 143, disposed on the side of the infrared sensing layer 142 away from the first electrode 141.

[0078] The overall structure of the infrared light detection subunit 140 is disposed on the surface of the chip, and the infrared detector for detecting the infrared light wave band based on the colloidal quantum dots is prepared by forming a colloidal quantum dot layer on the electrode. Specifically, the infrared detector corresponding to the infrared light detection subunit 140 can be a photoconductive infrared detector and a photovoltaic infrared detector, and when the infrared detector is prepared, the visible light detector 131 is a photovoltaic detector.

[0079] Illustratively, in the preparation of the infrared detector, the infrared sensing layer 142 in the structure thereof is different according to the structure of the photoconductive infrared detector and the photovoltaic infrared detector, and the colloidal quantum dots used by the infrared sensing layer 142 are fully compatible with the silicon-based readout circuit.

[0080] The first electrode 141 is a bottom electrode in the thin film structure of the infrared light detection subunit 140. Illustratively, in the preparation of the photoconductive infrared detector, the first electrode 141 and the second electrode 143 are both metal electrodes, and can be one or more of gold, silver, copper, aluminum, and chromium; in the preparation of the photovoltaic infrared detector, the first electrode 141 is a metal electrode, which can be one or more of gold, silver, copper, aluminum, and chromium, and the second electrode 143 is a transparent electrode, which can be one of indium tin oxide (ITO) and fluorine-doped tin dioxide (FTO). In other embodiments, other materials known to those skilled in the art can also be used to prepare the infrared detector, which will not be described or limited here.

[0081] In some embodiments, Figure 8 is a structural schematic diagram of an infrared light detection subunit provided by an embodiment of the present disclosure, Figure 9 is another structural schematic diagram of an infrared light detection subunit provided by an embodiment of the present disclosure, referring to Figure 8 and Figure 9The infrared sensing layer 142 includes: an intrinsic quantum dot layer 01; or, the infrared sensing layer 142 includes: a hole transport layer 02, a P-type quantum dot layer 03, an intrinsic quantum dot layer 01, an N-type quantum dot layer 04, and an electron transport layer 05, which are sequentially stacked along the direction from the first electrode 141 to the second electrode 143.

[0082] For example, with Figure 8 Taking the orientation and structure shown as an example, the intrinsic quantum dot layer 01 is formed above the first electrode 141; on this basis, a second electrode 143 is further arranged upward to form a photoconductive structure of an infrared detector.

[0083] For example, with Figure 9 Taking the orientation and structure shown as an example, the hole transport layer 02, the P-type quantum dot layer 03, the intrinsic quantum dot layer 01, the N-type quantum dot layer 04, and the electron transport layer 05 are sequentially formed above the first electrode 141; on this basis, a second electrode 143 is further arranged upward to form a photovoltaic structure of the infrared detector, that is, a vertically coupled photovoltaic infrared detector is formed along the direction from the first electrode 141 to the second electrode 143.

[0084] Specifically, hole transport layer O2 can be poly(3-hexylthiophene) (P3HT), poly(3,4-ethylenedioxythiophene)polystyrene sulfonate (PEDOT:PSS), 2,2',7,7'-tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9'-spirodifluorene (spiro-OMeTAD), polytriarylamine (PTAA), and nickel oxide (NiO). x) and PSS together greatly improves the solubility of PEDOT. The water-soluble conductive material is mainly applied to the hole transport layer 02. The P-type quantum dot layer 03 is one of P-type quantum dots of silver telluride (Ag2Te) and poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS), which is the same as the intrinsic quantum dot layer 01. The intrinsic quantum dot layer 01 is one of lead sulfide (PbS), lead selenide (PbSe), mercury telluride (HgTe), mercury selenide (HgSe), cadmium telluride (CdTe), and mercury cadmium telluride (HgCdTe) quantum dots. The N-type quantum dot layer 04 is one of bismuth selenide (Bi2Se3), bismuth sulfide (Bi2S3), bismuth telluride (Bi2Te3), zinc oxide (ZnO), and cadmium selenide (CdSe), which is the same as the intrinsic quantum dot layer 01. The electron transport layer 05 is one of zinc oxide (ZnO), titanium dioxide (TiO2), 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP), and butyl methyl carbonate (PCBM). In other embodiments, other materials can also be used to form the film layers of the photovoltaic infrared detector, which are not limited herein.

[0085] It should be noted that by adjusting the synthesis time and synthesis temperature of the infrared colloidal quantum dots (colloidal quantum dots prepared when the infrared sensing layer is prepared), the spectral range of the infrared light response can be accurately controlled, that is, the detection of different wavebands of infrared light can be realized, such as the detection of short-wave infrared, medium-wave infrared, and long-wave infrared, etc. The use of infrared colloidal quantum dot materials as a photoelectric sensitive material has the advantages of high sensitivity of colloidal quantum dots and strong light response and good performance of the device prepared by using colloidal quantum dots.

[0086] As known from the foregoing, colloidal quantum dots can be directly prepared on a substrate through liquid phase processing and can be prepared on a large scale. Based on the advantages of liquid phase processing and compatibility with a silicon substrate, the quantum dot film can be directly coupled with a silicon substrate readout circuit, overcoming the problems of complex preparation of existing infrared and ultraviolet bulk materials and incompatibility with a silicon substrate.

[0087] In some embodiments, the photovoltaic infrared detector formed has a hole transport layer with a thickness of 5 nm to 10 nm, a P-type quantum dot layer with a thickness of 50 nm to 200 nm, an intrinsic quantum dot layer with a thickness of 300 nm to 600 nm, an N-type quantum dot layer with a thickness of 50 nm to 200 nm, and an electron transport layer with a thickness of 5 nm to 10 nm.

[0088] Exemplarily, the thickness of the hole transport layer 02 can be 7 nm, 9 nm or other numerical values and numerical value ranges, the thickness of the P-type quantum dot layer 03 can be 50 nm, 70 nm or other numerical values and numerical value ranges, the thickness of the intrinsic quantum dot layer 01 can be 400 nm, 500 nm or 500-600 nm, or other numerical values and numerical value ranges, the thickness of the N-type quantum dot layer 04 can be 70 nm, 100 nm or 100-200 nm or other numerical values and numerical value ranges, and the thickness of the electron transport layer 05 can be 5 nm, 8 nm or 7-10 nm or other numerical values and numerical value ranges, all of which are not limited herein. Moreover, the quantum dots can be spatially controlled and patterned into a thin film by spraying and photolithography using a mask plate and prepared at the positions of the corresponding infrared light detection sub-units 140, which are not limited herein.

[0089] In some embodiments, the substrate 110 is a silicon-based readout circuit substrate including an array of pixel regions; each detection unit 120 is arranged in a corresponding pixel region; the infrared light detection sub-unit 140 is connected to the silicon-based readout circuit substrate via the metal wiring layer 111; the visible light detector 131 in the ultraviolet-visible light detection sub-unit 130 is arranged in the silicon-based readout circuit substrate or connected to the silicon-based readout circuit substrate via the metal wiring layer 111.

[0090] The silicon-based readout circuit substrate is a circuit substrate for transmitting the electrical signal generated by the photoelectric effect, and the specific specifications of the silicon-based readout circuit substrate are not limited herein.

[0091] Each detection unit 120 is arranged in a corresponding pixel region, i.e., each detection unit 120 and each pixel region are one-to-one corresponding and arranged in an array. On this basis, the infrared light detection sub-unit 140 connected to the silicon-based readout circuit substrate via the metal wiring layer 111, and the visible light detector 131 arranged in the silicon-based readout circuit substrate or connected to the silicon-based readout circuit substrate via the metal wiring layer 111 are formed.

[0092] In some embodiments, the silicon-based readout circuit substrate further includes: a timing control circuit (not shown in the figure) for resetting the circuit and collecting the voltage signal generated by the photoelectric response and filtering out the noise signal based on the set incident light irradiation time; a readout logic circuit (not shown in the figure) for selecting and amplifying the voltage signal of the row pixel region and column pixel region overlap and then reading out; a signal processing circuit (not shown in the figure) connected to the silicon-based readout circuit substrate; wherein the signal processing circuit is used to form the detection imaging of visible light, ultraviolet light and infrared light based on the voltage signal generated by the photoelectric response transmitted by the silicon-based readout circuit substrate.

[0093] It should be noted that in the prior art, CMOS (Complementary Metal Oxide Semiconductor) is a mainstream semiconductor process, which has the advantages of low power consumption and high speed, and is widely used in the manufacture of CPUs, memories and various digital logic chips. The CMOS image sensor prepared thereby has simple structure, multiple processing functions, high yield and the ability to access any unit. In addition, based on the CMOS process, the photosensitive array, the driver, the column driver, the timing control logic, the AD converter, the data bus output interface and the control interface can be integrated on a silicon wafer (or a collection of readout circuit substrates), realizing the detection imaging of visible light. Its working process can generally be divided into reset, photoelectric conversion, integration and readout.

[0094] In combination with the foregoing, the timing control circuit can be combined with the readout logic circuit, and the time of incident light irradiation (or exposure) needs to be set in advance in the timing control process. It should be noted that the voltage signal read out for the first time contains the light signal generated in the circuit during illumination (i.e., the voltage signal generated based on the photoelectric response) and the dark signal that originally exists in the circuit without illumination. The voltage signal read out for the second time is only the dark signal that originally exists in the circuit without illumination, i.e., noise. Finally, by subtracting the voltage signals read out for the two times, the noise in the signal is removed. In this way, the influence of most of the noise can be eliminated, and the imaging quality can be improved.

[0095] In combination with the foregoing, the process of reading out the imaging signal by the readout logic circuit is specifically as follows: an electric charge or voltage amplifier is built in each pixel region to convert the number of charges generated based on the photoelectric response in the pixel potential well into a voltage signal. The readout logic selects a certain row, and the output signals of the charge or voltage amplifiers of all pixel regions in the row are connected to the column output signal. Then the readout logic continues to select a certain column pixel region, and the column signal is connected to the programmable output amplifier. After the above operations, the voltage signal of the selected pixel region is amplified by a certain multiple. The amplified voltage signal is converted into a digital signal by an AD converter (analog-to-digital converter). In this way, the signals corresponding to the visible light generated by the photoluminescence of ultraviolet light, the directly incident visible light and the infrared light are respectively converted and read out through row selection and column selection.

[0096] In combination with the foregoing, the process of processing the imaging signal by the signal processing circuit is as follows: after the voltage signal generated by the photoelectric response is converted into a digital signal by the readout logic circuit, the digital signal is further processed by an image signal processor inside the silicon readout circuit substrate, and is output to the outside through a certain interface protocol. After the signal processing, the imaging signals formed by the ultraviolet light band, the visible light band and the infrared light band are fused to realize the imaging detection of the ultraviolet light band, the visible light band and the infrared light band.

[0097] Thus, the photoelectric detector such as the infrared detector and the visible light detector based on the ultraviolet colloidal quantum dot film can realize the conversion of the optical signal to the electrical signal, and the CMOS imaging chip has the functions of selection, integration and amplification, integrates and reads out the electrical signal output by the detector, and finally converts the digital signal output to the outside, thereby realizing imaging.

[0098] The CMOS quantum dot imaging chip provided by the embodiments of the present disclosure comprises a substrate 110; a detection unit 120 arranged on one side of the substrate 110 and arranged in an array; the detection unit 120 comprises an ultraviolet-visible light detection subunit 130 and an infrared light detection subunit 140; the vertical projection of the ultraviolet-visible light detection subunit 130 on the substrate 110 is staggered with the vertical projection of the infrared light detection subunit 140 on the substrate 110; the ultraviolet-visible light detection subunit 130 is used for outputting corresponding electrical signals in response to the incident ultraviolet light and the incident visible light; and the infrared light detection subunit 140 is used for outputting corresponding electrical signals in response to the infrared light. Thus, on the basis of the existing detection visible light CMOS imaging chip, the ultraviolet-visible light detection subunit and the infrared light detection subunit are combined into the same chip, the ultraviolet light and infrared light detection waveband is expanded, and the imaging detection of the ultraviolet-visible light-infrared light wide spectrum is realized.

[0099] In combination with the above, after the chip is redesigned, the wide spectrum detection imaging of the ultraviolet light waveband, the visible light waveband and the infrared light waveband can be realized, and the CMOS quantum dot imaging chip has the advantages of simple preparation, low material processing cost, wide detection waveband, strong light response, low application cost and easy mass production automation, and can be widely applied in the field of imaging detection.

[0100] Exemplarily, Figure 10 A comparison diagram of infrared responses before and after the preparation of the infrared light detection subunit provided by the embodiments of the present disclosure is shown. As can be seen from the diagram, Figure 10 It can be seen that, the horizontal axis X2 represents time, with the unit of millisecond (ms), and the vertical axis Y2 represents the response signal voltage, with the unit of volt (V); in addition, 55 represents the infrared (light) channel (corresponding to the infrared light detection subunit), and 54 represents the visible light channel (corresponding to the visible light detector). As can be seen from the diagram, the CMOS imaging chip without the infrared channel and only with the visible light channel has no response to the infrared light, and the response signal voltage value of the straight line segment corresponding to 54 in the diagram is zero; after the infrared channel is prepared, it has obvious response to the infrared light, and the line segment corresponding to 55 in the diagram, i.e. the voltage signal responding to the infrared light is periodically generated in the corresponding time period, so that it can detect the infrared waveband which cannot be detected originally.

[0101] Exemplarily, Figure 11A UV response comparison schematic diagram before and after preparation of the UV colloidal quantum dot film is provided for the embodiment of the present disclosure. The UV response comparison schematic diagram before and after preparation of the UV colloidal quantum dot film is shown in FIG. 6. Figure 11 It can be seen that, the horizontal axis X3 represents time, with the unit of millisecond (ms), and the vertical axis Y3 represents response signal voltage, with the unit of volt (V); in addition, 57 represents a visible light channel (corresponding to a visible light detector), and 56 represents a UV-Vis channel (corresponding to a UV-Vis detector subunit). As can be seen from the figure, the CMOS imaging chip without the UV-Vis channel and only with the visible light channel has no response to the UV light, which is represented by the line segment corresponding to 57 in the figure; after the UV-Vis channel is prepared, it has a clear response to the UV light, which is represented by the line segment corresponding to 56 in the figure, i.e., periodically generates a voltage signal in response to the UV light in the corresponding time period, so that it can detect the UV band that cannot be detected originally.

[0102] On the basis of the above-mentioned embodiments, the present disclosure further provides a preparation method of a CMOS quantum dot imaging chip, which is used for preparing any one of the above-mentioned CMOS quantum dot imaging chips and has corresponding beneficial effects.

[0103] In some embodiments, Figure 12 A flowchart of the preparation method of the CMOS quantum dot imaging chip is provided for the embodiment of the present disclosure. Referring to FIG. 7, Figure 12 The method comprises the following steps:

[0104] S21, providing a substrate.

[0105] In combination with the above, the substrate can be a silicon-based readout circuit substrate and can be prepared by using a CMOS flow process; in other embodiments, the substrate can also be prepared by using other process steps, which are not limited herein.

[0106] S22, forming an array-arranged detection unit on one side of the substrate.

[0107] The detection unit comprises a UV-Vis detector subunit and an infrared light detector subunit; the vertical projection of the visible light detector subunit on the substrate is staggered with the vertical projection of the infrared light detector subunit on the substrate; the UV-Vis detector subunit is used for responding to incident UV light and incident visible light to output corresponding electrical signals; and the infrared light detector subunit is used for responding to infrared light to output corresponding electrical signals.

[0108] In combination with the above, forming the UV-Vis detector subunit specifically comprises: preparing a visible light detector in the CMOS flow process stage of the silicon-based readout circuit substrate, then preparing a transparent bottom electrode on the chip surface in a way of thermal evaporation, and then forming a UV colloidal quantum dot film on the transparent bottom electrode in a way of spraying, photolithography or other ways.

[0109] After the preparation of the ultraviolet-visible light detection subunit is completed, the infrared detector corresponding to the infrared light detection subunit is prepared in the corresponding pixel area, including: first, a first electrode such as a metal electrode is evaporated onto the substrate by thermal evaporation, then a patterned quantum dot film is formed above the first electrode by using etching, spraying or photolithography process, and finally a second electrode is formed above the film layer. Among them, after the CMOS flow process is completed, the infrared detector can be directly coupled to the chip through liquid phase treatment.

[0110] Among them, since the infrared detector corresponding to the infrared light detection subunit can be a photoconductive infrared detector and a photovoltaic infrared detector, the preparation method used when forming the quantum dot film is different, specifically:

[0111] Figure 13 A device for preparing an infrared detector and an ultraviolet colloidal quantum dot film by spraying method is provided for the embodiments of the present disclosure. Referring to Figure 13 , the heating plate 30, the detector substrate 31, the mask plate 32 and the spray gun 33 filled with colloidal quantum dot solution are shown in the figure, wherein: the heating plate 30 is used for heating the detector substrate 31, and the mask plate 32 is covered on the side of the detector substrate 31 facing the spray gun 33 filled with colloidal quantum dot solution. When preparing a patterned quantum dot film by spraying method, for the infrared detector of photoconductive structure, first, the colloidal quantum dot solution is filled into the spray gun, the mask plate 32 is placed above the detector substrate 31 (or CMOS quantum dot imaging chip), and the colloidal quantum dot is sprayed onto the CMOS quantum dot imaging chip through the mask plate 32 until the thickness range reaches 300nm-600nm. For the infrared detector of photovoltaic structure, first, the mask plate 32 is placed above the CMOS quantum dot imaging chip, the solution corresponding to the hole transport layer is sprayed onto the CMOS quantum dot imaging chip until the thickness range reaches 5nm-10nm, then the P-type quantum dot solution is sprayed onto the CMOS quantum dot imaging chip until the thickness range reaches 50nm-200nm; then the intrinsic quantum dot solution is sprayed onto the CMOS quantum dot imaging chip until the thickness range reaches 300nm-600nm; then the N-type quantum dot solution is sprayed onto the CMOS quantum dot imaging chip until the thickness range reaches 50nm-200nm; finally, the solution corresponding to the electron transport layer is sprayed onto the CMOS quantum dot imaging chip until the thickness range reaches 5nm-10nm.

[0112] Figure 14 A process diagram for preparing an infrared detector and an ultraviolet colloidal quantum dot film by photolithography method is provided for the embodiments of the present disclosure. Referring to Figure 14 , 34 represents colloidal quantum dot solution, 35 represents CMOS wafer, 36 represents mask plate, 37 represents patterned quantum dot film, and 38 represents ultraviolet light. Specifically:

[0113] In the preparation of the patterned quantum dot film by using the photolithography method, for the infrared detector of the light guide type structure, firstly, the colloidal quantum dot solution dissolved in the photosensitive ligand is spin-coated on the surface of the CMOS quantum dot imaging chip, then the mask plate is placed above the CMOS quantum dot imaging chip, the ultraviolet light is used for exposure, and the remaining quantum dots are washed away by using the organic solution, and the above steps are repeated until the thickness of the quantum dots ranges from 300 nm to 600 nm. For the infrared detector of the photovoltaic type structure, firstly, the solution corresponding to the hole transport layer is spin-coated on the CMOS quantum dot imaging chip, and the thickness can be 5 nm to 10 nm, then the P-type quantum dot solution is spin-coated on the CMOS quantum dot imaging chip until the thickness is 50 nm to 200 nm, then the intrinsic quantum dot solution dissolved in the photosensitive ligand is spin-coated on the wafer, after that, the mask plate is placed above the CMOS quantum dot imaging chip, the ultraviolet light is used for exposure, and the remaining quantum dots are washed away by using the organic solution, and the above operation is repeated until the thickness of the intrinsic quantum dots ranges from 300 nm to 600 nm, then the N-type quantum dot solution is spin-coated on the CMOS quantum dot imaging chip until the thickness is 50 nm to 200 nm, and finally, the solution corresponding to the electron transport layer is spin-coated on the CMOS quantum dot imaging chip until the thickness is 5 nm to 10 nm.

[0114] It should be noted that, compared with other photosensitive materials, the colloidal quantum dots have the advantages of adjustable optical properties, liquid phase processing and compatibility with silicon-based substrates, etc., so that the colloidal quantum dots in the liquid phase can be prepared on the substrate to form a device, i.e., the colloidal quantum dot film structure and the readout circuit can be directly coupled for signal coupling, which is not only simple to operate, but also suitable for large-scale preparation, greatly reducing the material processing cost. Based on the fact that the colloidal technology can be operated at low cost and easily expanded, it has been widely used in the fields of optical detection and photovoltaic power generation, etc.

[0115] In addition, in the process of preparing the photoelectric detector using the colloidal quantum dots as the infrared photosensitive material, by changing the reaction temperature, reaction time and reactant ratio during the synthesis of the quantum dots, the wavelength range of the quantum dot response can be accurately adjusted as needed to realize the accurate detection of different target wavelength ranges such as near-infrared, short-wave infrared, medium-wave infrared, long-wave infrared and terahertz, i.e., the error between the response peak of the detector and the target wavelength range is not more than ±0.1 um. In addition, on the basis that the chip can meet the requirements of the back incidence and the normal incidence structures, by changing the response wavelength of the quantum dots, the infrared of different wavelengths can be imaged, and the application scenarios are more widely used.

[0116] Exemplarily, when the reaction temperature is controlled to be 60°C and the reaction time is 4 minutes, short-wave infrared quantum dots with an absorption wavelength of 1.6 um can be synthesized; when the reaction temperature is controlled to be 80°C and the reaction time is 4 minutes, short-wave infrared quantum dots with an absorption wavelength of 2.5 um can be synthesized; when the reaction temperature is controlled to be 100°C and the reaction time is 6 minutes, medium-wave infrared quantum dots with an absorption wavelength of 3.5 um can be synthesized; when the reaction temperature is controlled to be 100°C and the reaction time is 16 minutes, medium-wave infrared quantum dots with an absorption wavelength of 5 um can be synthesized; and when the reaction temperature is controlled to be 100°C and the reaction time is 40 minutes, long-wave infrared quantum dots with an absorption wavelength of 7 um can be synthesized.

[0117] Meanwhile, the synthesis process of the colloidal quantum dots is simple, liquid materials can be converted into solid functional thin films through a low-cost liquid-phase processing process, and the colloidal quantum dots can be directly coupled with a silicon-based readout circuit without the need for expensive flip-chip bonding and molecular beam epitaxy processes, thereby further reducing the material processing cost. Based on the above advantages, the colloidal quantum dots can be used to mass-produce detectors. For example, the liquid-phase process and silicon-based compatibility advantage of the quantum dot thin film enables the quantum dot thin film to be directly coupled with a CMOS silicon-based readout circuit, thereby overcoming the problems of complex preparation of bulk infrared and ultraviolet materials and incompatibility with the silicon-based readout circuit in the prior art.

[0118] The preparation method of the CMOS quantum dot imaging chip provided by the embodiments of the present disclosure forms an array of detection units on one side of a substrate. The detection units include ultraviolet-visible light detection sub-units and infrared light detection sub-units. The vertical projection of the visible light detection sub-units on the substrate is staggered with the vertical projection of the infrared light detection sub-units on the substrate. The ultraviolet-visible light detection sub-units are used to output corresponding electrical signals in response to incident ultraviolet light and incident visible light. The infrared light detection sub-units are used to output corresponding electrical signals in response to infrared light. Thus, based on the structure formed by the above steps, the ultraviolet-visible light detection sub-units and the infrared light detection sub-units are combined into the same chip on the basis of the existing detection visible light CMOS imaging chip, thereby expanding the detection wavelength band of ultraviolet light and infrared light and realizing wide-spectrum imaging detection of ultraviolet light, visible light, and infrared light.

[0119] In some embodiments, the detection units are formed by using a CMOS flow method and a film layer stacking deposition method to form the ultraviolet-visible light detection sub-units and using the film layer stacking deposition method to form the infrared light detection sub-units.

[0120] In the process of forming the ultraviolet-visible light detection subunit, first, a visible light detector is prepared by a CMOS flow method, then a transparent bottom electrode is formed on the surface of the chip corresponding to the visible light detector by thermal evaporation, and then a thin film of colloidal quantum dots is stacked on the transparent bottom electrode by spraying or photolithography.

[0121] In the process of forming the infrared light detection subunit, the infrared light detection subunit is formed by stacking the film layers, i.e., the vertical coupling structure.

[0122] For the photoconductive infrared detector, when the light irradiates the photosensitive region (the infrared light detection subunit and the visible light detection subunit) of the detector, the photo-generated electron-hole pairs are generated in the photosensitive region of the detector, and the holes and the electrons diffuse to the top layer and the bottom layer of the electrode under the action of an external voltage (usually 0-15V).

[0123] For the photovoltaic infrared detector, because the N-type quantum dot layer and the P-type quantum dot layer in the doped state are arranged, the built-in potential is formed in the detector, and when the light irradiates the photosensitive region of the detector, the photo-generated electron-hole pairs can be separated under the action of the built-in potential, and the holes diffuse to the transparent electrode (the second electrode) and the electrons diffuse to the metal electrode (the first electrode).

[0124] Therefore, for the infrared light detection subunit, when the infrared light source irradiates the corresponding pixel photosensitive region, the photo-generated electrons generated in the photosensitive region can be collected by the potential well under the action of the external electric field, converted into a voltage signal, and read out, thereby realizing the conversion from the optical signal to the electrical signal.

[0125] Figure 15 A performance comparison diagram of the photoconductive infrared detector and the photovoltaic infrared detector is provided for the embodiments of the present disclosure, in which the horizontal axis X4 represents the temperature in Kelvin (K), and the vertical axis Y4 represents the specific detectivity in Jones; L38 and L39 represent the performance curves of the photoconductive (PC type) and photovoltaic (PV type) infrared detectors, respectively. It can be seen that Figure 15 It can be seen that the sensitivity and the signal-to-noise ratio of the photovoltaic (PV type) infrared detector are greatly improved when it works without an external bias. On this basis, the electron transport layer and the hole transport layer arranged are more conducive to the transport of electrons and holes, and further improve the performance of the detector.

[0126] In some embodiments, Figure 16 A flowchart for forming the infrared light detection subunit is provided for the embodiments of the present disclosure, with reference to Figure 16 forming the infrared light detection subunit, comprising:

[0127] S41, forming a first electrode on a side of the metal wiring layer away from the substrate.

[0128] In combination with the above, the infrared light detection subunit is connected to the side of the metal wiring layer away from the substrate. Exemplarily, the material of the metal wiring layer is one or more of copper, aluminum, and gold, and other materials known to those skilled in the art can also be used, and is prepared based on a tape-out process, which is not limited here.

[0129] The first electrode can be a metal electrode and can be evaporated onto the substrate by thermal evaporation, and the thickness thereof can be 50 nm to 100 nm. In other embodiments, other formation methods known to those skilled in the art can also be used, which are not limited here.

[0130] S42, forming an infrared sensing layer on a side of the first electrode away from the substrate.

[0131] The specific structure of the formed infrared sensing layer is different according to the type of the infrared detector corresponding to the infrared light detection subunit, i.e., based on a photoconductive infrared detector and a photovoltaic infrared detector, different colloidal quantum dot films are prepared and a vertical coupling structure is formed, which can be prepared by spraying, photolithography, or other methods, which are not limited here.

[0132] S43, forming a second electrode on a side of the infrared sensing layer away from the first electrode.

[0133] The second electrode is arranged above the formed infrared sensing layer, and when the second electrode is a metal electrode or a transparent electrode, it can be evaporated by thermal evaporation. Exemplarily, when the transparent electrode is prepared, the thickness thereof can be 20 nm to 40 nm.

[0134] In some embodiments, the preparation method further includes: providing a silicon-based readout circuit substrate; the silicon-based readout circuit substrate includes pixel regions arranged in an array; forming a first electrode includes: forming a first electrode in a pixel region corresponding to an infrared light detection subunit of the silicon-based readout circuit substrate based on a thermal evaporation method; forming an infrared sensing layer includes: forming an infrared sensing layer on a side of the first electrode away from the silicon-based readout circuit substrate based on at least one of etching, spraying, and photolithography; and forming a second electrode includes: forming a second electrode on a side of the infrared sensing layer away from the first electrode based on a thermal evaporation method.

[0135] In the preparation of the light guide type infrared detector corresponding to the infrared light detection subunit, the first electrode and the second electrode can both be metal electrodes, and in the preparation of the photovoltaic type infrared detector corresponding to the infrared light detection subunit, the first electrode can be a metal electrode and the second electrode can be a transparent electrode. In the formation of the infrared light detection subunit, either of the light guide type and the photovoltaic type infrared detector can be prepared.

[0136] On the basis of the above-mentioned embodiments, the disclosure further provides a driving method of the CMOS quantum dot imaging chip, which is used for driving any one of the above-mentioned CMOS quantum dot imaging chips.

[0137] In some embodiments, Figure 17 A flowchart of a CMOS quantum dot imaging chip driving method provided by the disclosure is shown in FIG. 6. Referring to FIG. 6, Figure 17 The method comprises the following steps.

[0138] S51, resetting the circuit by using the timing control circuit and collecting the voltage signal generated by the photoelectric response and filtering out the noise signal based on the set incident light irradiation time.

[0139] S52, selecting the voltage signal overlapped by the row pixel region and the column pixel region by using the readout logic circuit and reading out after amplification.

[0140] S53, forming the detection imaging of the visible light, ultraviolet light and infrared light by using the signal processing circuit based on the voltage signal generated by the photoelectric response transmitted by the silicon-based readout circuit substrate.

[0141] Thus, the CMOS quantum dot imaging chip overcomes the limitation that only visible light band can be detected in the existing CMOS imaging chip, and realizes the wide spectrum imaging of the ultraviolet light-visible light-infrared light with fast response speed, low noise and high image quality.

[0142] Exemplarily, Figure 18 A visible light detector and an ultraviolet-visible light detection subunit imaging contrast diagram provided by the disclosure is shown in FIG. 7. Referring to FIG. 7, Figure 18 , Figure 18The effects of imaging of the visible light detector and the ultraviolet-visible light detection subunit under ultraviolet lamp irradiation are shown in FIG. 7, wherein 71 represents a photograph taken by a mobile phone, 72 represents the imaging effect when only the visible light detector is prepared, and 73 represents the imaging effect of the ultraviolet-visible light detection subunit. According to the working principle of the ultraviolet-visible light detection subunit, the ultraviolet colloidal quantum dot film will produce photoluminescence after ultraviolet irradiation, that is, the ultraviolet waveband is absorbed by the film, and the film itself will radiate light, so it is not a photodetector. According to the above working principle, when the ultraviolet colloidal quantum dot film is spin-coated onto the surface of the chip corresponding to the visible light detector, the ultraviolet colloidal quantum dot film will absorb ultraviolet light and emit visible light itself, realizing down-conversion and conversion into visible light in the process, that is, converting light with strong energy and short wavelength into light with weak energy and long wavelength, and then the visible light detector receives the converted visible light and converts it into an electrical signal, thereby forming an ultraviolet-visible light channel corresponding to the ultraviolet-visible light detection subunit, so that the visible light CMOS imaging chip that cannot detect the ultraviolet waveband can detect the ultraviolet waveband, thereby widening the detection range of the existing silicon-based CMOS imaging chip.

[0143] Exemplarily, Figure 19 An ultraviolet-visible light-infrared light three-color imaging effect schematic diagram is provided in the embodiments of the present disclosure. Referring to Figure 19 , wherein 74 represents a photograph taken by a mobile phone, 75 represents an ultraviolet light imaging effect schematic diagram, 76 represents a visible light imaging effect schematic diagram, 77 represents an infrared light imaging effect schematic diagram, 78 represents a result schematic diagram of ultraviolet-visible light-infrared light imaging together, and 79 represents a red part at the top end of an electric iron. It should be noted that in the diagram represented by 78, the silicon wafer cannot transmit visible light but can transmit infrared light, so that the outline of the silicon wafer in the visible light imaging shown by 76 can be seen in the imaging result, and the electric iron behind the silicon wafer in the infrared light imaging shown by 77 can also be seen. Since the infrared waveband contains temperature information, the gray value of the electric iron in the imaging result is obviously higher than that of other parts, the red part at the top end of the electric iron shown by 79 can be seen, and the photoluminescence visible light formed after the ultraviolet colloidal quantum dot film is irradiated by the ultraviolet lamp, that is, the ultraviolet light imaging shown by 75, can also be captured by the detector and presented in the image. Therefore, by horizontally coupling the ultraviolet-visible light detection subunit and the infrared light detection subunit in the CMOS quantum dot imaging chip in the embodiments of the present disclosure, the CMOS quantum dot imaging chip for ultraviolet-visible light-infrared light three-color imaging is formed, which overcomes the limitation that the existing visible light CMOS imaging chip can only detect the visible light waveband, realizes ultraviolet-visible light-infrared light three-color wide spectrum imaging with fast response speed, low noise and high image quality, and makes the application scenarios more extensive.

[0144] 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.

[0145] 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 CMOS quantum dot imaging chip, characterized in that, include: Base; The detection units are disposed on one side of the substrate and arranged in an array; The detection unit includes an ultraviolet-visible light detection subunit and an infrared light detection subunit; the vertical projection of the ultraviolet-visible light detection subunit on the substrate and the vertical projection of the infrared light detection subunit on the substrate are offset; the ultraviolet-visible light detection subunit is used to output corresponding electrical signals in response to incident ultraviolet light and incident visible light; the infrared light detection subunit is used to output corresponding electrical signals in response to infrared light. A metal wiring layer, wherein the infrared light detection subunit is connected to the side of the metal wiring layer opposite to the substrate; The ultraviolet-visible light detection subunit includes: A visible light detector is disposed on the side of the substrate facing the metal wiring layer, or on the side of the metal wiring layer away from the substrate, for receiving visible light and converting it into a corresponding electrical signal; An ultraviolet colloidal quantum dot film is disposed on one side of the incident surface of the visible light detector to absorb incident ultraviolet light and generate visible light through photoluminescence or transmit incident visible light. A transparent bottom electrode is disposed on the side of the ultraviolet colloidal quantum dot film facing the visible light detector; The visible light detector is configured in a one-to-one correspondence with the ultraviolet colloidal quantum dot film; The area of ​​the infrared light detection subunit projected vertically onto the substrate is equal to the area of ​​the ultraviolet colloidal quantum dot film projected vertically onto the substrate, and the infrared light detection subunit and the ultraviolet colloidal quantum dot film are each arranged in a row, and are arranged alternately. or, Each of the infrared light detection subunits and each of the ultraviolet colloidal quantum dot films are arranged alternately.

2. The CMOS quantum dot imaging chip according to claim 1, characterized in that, The ultraviolet colloidal quantum dot film is used for photoluminescence transmission in the first wavelength band and for photoluminescence in the second wavelength band. The first band belongs to the visible light band, and the second band belongs to the ultraviolet light band.

3. The CMOS quantum dot imaging chip according to any one of claims 1-2, characterized in that, The infrared light detection subunit includes: The first electrode is disposed on the side of the metal wiring layer opposite to the substrate; An infrared sensing layer is disposed on the side of the first electrode opposite to the metal wiring layer; The second electrode is disposed on the side of the infrared sensing layer opposite to the first electrode.

4. The CMOS quantum dot imaging chip according to claim 3, characterized in that, The infrared sensing layer includes: an intrinsic quantum dot layer; or, The infrared sensing layer includes: A hole transport layer, a P-type quantum dot layer, an intrinsic quantum dot layer, an N-type quantum dot layer, and an electron transport layer are sequentially stacked along the direction from the first electrode to the second electrode.

5. The CMOS quantum dot imaging chip according to claim 4, characterized in that, The thickness of the hole transport layer is 5nm to 10nm; The thickness of the P-type quantum dot layer is 50 nm to 200 nm; The thickness of the intrinsic quantum dot layer is 300 nm to 600 nm; The thickness of the N-type quantum dot layer is 50 nm to 200 nm. The thickness of the electron transport layer is 5nm to 10nm.

6. The CMOS quantum dot imaging chip according to any one of claims 1-2, characterized in that, The substrate is a silicon-based readout circuit substrate, including an array of pixel regions; Each of the detection units is disposed within a corresponding pixel region; The infrared light detection subunit is connected to the silicon-based readout circuit substrate via the metal wiring layer; The visible light detector in the ultraviolet-visible light detection subunit is disposed within the silicon-based readout circuit substrate, or is connected to the silicon-based readout circuit substrate via the metal wiring layer.

7. The CMOS quantum dot imaging chip according to claim 6, characterized in that, The silicon-based readout circuit substrate also includes: The timing control circuit is used to reset the circuit and, based on the set incident light irradiation time, acquire the voltage signal generated by the photoelectric response and filter out the noise signal; The readout logic circuit is used to select the voltage signal that overlaps between the row pixel region and the column pixel region, amplify it, and then read it out. A signal processing circuit is connected to the silicon-based readout circuit substrate; wherein the signal processing circuit is used to form a detection and imaging of visible light, ultraviolet light and infrared light based on the voltage signal generated by the photoelectric response transmitted by the silicon-based readout circuit substrate.

8. A method for fabricating a CMOS quantum dot imaging chip, characterized in that, The method is used to prepare the CMOS quantum dot imaging chip according to any one of claims 1-7; the method includes: Provide a base; An array of detection units is formed on one side of the substrate; the detection unit includes an ultraviolet-visible light detection subunit and an infrared light detection subunit; the vertical projections of the ultraviolet-visible light detection subunits on the substrate and the vertical projections of the infrared light detection subunits on the substrate are offset; the ultraviolet-visible light detection subunits are used to output corresponding electrical signals in response to incident ultraviolet light and incident visible light; the infrared light detection subunits are used to output corresponding electrical signals in response to infrared light.

9. The method according to claim 8, characterized in that, The detection unit comprises: The ultraviolet-visible light detection subunit is formed using CMOS fabrication and film stacking deposition methods. The infrared light detection subunit is formed by film stacking deposition.

10. The method according to claim 9, characterized in that, The infrared light detection subunit comprises: A first electrode is formed on the side of the metal wiring layer opposite to the substrate; An infrared sensing layer is formed on the side of the first electrode opposite to the substrate; A second electrode is formed on the side of the infrared sensing layer opposite to the first electrode.

11. The method according to claim 10, characterized in that, Also includes: Provides silicon-based readout circuit substrates; The silicon-based readout circuit substrate includes an array of pixel regions; The formation of the first electrode includes: forming the first electrode in the pixel region corresponding to the infrared light detection subunit of the silicon-based readout circuit substrate by thermal evaporation. The formation of the infrared sensing layer includes: forming the infrared sensing layer on the side of the first electrode away from the silicon-based readout circuit substrate based on at least one of etching, spraying, and photolithography. The formation of the second electrode includes: forming the second electrode on the side of the infrared sensing layer opposite to the first electrode by means of thermal evaporation.

12. A driving method for a CMOS quantum dot imaging chip, characterized in that, The method is used to drive the CMOS quantum dot imaging chip according to any one of claims 1-7; the method includes: The timing control circuit resets the circuit and, based on the set incident light irradiation time, acquires the voltage signal generated by the photoelectric response and filters out the noise signal. The voltage signal where the row pixel region and column pixel region overlap is selected by the readout logic circuit, amplified, and then read out. The voltage signal generated by the photoelectric response transmitted on the substrate is used to form a detection image of visible light, ultraviolet light and infrared light using a signal processing circuit.

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