Short-wave infrared focal plane sensor and manufacturing method thereof, short-wave infrared detector

Abstract

The embodiment of the present application provides a short-wave infrared focal plane sensor, a manufacturing method thereof and a short-wave infrared detector. The short-wave infrared focal plane sensor comprises a TFT backplane and a colloidal quantum dot photoelectric conversion layer arranged on the TFT backplane. The orthographic projection of the colloidal quantum dot photoelectric conversion layer on the TFT backplane covers the sensing area of the TFT backplane and is used for sensing short-wave infrared light. The TFT backplane comprises a substrate base plate and a thin film transistor layer arranged on the sensing area of the substrate base plate. The thin film transistor layer is arranged between the substrate base plate and the colloidal quantum dot photoelectric conversion layer and comprises a plurality of thin film transistors. Each thin film transistor corresponds to a pixel. The side of the colloidal quantum dot photoelectric conversion layer facing the TFT backplane is provided with a plurality of bias electrodes, and the side of the colloidal quantum dot photoelectric conversion layer facing away from the TFT backplane is provided with a common electrode. Each bias electrode corresponds to a thin film transistor. The common electrode covers the colloidal quantum dot photoelectric conversion layer, and the common electrode and the bias electrode are made of the same material.

Description

Technical Field

[0001] The present application relates to the field of infrared imaging technology, and in particular to a short-wave infrared focal plane sensor and a manufacturing method thereof, and a short-wave infrared detector. Background Art

[0002] With the development of modern science, people have come to realize that objects with temperatures other than absolute zero will radiate electromagnetic waves, and that at room temperature, most objects radiate in the infrared band. Consequently, infrared radiation imaging has become a new detection method. Infrared imaging technology uses infrared photoelectric systems to convert received infrared radiation into photoelectric images that are perceptible to the human eye. The infrared spectrum is divided into: near-infrared, short-wave infrared, medium-wave infrared, long-wave infrared, and even long-wave infrared, far-infrared, and submillimeter waves. The wavelength range of near-infrared is 0.76 to 1.1 microns, short-wave infrared is 1 to 3 microns, medium-wave infrared is 3 to 6 microns, long-wave infrared is 6 to 15 microns, long-wave infrared is 15 to 30 microns, far-infrared is 30 to 100 microns, and submillimeter waves is 100 to 1000 microns. The infrared spectrum lies between the visible and microwave spectrums, and short-wave infrared imaging combines the characteristics of both visible light reflection imaging and long-wave infrared imaging. It has broad application prospects in low-light-level night vision, haze imaging, food color sorting, and semiconductor testing. Visible light imaging can reveal shadows and contrast, while long-wave infrared imaging captures information about molecular vibrations and thermal properties.

[0003] At present, traditional short-wave infrared focal plane sensors generally use indium gallium arsenide materials. The prepared detector array is interconnected with the silicon-based readout circuit through an indium column flip-chip bonding process. The cost of semiconductor epitaxial growth is high and the flip-chip bonding efficiency is low, resulting in the high cost of short-wave infrared focal plane sensors prepared with indium gallium arsenide materials, which seriously affects the widespread application of short-wave infrared focal plane sensors. Summary of the Invention

[0004] The purpose of the embodiments of the present invention is to provide a shortwave infrared focal plane sensor and a shortwave infrared detector to reduce the production cost of the shortwave infrared focal plane sensor. The specific technical solution is as follows:

[0005] According to a first aspect of an embodiment of the present application, there is provided a short-wave infrared focal plane sensor, comprising a TFT backplane and a colloidal quantum dot photoelectric conversion layer provided on the TFT backplane, wherein the orthographic projection of the colloidal quantum dot photoelectric conversion layer on the TFT backplane covers the sensing area of ​​the TFT backplane, and the colloidal quantum dot photoelectric conversion layer is used to sense short-wave infrared light; the TFT backplane comprises a base substrate and a thin-film transistor layer provided in the sensing area of ​​the base substrate; the thin-film transistor layer is provided between the base substrate and the colloidal quantum dot photoelectric conversion layer, and the thin-film transistor layer comprises a plurality of thin-film transistors, each thin-film transistor corresponding to a pixel; the colloidal quantum dot photoelectric conversion layer is provided with a plurality of bias electrodes on a side facing the TFT backplane, each bias electrode corresponding to a thin-film transistor; a common electrode is provided on a side of the colloidal quantum dot photoelectric conversion layer facing away from the TFT backplane, the common electrode covering the colloidal quantum dot photoelectric conversion layer, and the common electrode and the bias electrode are made of the same material so that the common electrode and the bias electrode are conductively connected through the colloidal quantum dot photoelectric conversion layer.

[0006] In this embodiment, the photoelectric conversion layer is composed of colloidal quantum dots. By controlling the material and size of the quantum dots, the photoelectric conversion layer is capable of sensing short-wave infrared light, which has a wavelength range of 1 to 3 microns. Short-wave infrared imaging combines the characteristics of visible light reflection imaging and long-wave infrared imaging, and has broad application prospects in low-light-level night vision, imaging through haze, food color sorting, semiconductor testing, and other fields. Visible light imaging has the advantages of being able to reveal shadows and contrast, while long-wave infrared imaging includes information about molecular vibrations and thermal properties.

[0007] Multiple bias electrodes are provided on the side of the colloidal quantum dot photoelectric conversion layer facing the TFT backplane, and a common electrode is provided on the side of the colloidal quantum dot photoelectric conversion layer facing away from the TFT backplane. The common electrode covers the sensing area. Each bias electrode corresponds to a pixel, and each pixel includes a thin-film transistor. The common electrode and the bias electrode are electrically connected through the colloidal quantum dot photoelectric conversion layer. When the common electrode and the bias electrode are made of the same material, the colloidal quantum dot photoelectric conversion layer located between the common electrode and the bias electrode acts as a conductor, so the common electrode and the bias electrode can be directly electrically connected to the colloidal quantum dot photoelectric conversion layer. When a bias voltage is applied to the bias electrode, an electric field is formed between the bias electrode and the common electrode. Since each pixel has a bias electrode, each bias electrode corresponds to a thin-film transistor, and the distance between the bias electrode and the common electrode in each pixel is equal. Therefore, the electric field distribution within each pixel is more uniform, which can improve image quality and thus the resolution of the short-wave infrared focal plane sensor.

[0008] The use of colloidal quantum dots to prepare the photoelectric conversion layer in the short-wave infrared focal plane sensor can achieve material synthesis through a single hot injection, and when interconnecting the colloidal quantum dot photoelectric conversion layer with the readout circuit, liquid phase coupling technology can be used. Liquid phase coupling technology includes various methods such as spin coating, spray coating, scraping, and screen printing. Specifically, it refers to applying a colloidal solution containing suspended colloidal quantum dots on the backplane TFT by spin coating, spraying, scraping or screen printing, and covering it on the bias electrode, so that the bias electrode and the common electrode are directly connected through the colloidal quantum dot photoelectric conversion layer. The use of liquid phase coupling technology to achieve the interconnection between the colloidal quantum dot photoelectric conversion layer and the readout circuit can greatly reduce the process difficulty and cost compared to the short-wave infrared focal plane sensor prepared with indium gallium arsenide materials in traditional technology, which is of great significance for opening up a low-cost civilian-grade market for short-wave infrared detectors. This is because the short-wave infrared focal plane sensor made of traditional indium gallium arsenide materials needs to interconnect the detector array with the silicon-based readout circuit through the indium column flip-chip bonding process. The cost of semiconductor epitaxial growth is high, the flip-chip bonding efficiency is low, and the cost is high.

[0009] In addition, the short-wave infrared focal plane sensor according to the embodiment of the present application may also have the following technical features:

[0010] In one embodiment, the short-wave infrared photoelectric conversion material used in the colloidal quantum dot photoelectric conversion layer is HgTe semiconductor quantum dots or PbS semiconductor quantum dots.

[0011] In one embodiment, a pixel electrode is provided on a side of the colloidal quantum dot photoelectric conversion layer facing the TFT backplane, and the colloidal quantum dot photoelectric conversion layer forms a PI junction between the pixel electrode and the common electrode.

[0012] In one embodiment, the bias electrode and the pixel electrode are provided in the same layer, and the bias electrode and the pixel electrode are embedded in the colloidal quantum dot photoelectric conversion layer.

[0013] In one embodiment, the colloidal quantum dot photoelectric conversion layer includes an intrinsic semiconductor layer and a P-type semiconductor layer, so that the colloidal quantum dot photoelectric conversion layer forms a PI junction between the pixel electrode and the common electrode, and the intrinsic semiconductor layer is arranged on a side close to the base substrate.

[0014] In one embodiment, the bias electrode includes a first conductive layer, the pixel electrode includes a second conductive layer, the first conductive layer is one of gold, silver, aluminum, and lithium, and the second conductive layer is indium tin oxide or indium zinc oxide.

[0015] In one embodiment, the bias electrode and the pixel electrode both further include a third conductive layer, and the third conductive layer is respectively arranged on the side of the first conductive layer and the second conductive layer close to the base substrate, and the third conductive layer is a single layer of molybdenum, a single layer of aluminum, or two layers of molybdenum and a layer of aluminum located between the two layers of molybdenum.

[0016] In one embodiment, the thin film transistor includes: a gate and an active layer provided on one side of the substrate, and a source and a drain electrically connected to the active layer; the source and the drain are respectively in contact and electrically connected to the active layer, and the pixel electrode is electrically connected to the source through a via.

[0017] In one embodiment, the TFT backplane further includes a peripheral area surrounding the sensing area, the sensing area of ​​the TFT backplane includes a plurality of bias electrode connection lines, data lines, and scan lines, the data lines and the scan lines are arranged to intersect, the peripheral area includes a bias ring and a COF port, the bias electrode connection line is used to electrically connect a plurality of bias electrodes along the length direction of the substrate, the bias electrode connection line is electrically connected to the bias ring, and the bias ring is electrically connected to the ROIC through the COF port;

[0018] The gate electrodes of the plurality of thin film transistors are electrically connected to the scan lines, and the scan lines are electrically connected to the Gate IC through the COF port; the source electrodes of the plurality of thin film transistors are electrically connected to the data lines, and the data lines are electrically connected to the ROIC through the COF port.

[0019] In one embodiment, a storage capacitor electrode is further provided on the base substrate. The storage capacitor electrode is spaced apart from the gate electrode, and the storage capacitor electrode and the source electrode form a storage capacitor.

[0020] A second aspect of an embodiment of the present application provides a short-wave infrared detector, which includes the short-wave infrared focal plane sensor described above.

[0021] A third aspect of the present application provides a method for manufacturing a shortwave infrared focal plane sensor, which is used to manufacture the shortwave infrared focal plane sensor described above, comprising the following steps:

[0022] Providing the TFT backplane, the TFT backplane comprising a substrate and a gate electrode, an active layer, a source electrode and a drain electrode electrically connected to the active layer, and a planar layer covering the source electrode and the drain electrode, which are sequentially deposited on the substrate;

[0023] Fabricating the bias electrode and the pixel electrode on the flat layer of the TFT backplane, wherein the pixel electrode is connected to the source via hole;

[0024] Depositing a colloidal quantum dot photoelectric conversion layer above the pixel electrode and the bias electrode, wherein the orthographic projection of the colloidal quantum dot photoelectric conversion layer on the TFT backplane covers the sensing area of ​​the TFT backplane;

[0025] The common electrode is deposited above the colloidal quantum dot photoelectric conversion layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other embodiments can also be obtained based on these drawings.

[0027] Figure 1 A schematic structural diagram of a short-wave infrared focal plane sensor provided in an embodiment of the present application;

[0028] Figure 2 A cross-sectional view of a pixel of a short-wave infrared focal plane sensor provided in an embodiment of the present application;

[0029] Figure 3 A 2*2 pixel top view of the shortwave infrared focal plane sensor provided in an embodiment of the present application;

[0030] Figure 4 This is an equivalent circuit diagram of the TFT backplane of a short-wave infrared focal plane sensor provided in an embodiment of the present application.

[0031] The figure numbers are as follows: 10-sensing area; 20-peripheral area; 30-TFT backplane; 31-substrate; 32-active layer; 33-source; 34-drain; 35-gate; 36-storage capacitor electrode; 37-interlayer insulating layer, 38-flat layer; 381-first flat layer; 382-second flat layer; 383-third flat layer; 39-metal trace; 40-colloidal quantum dot photoelectric conversion layer; 41-bias electrode; 411-first conductive layer; 42-pixel electrode; 421-second conductive layer; 43-common electrode; 44-intrinsic semiconductor layer; 45-P-type semiconductor layer; 46-third conductive layer; 50-ROIC; 60-Gate IC; 70-COF port; 80-first port; 90-second port; P-bias ring; P1-bias electrode connecting line; D-data line; G-scan line. DETAILED DESCRIPTION

[0032] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field based on this application are within the scope of protection of the present invention.

[0033] A first aspect of the present application provides a short-wave infrared focal plane sensor, such as Figure 1 As shown, the short-wave infrared focal plane sensor includes a sensing area 10 and a peripheral area 20. The peripheral area 20 is electrically connected to a Gate IC (driver IC) 60 and a ROIC (Read Out IC) 50, which control the operation of the sensing area 10, via a COF port 70. A first port 80 is provided at the other end of the ROIC 50 for electrically connecting to a driver and reader circuit board. The circuit board can be electrically connected to a reader device via a USB interface. A second port 90 is provided at the other end of the Gate IC 60 for electrically connecting to the circuit board. The first port 80 and the second port 90 can be connected to the same circuit board.

[0034] Specifically, if Figure 2 As shown, it includes a TFT (Thin Film Transistor) backplane 30 and a colloidal quantum dot photoelectric conversion layer 40 provided on the TFT backplane 30. The orthographic projection of the colloidal quantum dot photoelectric conversion layer 40 on the TFT backplane 30 covers the sensing area 10 of the TFT backplane 30. The colloidal quantum dot photoelectric conversion layer 40 is used to sense short-wave infrared light. The TFT backplane 30 includes a base substrate 31 and a thin film transistor layer provided in the sensing area 10 of the base substrate 31; the thin film transistor layer is provided between the base substrate 31 and the colloidal quantum dot photoelectric conversion layer 40, and the thin film transistor layer includes a plurality of thin film transistors, each thin film transistor corresponding to one pixel. Figure 3 As shown, a plurality of bias electrodes 41 are provided on the side of the colloidal quantum dot photoelectric conversion layer 40 facing the TFT backplane 30, and each bias electrode 41 corresponds to a thin film transistor; a common electrode 43 is provided on the side of the colloidal quantum dot photoelectric conversion layer 40 facing away from the TFT backplane 30, and the common electrode 43 covers the sensing area 10 of the colloidal quantum dot photoelectric conversion layer 40 in the positive projection on the TFT backplane 30. The common electrode 43 and the bias electrode 41 are made of the same material so that the common electrode 43 and the bias electrode 41 are conductively connected through the colloidal quantum dot photoelectric conversion layer 40.

[0035] In this embodiment, colloidal quantum dot photoelectric conversion layer 40 is uniformly dispersed with colloidal quantum dots. By regulating the material and size of the colloidal quantum dots, colloidal quantum dot photoelectric conversion layer 40 is capable of sensing short-wave infrared light, which has a wavelength range of 1 to 3 microns. Short-wave infrared imaging combines the characteristics of visible light reflection imaging and long-wave infrared imaging, and has broad application prospects in low-light-level night vision, imaging through haze, food color sorting, semiconductor testing, and other fields. Visible light imaging has the characteristics of being able to display shadows and contrast of objects, while long-wave infrared imaging has the characteristics of containing molecular vibration information and object thermal information.

[0036] like Figure 2 As shown, a plurality of bias electrodes 41 are provided on the side of the colloidal quantum dot photoelectric conversion layer 40 facing the TFT back plate 30, and a common electrode 43 is provided on the side of the colloidal quantum dot photoelectric conversion layer 40 facing away from the TFT back plate 30. The common electrode 43 covers the sensing area 10. Figure 3 As shown, each bias electrode 41 corresponds to a pixel, each pixel includes a thin film transistor, and the common electrode 43 and the bias electrode 41 are connected through the colloidal quantum dot photoelectric conversion layer 40. When the common electrode 43 and the bias electrode 41 are made of the same material, the colloidal quantum dot photoelectric conversion layer 40 located between the common electrode 43 and the bias electrode 41 is equivalent to a conductor, so the common electrode 43 and the bias electrode 41 can be directly connected to the colloidal quantum dot photoelectric conversion layer 40. When a bias voltage is applied to the bias electrode 41, an electric field is formed between the bias electrode 41 and the common electrode 43. Since each pixel is provided with a bias electrode 41, each bias electrode 41 corresponds to a thin film transistor, and the distance between the bias electrode 41 and the common electrode 43 in each pixel is equal. Therefore, the electric field distribution in each pixel will be more uniform, which can improve the image quality and thus improve the resolution of the short-wave infrared focal plane sensor.

[0037] The use of colloidal quantum dots to prepare the photoelectric conversion layer in the short-wave infrared focal plane sensor can achieve material synthesis through a single hot injection, and when interconnecting the colloidal quantum dot photoelectric conversion layer 40 with the readout circuit, liquid phase coupling technology can be used. Liquid phase coupling technology includes various methods such as spin coating, spray coating, scraping, and screen printing. Specifically, it refers to applying a colloidal solution containing suspended colloidal quantum dots to the backplane TFT by spin coating, spraying, scraping, or screen printing, and covering the bias electrode 41, so that the bias electrode 41 and the common electrode 43 are directly connected through the colloidal quantum dot photoelectric conversion layer 40. The use of liquid phase coupling technology to achieve the interconnection between the colloidal quantum dot photoelectric conversion layer 40 and the readout circuit can greatly reduce the process difficulty and cost compared to the short-wave infrared focal plane sensor prepared with indium gallium arsenide materials in traditional technology, which is of great significance for opening up a low-cost civilian market for short-wave infrared detectors. This is because the short-wave infrared focal plane sensor made of traditional indium gallium arsenide materials needs to interconnect the detector array with the silicon-based readout circuit through the indium column flip-chip bonding process. The cost of semiconductor epitaxial growth is high, the flip-chip bonding efficiency is low, and the cost is high.

[0038] Specifically, the short-wave infrared photoelectric conversion material used in the colloidal quantum dot photoelectric conversion layer 40 is HgTe (mercury telluride) or PbS (lead sulfide) semiconductor material.

[0039] The colloidal quantum dot photoelectric conversion layer 40 made of HgTe or PbS semiconductor materials is suitable for absorbing visible light and short-wave infrared light, and can therefore improve the conversion efficiency of the colloidal quantum dot photoelectric conversion layer 40 for visible light and short-wave infrared light, stimulate the colloidal quantum dot photoelectric conversion layer 40 to generate more photogenerated carriers, and increase the current intensity formed by the directional movement of photogenerated carriers, thereby increasing the intensity of the electrical signal of the short-wave infrared focal plane sensor and improving the resolution of the short-wave infrared focal plane sensor.

[0040] More specifically, if Figure 2 As shown, a pixel electrode 42 is provided on the side of the colloidal quantum dot photoelectric conversion layer 40 facing the TFT backplane 30 , and a PI (Positive-Intrinsic) junction is formed between the pixel electrode 42 and the common electrode 43 .

[0041] In this embodiment, the pixel electrode 42 is disposed on the side of the colloidal quantum dot photoelectric conversion layer 40 facing the TFT backplane 30, such that the pixel electrode 42 and the common electrode 43 are located on either side of the colloidal quantum dot photoelectric conversion layer 40. Because the pixel electrode 42 and the common electrode 43 are made of different materials, the colloidal quantum dot photoelectric conversion layer 40 located between them functions as a PI junction. A PI junction functions similarly to a PN junction, exhibiting unidirectional conductivity, except that the semiconductors at both ends differ from those of a PN junction: one end is an intrinsic semiconductor, and the other is a P-type semiconductor. When light passes through the common electrode 43 and irradiates the colloidal quantum dot photoelectric conversion layer 40, the colloidal quantum dot photoelectric conversion layer 40 generates photogenerated carriers. These carriers, under the influence of the electric field formed between the bias electrode 41 and the common electrode 43, form a directional current. When the directional current meets certain conditions, the thin-film transistor turns on, transmitting the current signal through the drain electrode 34 of the thin-film transistor to the imaging device.

[0042] In one embodiment, if Figure 2 As shown, the bias electrode 41 and the pixel electrode 42 are provided in the same layer, and the bias electrode 41 and the pixel electrode 42 are embedded in the colloidal quantum dot photoelectric conversion layer 40 .

[0043] In this embodiment, the bias electrode 41 and pixel electrode 42 are arranged on the same layer, eliminating the need for an interlayer insulating layer 37 and simplifying the fabrication process of the short-wave infrared focal plane sensor. Furthermore, the bias electrode 41 and pixel electrode 42 are embedded within the colloidal quantum dot photoelectric conversion layer 40. This facilitates fabrication of the short-wave infrared focal plane sensor, allowing the colloidal quantum dot photoelectric conversion layer 40 to be deposited directly on the bias electrode 41 and pixel electrode 42, eliminating the need to fill the gap between the bias electrode 41 and pixel electrode 42.

[0044] In one embodiment, if Figure 2 As shown, the colloidal quantum dot photoelectric conversion layer 40 includes an intrinsic semiconductor layer 44 and a P-type semiconductor layer 45, so that the colloidal quantum dot photoelectric conversion layer 40 forms a PI junction between the pixel electrode 42 and the common electrode 43, and the intrinsic semiconductor layer 44 is arranged on the side close to the base substrate 31.

[0045] In this embodiment, there are two equal numbers of carriers in the intrinsic semiconductor layer 44, namely, the number of free electrons and holes is equal. A P-type semiconductor refers to a semiconductor in which the number of holes is far greater than the number of free electrons. The intrinsic semiconductor layer 44 is arranged close to the base substrate 31. When light is irradiated to the colloidal quantum dot photoelectric conversion layer 40 through the common electrode 43, the free electrons in the intrinsic semiconductor are excited, thereby spontaneously moving to the P-type semiconductor and occupying the vacancies in the P-type semiconductor. The free electrons move from the intrinsic semiconductor layer 44 to the P-type semiconductor layer 45, forming a current from the P-type semiconductor to the intrinsic semiconductor layer 44, thereby turning on the thin film transistor and transmitting the current signal.

[0046] In one embodiment, if Figure 2 As shown, the bias electrode 41 includes a first conductive layer 411 , and the pixel electrode 42 includes a second conductive layer 421 . The first conductive layer 411 is gold, and the second conductive layer 421 is indium tin oxide (ITO) or indium zinc oxide (IZO).

[0047] In this embodiment, both bias electrode 41 and pixel electrode 42 are formed from a conductive layer. Gold and either indium tin oxide or indium zinc oxide are materials with high work functions, which can improve the hole injection rate. Furthermore, indium tin oxide or indium zinc oxide have strong water and oxygen resistance, while gold is chemically stable and not easily oxidized by air, thereby extending the service life of the short-wave infrared focal plane sensor.

[0048] Furthermore, if Figure 2 As shown, the bias electrode 41 and the pixel electrode 42 also include a third conductive layer 46, which is respectively arranged on the side of the first conductive layer 411 and the second conductive layer 421 close to the base substrate 31. The third conductive layer 46 is a single layer of molybdenum, a single layer of aluminum, or two layers of molybdenum and a layer of aluminum located between the two layers of molybdenum.

[0049] In this embodiment, a third conductive layer 46 is provided below the second conductive layer 421. The third conductive layer 46 comprises a single layer of molybdenum, a single layer of aluminum, or two layers of molybdenum and a layer of aluminum between the two layers of molybdenum. This can reduce the square resistance of the second conductive layer 421, facilitate charge transfer, reduce current loss, and thus improve the sensitivity of the short-wave infrared focal plane sensor.

[0050] At the same time, a third conductive layer 46 is also provided below the first conductive layer 411. The third conductive layer 46 of the bias electrode 41 and the third conductive layer 46 of the pixel electrode 42 can be provided on the same layer. There is no need to etch the third conductive layer 46 below the first conductive layer 411. The first conductive layer 411 and the second conductive layer 421 can be directly deposited above the third conductive layer 46, making the manufacturing process of the bias electrode 41 and the pixel electrode 42 simpler.

[0051] Specifically, if Figure 2 As shown, in one embodiment, the thin film transistor includes a gate 35 and an active layer 32 provided on one side of a substrate 31, as well as a source electrode 33 and a drain electrode 34 electrically connected to the active layer 32. The source electrode 33 and the drain electrode 34 are respectively in contact and electrically connected to the active layer 32, and the pixel electrode 42 is electrically connected to the source electrode 33 via a via.

[0052] In this embodiment, the source electrode 33 and the drain electrode 34 are respectively electrically connected to the active layer 32, which can simplify the thin-film transistor manufacturing process. The pixel electrode 42 is connected to the source electrode 33 through a via, which allows for flexible selection of the pixel electrode 42's location and size. Specifically, the via is provided in a planar layer 38 located above the source electrode 33. The planar layer 38 serves both as a planarizer and an insulator, and can comprise multiple layers. In one feasible embodiment, the planar layer 38 includes a first planar layer 381, a second planar layer 382, ​​and a third planar layer 383, which are sequentially arranged in a direction away from the substrate 31. The first planar layer 381 and the third planar layer 383 can be silicon nitride (SiNx) layers, and the second planar layer 382 can be a resin layer. The pixel electrode 42 is connected to the source electrode 33 through a via with a depth of approximately 2.1 microns. To reduce the size of the pixel electrode 42, a metal trace 39 can be provided between the pixel electrode 42 and the source electrode 33, electrically connecting the two. In addition, an interlayer insulating layer 37 is provided between the active layer 32 and the gate 35 to isolate the active layer 32 from the gate 35 .

[0053] In one embodiment, if Figure 4 As shown, the TFT backplane 30 also includes a peripheral region 20 surrounding the sensing region 10. The sensing region 10 of the TFT backplane 30 includes multiple bias electrode connection lines P1, data lines D, and scan lines G, which are arranged at an intersection. The peripheral region 20 includes a bias ring P and a COF port. The bias electrode connection line P1 is used to electrically connect multiple bias electrodes 41 along the length of the substrate 31. The bias electrode connection line P1 is electrically connected to the bias ring P. The bias ring P is electrically connected to one end of the ROIC 50 via the COF port 70. The other end of the ROIC is electrically connected to the drive readout circuit board via a first port 80. The gate electrodes 35 of the multiple thin-film transistors are electrically connected to the scan lines G. The scan lines G are electrically connected to one end of the gate IC 60 via the COF port 70. The other end of the gate IC 60 is electrically connected to the circuit board via a second port 90. The source electrodes 33 of the multiple thin-film transistors are electrically connected to the data lines D, and the data lines D are electrically connected to the ROIC 50 via the COF port 70.

[0054] In this embodiment, the ROIC 50 applies a bias voltage to each bias electrode 41 through the bias ring P via the bias electrode connection line P1, forming a stable electric field between the bias electrode 41 and the common electrode 43. The Gate IC 60 applies a signal to the gate 35 to indicate whether the thin film transistor is on or off via the scan line G. Only when the thin film transistor is on can the current induced by the colloidal quantum dot photoelectric sensing layer pass through the pixel electrode 42 and flow to the source 33 through the data line D electrically connected to the pixel electrode 42, and then flow through the active layer 32 to the drain 34. The current is output through the drain 34 and converted into recognizable image information, which is fed back to the reading device. The multiple bias electrode connection lines P1 of the sensing area 10 are used to electrically connect the multiple bias electrodes 41 along the length direction of the substrate 31, such as Figure 4 As shown, multiple bias electrodes 41 are electrically connected along the row direction and are electrically connected to the bias ring P provided in the peripheral area 20. Therefore, the driving signal can be sent to each bias electrode 41 by simply electrically connecting the bias ring P to the ROIC 50. The data line D and the scan line G are arranged to intersect, as shown in FIG. Figure 4 As shown, the scan lines G are arranged along the row direction, and the data lines D are arranged along the column direction, and the two are perpendicular to each other, of course, they can also be non-perpendicular. One end of the ROIC 50 and the Gate IC 60 are electrically connected to the bias ring P, data lines D, and scan lines G of the peripheral area 20 through the COF port 70. In addition to having a connection function, the COF port 70 can also carry active and passive components, making the product lighter and thinner. Figure 4 As shown, there may be multiple ROICs 50 , for example, there may be two ROICs 50 , and the other ends of the ROICs 50 are electrically connected to the reading device through the first ports 80 .

[0055] In one embodiment, if Figure 2 As shown, a storage capacitor electrode 36 is further provided on the base substrate 31 . The storage capacitor electrode 36 is spaced apart from the gate 35 . The storage capacitor electrode 36 and the source 33 form a storage capacitor.

[0056] In this embodiment, the provision of the storage capacitor electrode 36 enables the thin film transistor to temporarily store excess charge, thereby reducing charge loss and increasing the intensity of the output current.

[0057] A second aspect of an embodiment of the present application provides a short-wave infrared detector, comprising the short-wave infrared focal plane sensor described above.

[0058] The short-wave infrared detector in the embodiment of the present application includes a short-wave infrared focal plane sensor, which includes a TFT backplane 30 and a colloidal quantum dot photoelectric conversion layer 40 arranged on the TFT backplane 30. Each thin-film transistor in the TFT backplane 30 corresponds to a pixel, and a bias electrode 41 is provided in each pixel. When a bias voltage is applied to the bias electrode 41, an electric field is formed between the bias electrode 41 and the common electrode 43. Since a bias electrode 41 is provided in each pixel, each bias electrode 41 corresponds to a thin-film transistor, and the distance between the bias electrode 41 and the common electrode 43 in each pixel is equal, the electric field distribution in each pixel will be more uniform, which can improve the image acquisition quality, thereby improving the resolution of the short-wave infrared focal plane sensor.

[0059] A third aspect of the present application provides a method for manufacturing a short-wave infrared focal plane sensor, comprising the following steps:

[0060] S1: Provide a TFT backplane 30 , which includes a substrate and a gate 35 , an active layer 32 , a source electrode 33 and a drain electrode 34 electrically connected to the active layer 32 , and a planar layer 38 covering the source electrode 33 and the drain electrode 34 , which are sequentially deposited on a substrate 31 .

[0061] S2: A bias electrode 41 and a pixel electrode 42 are fabricated on the planar layer 38 of the TFT backplane 30 . The pixel electrode 42 is connected to the source electrode 33 through a via hole.

[0062] S3 : depositing a colloidal quantum dot photoelectric conversion layer 40 on the pixel electrode 42 and the bias electrode 41 . The orthographic projection of the colloidal quantum dot photoelectric conversion layer 40 on the TFT backplane 30 covers the sensing area 10 of the TFT backplane 30 .

[0063] S4 : depositing a common electrode 43 on the colloidal quantum dot photoelectric conversion layer 40 .

[0064] In this embodiment, a planarization layer 38 is deposited between the bias electrode 41, the pixel electrode 42, and the source 33 and drain 34 of the TFT backplane 30. This planarization layer 38 is an insulating material that separates the bias electrode 41 from the pixel electrode 42 and the source 33 and drain 34, ensuring independent operation of each electrode. The colloidal quantum dot photoelectric conversion layer 40 above the pixel electrode 42 and bias electrode 41 senses short-wave infrared light and converts the optical signal into an electrical signal, which is then applied to the pixel electrode 42. This voltage is then output to the source 33 of the thin-film transistor, controlling the thin-film transistor to turn on and feed the electrical signal back to a reader, which then presents a recognizable image based on the feedback information.

[0065] The planar layer 38 may include multiple layers made of different materials, such as a resin layer and a silicon nitride layer.

[0066] Furthermore, the colloidal quantum dots in the colloidal quantum dot photoelectric conversion layer 40 can be made of HgTe or PbS semiconductor materials that have good absorption effects on visible light and short-wave infrared light. The colloidal quantum dot photoelectric conversion layer 40 includes an intrinsic semiconductor layer 44 and a P-type semiconductor layer 45 .

[0067] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply the existence of any such actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article, or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or device. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, method, article, or device comprising the element.

[0068] Each embodiment in this specification is described in a related manner. Similar parts between the various embodiments can be referred to in conjunction with each other. Each embodiment focuses on the differences between the other embodiments. In particular, the system embodiment is generally similar to the method embodiment, so the description is relatively simple. For related parts, refer to the description of the method embodiment.

[0069] The above description is only a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention are included in the scope of protection of the present invention.

Claims

1. A short-wave infrared focal plane sensor, characterized in that: It includes a TFT backplane and a colloidal quantum dot photoelectric conversion layer provided on the TFT backplane, wherein the orthographic projection of the colloidal quantum dot photoelectric conversion layer on the TFT backplane covers the sensing area of ​​the TFT backplane, and the colloidal quantum dot photoelectric conversion layer is used to sense short-wave infrared light; The TFT backplane includes a base substrate and a thin film transistor layer disposed in a sensing area of ​​the base substrate; the thin film transistor layer is disposed between the base substrate and the colloidal quantum dot photoelectric conversion layer, and the thin film transistor layer includes a plurality of thin film transistors, each thin film transistor corresponding to a pixel; The colloidal quantum dot photoelectric conversion layer is provided with multiple bias electrodes on the side facing the TFT backplane, and each bias electrode corresponds to one of the thin film transistors; the colloidal quantum dot photoelectric conversion layer is provided with a common electrode on the side facing away from the TFT backplane, and the common electrode covers the colloidal quantum dot photoelectric conversion layer. The common electrode and the bias electrode are made of the same material so that the common electrode and the bias electrode are conductive through the colloidal quantum dot photoelectric conversion layer.

2. The shortwave infrared focal plane sensor according to claim 1, characterized in that The short-wave infrared photoelectric conversion material used in the colloidal quantum dot photoelectric conversion layer is HgTe semiconductor quantum dots or PbS semiconductor quantum dots.

3. The shortwave infrared focal plane sensor according to claim 1, characterized in that: A pixel electrode is provided on a side of the colloidal quantum dot photoelectric conversion layer facing the TFT backplane, and a PI junction is formed between the colloidal quantum dot photoelectric conversion layer and the common electrode.

4. The shortwave infrared focal plane sensor according to claim 3, characterized in that: The bias electrode and the pixel electrode are arranged in the same layer, and the bias electrode and the pixel electrode are embedded in the colloidal quantum dot photoelectric conversion layer.

5. The shortwave infrared focal plane sensor according to claim 3, characterized in that: The colloidal quantum dot photoelectric conversion layer includes an intrinsic semiconductor layer and a P-type semiconductor layer, so that the colloidal quantum dot photoelectric conversion layer forms a PI junction between the pixel electrode and the common electrode, and the intrinsic semiconductor layer is arranged on a side close to the base substrate.

6. The shortwave infrared focal plane sensor according to claim 3, characterized in that: The bias electrode includes a first conductive layer, and the pixel electrode includes a second conductive layer. The first conductive layer is one of gold, silver, aluminum, and lithium, and the second conductive layer is indium tin oxide or indium zinc oxide.

7. The shortwave infrared focal plane sensor according to claim 6, characterized in that: The bias electrode and the pixel electrode both further include a third conductive layer, which is respectively arranged on the side of the first conductive layer and the second conductive layer close to the base substrate, and the third conductive layer is a single layer of molybdenum, a single layer of aluminum, or two layers of molybdenum and a layer of aluminum located between the two layers of molybdenum.

8. The shortwave infrared focal plane sensor according to any one of claims 3 to 7, characterized in that: The thin film transistor includes: a gate and an active layer provided on one side of a base substrate, and a source and a drain electrically connected to the active layer; the source and the drain are respectively in contact and electrically connected to the active layer, and the pixel electrode is electrically connected to the source through a via hole.

9. The shortwave infrared focal plane sensor according to any one of claims 1 to 7, characterized in that: The TFT backplane further includes a peripheral area surrounding the sensing area, the sensing area of ​​the TFT backplane includes a plurality of bias electrode connection lines, data lines, and scan lines, the data lines and the scan lines being arranged to intersect, the peripheral area includes a bias ring and a COF port, the bias electrode connection line is used to electrically connect a plurality of bias electrodes along the length direction of the substrate, the bias electrode connection line is electrically connected to the bias ring, and the bias ring is electrically connected to the ROIC through the COF port; The gate electrodes of the plurality of thin film transistors are electrically connected to the scan lines, and the scan lines are electrically connected to the Gate IC through the COF port; the source electrodes of the plurality of thin film transistors are electrically connected to the data lines, and the data lines are electrically connected to the ROIC through the COF port.

10. The shortwave infrared focal plane sensor according to claim 8, characterized in that: A storage capacitor electrode is further provided on the base substrate. The storage capacitor electrode is spaced apart from the gate electrode, and the storage capacitor electrode and the source electrode form a storage capacitor.

11. A short-wave infrared detector, characterized in that: The shortwave infrared detector comprises the shortwave infrared focal plane sensor according to any one of claims 1 to 10.

12. A method for manufacturing a shortwave infrared focal plane sensor, for manufacturing the shortwave infrared focal plane sensor according to any one of claims 1 to 10, characterized in that: The following steps are involved: Providing the TFT backplane, the TFT backplane comprising a base substrate and a gate electrode, an active layer, a source electrode and a drain electrode electrically connected to the active layer, and a planar layer covering the source electrode and the drain electrode, which are sequentially deposited on the base substrate; Fabricating the bias electrode and the pixel electrode on the flat layer of the TFT backplane, wherein the pixel electrode is connected to the source electrode through a via hole; Depositing a colloidal quantum dot photoelectric conversion layer above the pixel electrode and the bias electrode, wherein the orthographic projection of the colloidal quantum dot photoelectric conversion layer on the TFT backplane covers the sensing area of ​​the TFT backplane; The common electrode is deposited above the colloidal quantum dot photoelectric conversion layer.

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