Gradient band gap photodiode detector, preparation method thereof and reconstruction spectrometer

Abstract

The invention relates to the technical field of photoelectric detection, and discloses a gradient band gap photodiode detector, a preparation method thereof and a reconstruction spectrometer. The preparation method comprises the steps of providing a substrate; forming a conductive layer on the surface of one side of the substrate; forming a first carrier transport layer on the substrate; forming an initial semiconductor photosensitive layer on the first carrier transport layer; immersing the substrate into the reaction solution along a first preset direction; pulling out the substrate from the reaction solution to form a gradient band gap semiconductor photosensitive layer; forming a second carrier transport layer on the gradient band gap semiconductor photosensitive layer; and forming a plurality of first electrode structures arranged in an array on the second carrier transport layer, and forming a second electrode structure connected with the conductive layer on the substrate. The gradient band gap semiconductor photosensitive layer and the first electrode structure of the array form a photodiode array photoelectric detector array, different spectral responses and wide dynamic response ranges are achieved, and the linear solution accuracy and spectral resolution of a spectrum reconstruction algorithm are improved.

Description

Technical Field

[0001] The invention relates to the field of photoelectric detection technology, and in particular to a gradient bandgap photodiode detector and a preparation method thereof, and a reconstruction spectrometer. Background Art

[0002] Spectrometers are widely used in healthcare, food safety monitoring, portable or wearable sensor devices, drone remote sensing and space exploration. Traditional spectrometers use interferometers, gratings, prisms and mechanical systems to analyze spectra. The spectrometer equipment has a complex structure and is large in size. Based on this, the use of photodetector arrays with different band gaps combined with a spectrum reconstruction algorithm has become an effective strategy to achieve the miniaturization and integration of spectrometers. Semiconductor materials with different band gaps, such as perovskite, cadmium selenide sulfide, and indium gallium nitride, have begun to be used to prepare the photosensitive layer of photodetectors to form photodetectors with different band gaps. Photodetectors with different band gaps have specific light response spectra for specific wavelengths of light. Combined with the measured response current of the unknown incident spectrum, the spectrum reconstruction algorithm is used to solve the equations to reconstruct the spectrum of the light to be measured.

[0003] However, photodetectors are divided into basic types such as photomultiplier tubes, photoconductors, and photodiodes. In the related technology, there is a gradient bandgap CdS that will be used to prepare photoresistors. x Se 1-x Nanowires are used as reconstruction spectrometers, or gradient bandgap three-dimensional halide perovskite MAPbX3 (X=Cl, Br, I) nanowires are used as reconstruction spectrometers. However, in the above two schemes, the photodetector type is photoconductive, and the spectrometer reconstruction algorithm can only make a linear approximation solution to the equations obtained by the photoconductive photodetector, which greatly affects the accuracy of the reconstructed spectrum and limits the resolution of the miniature spectrometer with photodetector. Summary of the invention

[0004] In view of this, the present invention provides a gradient bandgap photodiode detector and a preparation method thereof, and a reconstruction spectrometer to solve the problems of low resolution and accuracy of existing spectrometers.

[0005] In a first aspect, the present invention provides a method for preparing a gradient bandgap photodiode detector, comprising:

[0006] providing a substrate;

[0007] forming a conductive layer on one surface of the substrate;

[0008] Forming a first carrier transport layer on a surface of the substrate having a conductive layer;

[0009] Forming an initial semiconductor photosensitive layer on a surface of the first carrier transport layer facing away from the substrate;

[0010] The substrate having the conductive layer, the first carrier transport layer and the initial semiconductor photosensitive layer is gradually immersed in the reaction solution from the first end of the substrate along a first preset direction;

[0011] Pulling the substrate out of the reaction solution along a first preset direction from a first end of the substrate toward a second end opposite to the first end, so as to form a gradient bandgap semiconductor photosensitive layer with a gradually changing bandgap along the first preset direction;

[0012] Forming a second carrier transport layer on a surface of the gradient bandgap semiconductor photosensitive layer that is away from the substrate;

[0013] A plurality of first electrode structures are formed on a surface of the second carrier transport layer facing away from the substrate, and a second electrode structure is formed on the substrate; the plurality of first electrode structures are arranged in an array, and the second electrode structure is connected to the conductive layer.

[0014] Beneficial effects: The preparation method of the gradient bandgap photodiode detector of the present invention forms a gradient bandgap semiconductor photosensitive layer, that is, a gradient bandgap perovskite layer, by exchanging halogen ions in a solution, and forms a first carrier transport layer and a second carrier transport layer, that is, an electron transport layer and a hole transport layer, on the upper and lower sides of the gradient bandgap semiconductor photosensitive layer by a method such as spin coating, thereby forming a PIN-type or NIP-type photodiode structure, and then a plurality of first electrode structures arranged in an array are provided to finally form a photodiode-type photodetector with a gradient bandgap, which converts a light signal incident from the substrate direction into an electrical signal, and improves the extraction of photogenerated carriers on the basis of ensuring that the gradient bandgap semiconductor photosensitive layer has different spectral responses, so that the photodetector has a wide dynamic response range and a fast response speed, and the gradient bandgap semiconductor photosensitive layer and the array-arranged first electrode structure constitute a photodiode array photodetector array, which is conducive to the accuracy of the linear solution of the spectral reconstruction algorithm, and has the characteristics of high spectral resolution, simple process and easy integration.

[0015] In an optional embodiment, the material of the substrate includes any one or more of glass, quartz, sapphire, polyethylene naphthalate, polyimide, polyvinylidene fluoride, polyetherimide, and polyethylene terephthalate plastics. The selection of different substrate materials helps to improve the applicability of the gradient bandgap photodiode detector.

[0016] In an optional embodiment, the conductive layer is located on a portion of the surface of one side of the substrate; the first carrier transport layer covers a portion of the substrate to expose a portion of the substrate and a portion of the conductive layer, and the second electrode structure is disposed on the exposed substrate to be connected to the conductive layer.

[0017] Beneficial effect: In vertically stacked devices, the current density is calculated by dividing the measured current value by the effective area of ​​the device, i.e., the coupling area between the first electrode structure and the second electrode structure and the conductive layer. Using a partially deposited conductive layer can more accurately control the size of the device's effective area than depositing the conductive layer on the entire surface, thereby improving the accuracy of the reconstructed spectrum.

[0018] In an optional embodiment, in the formation of an initial semiconductor photosensitive layer on the surface of the first carrier transport layer facing away from the substrate, the material of the initial semiconductor photosensitive layer includes any one of iodine lead methylamine, other metal halide perovskites, cadmium selenide sulfide, indium gallium nitride, silicon germanium alloy, and organic semiconductors; the method for forming the initial semiconductor photosensitive layer includes any one or more of spin coating, spraying, slit coating, inkjet printing, thermal evaporation, and metal organic chemical vapor deposition.

[0019] Beneficial effects: The initial semiconductor photosensitive layer includes a variety of materials and has a variety of formation methods, providing a variety of possible applications for the initial semiconductor photosensitive layer. For example, the initial semiconductor photosensitive layer of iodine lead methylamine is formed by spin coating and annealing, which provides a basis for the subsequent formation of a gradient band gap semiconductor photosensitive layer by halogen ion exchange.

[0020] In an optional embodiment, the substrate having the conductive layer, the first carrier transport layer and the initial semiconductor photosensitive layer is gradually immersed in the reaction solution from the first end of the substrate along a first preset direction, comprising:

[0021] Fixing the side of the second end of the substrate where the initial semiconductor photosensitive layer is not provided to the clamping assembly;

[0022] The substrate is gradually immersed in the reaction solution from a first end opposite to the second end along a first preset direction until a section of the initial semiconductor photosensitive layer close to the second end is at a preset distance from the surface of the reaction solution.

[0023] Beneficial effect: By rotating the substrate having a conductive layer, a first carrier transport layer and an initial semiconductor photosensitive layer, the initial semiconductor photosensitive layer forms band gap regions with different component ranges on the plane, and using a clamping component with scale markings to perform position changes within a height range helps to achieve precise gradient range control, thereby ensuring the accuracy of the linear solution of the spectral reconstruction algorithm.

[0024] In an alternative embodiment, the reaction solution comprises an isopropanol solution with methylammonium bromide.

[0025] Beneficial effect: The initial semiconductor photosensitive layer of iodine lead methylamine is exchanged with methylammonium bromide for halogen ions in an isopropanol solution to form a gradient bandgap semiconductor photosensitive layer that gradually transitions from iodine lead methylamine to bromide lead methylamine, so that the photodiode-type photodetector has different light response ranges and forms a linearly changing dynamic range, providing conditions for obtaining different responsiveness in the spectrometer, thereby improving the accuracy of the linear solution of the spectrum reconstruction algorithm.

[0026] In an optional implementation, the preset distance is 0.75 mm.

[0027] Beneficial effect: A region of the initial semiconductor photosensitive layer having a length of 0.75 mm is retained and not immersed in the isopropanol solution containing methylammonium bromide, and the range of the retained region is precisely controlled to ensure that the initial semiconductor photosensitive layer has a partial region that is completely iodine lead methylamine.

[0028] In an optional implementation, the width of the first electrode structure is 0.5 mm, the width of the second electrode structure is 0.5 mm; the spacing between adjacent first electrode structures is 0.5 mm, and the number of first electrode structures is a multiple of 12.

[0029] Beneficial effects: The width of the first electrode structure and the second electrode structure are both reasonably set to 0.5 mm, and the spacing between adjacent first electrode structures is also set to 0.5 mm, which helps to control the size of the coupling area between the first electrode structure and the second electrode structure and the conductive layer. The bottom conductive layer and the first electrode structure and the second electrode structure on the top are separated, which is simple in process. Under the premise of ensuring the independent operation of the gradient bandgap photodiode, the number of electrode structures is reduced, which is convenient for measurement. The rational design of the area and spacing of the first electrode structure and the second electrode structure helps to reduce the size of the photodetector and the spectrometer.

[0030] In an optional embodiment, after forming a conductive layer on one side surface of the substrate and before forming a first carrier transport layer on the side surface of the substrate having the conductive layer, the method further includes: performing a first cleaning treatment on the substrate having the conductive layer; and drying the substrate after the first cleaning treatment;

[0031] After forming the gradient bandgap semiconductor photosensitive layer and before forming a second carrier transport layer on the surface of the gradient bandgap semiconductor photosensitive layer facing away from the substrate, it also includes: performing a second cleaning treatment on the substrate with the gradient bandgap semiconductor photosensitive layer; and drying the substrate after the second cleaning treatment.

[0032] Beneficial effects: The substrate with the conductive layer is cleaned with a variety of cleaning solutions and blown dry with nitrogen, which helps to form a clean first carrier transport layer and ensure effective collection and transportation of carriers; after the gradient bandgap semiconductor photosensitive layer is formed, a second cleaning treatment and drying are performed to remove residual reaction solution, forming a stable gradient bandgap semiconductor photosensitive layer, which also helps to form the subsequent second carrier transport layer.

[0033] In the second aspect, the present invention also provides a gradient bandgap photodiode detector, which is manufactured by the above-mentioned preparation method of the gradient bandgap photodiode detector, including: a substrate, a conductive layer, a first carrier transport layer, a gradient bandgap semiconductor photosensitive layer, a second carrier transport layer, a plurality of first electrode structures and a second electrode structure, the conductive layer is arranged on one side surface of the substrate; the first carrier transport layer is arranged on the side surface of the substrate having the conductive layer; the gradient bandgap semiconductor photosensitive layer is arranged on the side surface of the first carrier transport layer away from the substrate, and the bandgap of the gradient bandgap semiconductor photosensitive layer gradually changes along a first preset direction; the second carrier transport layer is arranged on the side surface of the gradient bandgap semiconductor photosensitive layer away from the substrate; a plurality of first electrode structures are arranged on the side surface of the second carrier transport layer away from the substrate, and the plurality of first electrode structures are arranged in an array; the second electrode structure is arranged on the substrate and connected to the conductive layer.

[0034] Beneficial effects: The gradient bandgap photodiode detector of the present invention has a first carrier transport layer and a second carrier transport layer, that is, an electron transport layer and a hole transport layer, arranged on the upper and lower sides of the gradient bandgap semiconductor photosensitive layer, thereby forming a PIN-type or NIP-type photodiode structure. Then, the PIN-type or NIP-type photodiode structure and a plurality of first electrode structures arranged in an array constitute a photodiode array photodetector with a gradient bandgap, which converts light signals incident from the substrate direction into electrical signals. On the basis of ensuring that the gradient bandgap semiconductor photosensitive layer has different spectral responses, the extraction of photogenerated carriers is improved, so that the photodetector has a wide and linearly changing dynamic response range and a fast response speed, which is conducive to the accuracy of the linear solution of the spectral reconstruction algorithm, and has the characteristics of high spectral resolution, simple process and easy integration.

[0035] In the third aspect, the present invention also provides a gradient bandgap photodiode reconstruction spectrometer, comprising: the above-mentioned gradient bandgap photodiode detector, a data selection and current source table module, an initial calibration module and a reconstruction spectrum module, one end of the data selection and current source table module is respectively connected to multiple first electrode structures, and the other end is connected to the second electrode structure; one end of the initial calibration module is connected to the data selection and current source table module, and the other end is connected to one end of the reconstruction spectrum module, and the other end of the reconstruction spectrum module is connected to the data selection and current source table module.

[0036] Beneficial effects: The gradient bandgap photodiode reconstruction spectrometer of this embodiment has a gradient bandgap photodiode detector with a photodiode array with different bandgaps. On the one hand, such a gradient bandgap photodiode array can respond to light under different bias voltages and can directly convert optical signals into different electrical signals without the need for additional prisms, filters, CMOS image sensors, driving voltages and other structures; on the other hand, the gradient bandgap photodiode detector integrates photodiode arrays with different bandgaps together, which is smaller than conventional spectrometers. Ultimately, while achieving miniaturization, integration and low cost of the reconstruction spectrometer, it can obtain linear changes and a larger dynamic range, which helps to improve the accuracy of spectral reconstruction and the resolution of the spectrometer. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0038] Figure 1 is a flowchart of a method for preparing a gradient bandgap photodiode detector according to an embodiment of the present invention;

[0039] Figure 2 is a schematic structural diagram of an embodiment of the present invention after a conductive layer is formed on a substrate;

[0040] Figure 3 is a schematic structural diagram of forming a first carrier transport layer on a substrate according to an embodiment of the present invention;

[0041] Figure 4 is a schematic structural diagram of forming an initial semiconductor photosensitive layer on a first carrier transport layer according to an embodiment of the present invention;

[0042] Figure 5 is a schematic diagram of immersing an initial semiconductor photosensitive layer into a reaction solution according to an embodiment of the present invention;

[0043] Figure 6 is a schematic diagram of the structure after forming a gradient bandgap semiconductor photosensitive layer according to an embodiment of the present invention;

[0044] Figure 7 It is a schematic structural diagram of forming a second carrier transport layer on a gradient bandgap semiconductor photosensitive layer according to an embodiment of the present invention;

[0045] Figure 8 is a schematic structural diagram of a gradient bandgap photodiode detector after forming a first electrode structure and a second electrode structure according to an embodiment of the present invention;

[0046] Fig. 9 It is a schematic structural diagram of a gradient bandgap photodiode reconstruction spectrometer according to an embodiment of the present invention.

[0047] Description of reference numerals:

[0048] 1. substrate; 2. conductive layer; 3. first carrier transport layer; 4. initial semiconductor photosensitive layer; 5. gradient bandgap semiconductor photosensitive layer; 6. second carrier transport layer; 7. first electrode structure; 8. second electrode structure;

[0049] 10. Clamping assembly; 20. Reaction container;

[0050] 100, gradient bandgap photodiode detector; 200, data selection and current source meter module; 300, initial calibration module; 400, spectrum reconstruction module; DETAILED DESCRIPTION

[0051] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It is understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only some structures related to the present invention are shown in the accompanying drawings, rather than all structures. In the following description, the description of known structures and technologies is omitted to avoid unnecessary confusion of the concept of the present invention. Various structural schematic diagrams according to embodiments of the present invention are shown in the accompanying drawings. These figures are not drawn to scale, and some details are magnified for the purpose of clear expression, and some details may be omitted. The shapes of various regions and layers shown in the figures and the relative sizes and positional relationships between them are only exemplary, and may be deviated due to manufacturing tolerances or technical limitations in practice, and those skilled in the art may additionally design regions / layers with different shapes, sizes, and relative positions according to actual needs. In the context of the present invention, when a layer / element is referred to as being "on" another layer / element, the layer / element may be directly on the other layer / element, or there may be an intermediate layer / element between them. In addition, if one layer / element is "on" another layer / element in one orientation, then when the orientation is reversed, the layer / element may be "below" the other layer / element.

[0052] refer to Figures 1 to 8 This embodiment provides a method for preparing a gradient bandgap photodiode detector. Figure 1 The flowchart of the preparation method of the gradient bandgap photodiode detector is shown in FIG. 1 , and the preparation method comprises the following steps:

[0053] Step S101, providing a substrate 1.

[0054] For example, in this embodiment, a rectangular glass with a width of 15 mm is selected as the substrate 1, or a square glass with a side length of 15 mm is selected as the substrate 1, and no specific requirement is made on the thickness of the substrate 1.

[0055] Step S102 , forming a conductive layer 2 on one side surface of the substrate 1 .

[0056] refer to Figure 2 In this embodiment, a very thin layer of indium tin oxide (ITO for short) material is deposited on the upper surface of the substrate 1 as the conductive layer 2. The length of the conductive layer 2 is equal to the length of the substrate 1, and the width can be equal to or less than the width of the substrate 1.

[0057] Furthermore, the conductive layer 2 may also be fluorine-doped tin oxide (FTO for short).

[0058] Step S103 , forming a first carrier transport layer 3 on a surface of the substrate 1 having the conductive layer 2 .

[0059] For example, the first carrier transport layer 3 may be an electron transport layer or a hole transport layer. In this embodiment, the first carrier transport layer 3 is configured as an electron transport layer, and the first carrier transport layer 3 is obtained by spin coating a tin dioxide colloidal solution on one side of the upper surface of the substrate 1 and then annealing the solution. Figure 3 As shown, the first carrier transport layer 3 covers at least part of the conductive layer 2 and part of the substrate 1. The concentration of the tin dioxide colloidal solution is in the range of 6% to 12%, the annealing temperature is in the range of 150° C. to 160° C., and the annealing time is in the range of 15 min to 25 min.

[0060] Furthermore, the material of the first carrier transport layer 3 serving as the electron transport layer includes titanium dioxide, zinc oxide or tin dioxide; tin dioxide is preferred in this embodiment.

[0061] Step S104 , forming an initial semiconductor photosensitive layer 4 on a surface of the first carrier transport layer 3 facing away from the substrate 1 .

[0062] like Figure 4 As shown, an initial semiconductor photosensitive material is spin-coated on the first carrier transport layer 3 to form an initial semiconductor photosensitive layer 4 having the same size as the first carrier transport layer 3 .

[0063] In step S105 , the substrate 1 having the conductive layer 2 , the first carrier transport layer 3 and the initial semiconductor photosensitive layer 4 is gradually immersed in the reaction solution from the first end of the substrate 1 along a first preset direction.

[0064] In this embodiment, the length direction of the substrate 1 deposited with the conductive layer 2, the first carrier transport layer 3 and the initial semiconductor photosensitive layer 4 is used as the first preset direction, the left end of the substrate 1 is used as the first end, and the right end is used as the second end. That is, the substrate 1 with the conductive layer 2, the first carrier transport layer 3 and the initial semiconductor photosensitive layer 4 is rotated 90°, and the first end is used as the bottom end to be immersed in the reaction solution from top to bottom to perform ion exchange reaction, and the initial immersion time is 0 to 20 minutes.

[0065] Step S106, pulling the substrate 1 out of the reaction solution along the first preset direction from the first end of the substrate 1 toward the second end opposite to the first end, so as to form a gradient bandgap semiconductor photosensitive layer 5 with a bandgap gradually changing along the first preset direction.

[0066] refer to Figure 5 After at least part of the substrate 1 having the conductive layer 2, the first carrier transport layer 3 and the initial semiconductor photosensitive layer 4 is immersed in the reaction solution, it is slowly pulled out from bottom to top, so that the immersion time of different regions of the initial semiconductor photosensitive layer 4 from bottom to top in the reaction solution is gradually shortened, until the substrate 1 having the conductive layer 2, the first carrier transport layer 3 and the initial semiconductor photosensitive layer 4 completely leaves the reaction solution, and is turned back to the initial horizontal placement state, and the initial semiconductor photosensitive layer 4 becomes a gradient bandgap semiconductor photosensitive layer 5 with different components in different regions in the horizontal direction, such as Figure 6 shown.

[0067] Step S107 , forming a second carrier transport layer 6 on the surface of the gradient bandgap semiconductor photosensitive layer 5 facing away from the substrate 1 .

[0068] refer to Figure 7 In this embodiment, on the upper surface of the gradient bandgap semiconductor photosensitive layer 5, a second carrier transport layer 6 of the same size as the gradient bandgap semiconductor photosensitive layer 5 is formed by spin coating a 2,2',7,7'-tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9'-spirobifluorene (Sprio-OMeTAD for short) solution. One of the first carrier transport layer 3 and the second carrier transport layer 6 is an electron transport layer, and the other is a hole transport layer. In this embodiment, the first carrier transport layer 3 is an electron transport layer, and the second carrier transport layer 6 is a hole transport layer. The concentration of the 2,2',7,7'-tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9'-spirobifluorene solution for preparing the hole transport layer is 72.3 mg / mL.

[0069] Furthermore, the material of the second carrier transport layer serving as the hole transport layer may be selected from one or more of P3HT, Spiro-OMeTAD, and PTAA.

[0070] Step S108 , forming a plurality of first electrode structures 7 on the surface of the second carrier transport layer 6 facing away from the substrate 1 , and forming a second electrode structure 8 on the substrate 1 ; the plurality of first electrode structures 7 are arranged in an array, and the second electrode structure 8 is connected to the conductive layer 2 .

[0071] refer to Figure 8 A plurality of first electrode structures 7 are arranged in an array on the upper surface of the second carrier transport layer 6, and a second electrode structure 8 is arranged on the exposed portion of the substrate 1, and the second electrode structure 8 is connected to the conductive layer 2. In this embodiment, the thickness of the first electrode structure 7 and the second electrode structure 8 is 60 nm, and they are made of metal material gold, which has excellent conductive properties.

[0072] Furthermore, the first electrode structure 7 can be a silver electrode, a gold electrode or a copper electrode; in this embodiment, it is preferably a gold electrode. Similarly, the second electrode structure 8 can be a silver electrode, a gold electrode or a copper electrode; in this embodiment, it is preferably a gold electrode.

[0073] The preparation method of the gradient bandgap photodiode detector of the present embodiment forms a gradient bandgap semiconductor photosensitive layer 5 by exchanging halogen ions in a solution, and forms a first carrier transport layer 3 and a second carrier transport layer 6, i.e., an electron transport layer and a hole transport layer, on the upper and lower sides of the gradient bandgap semiconductor photosensitive layer 5 by a method such as spin coating, thereby forming a pin-type or nip-type photodiode structure, and then a plurality of first electrode structures 7 arranged in an array are provided, and finally a photodiode-type photodetector with a gradient bandgap is formed, which converts a light signal incident from the direction of the substrate 1 into an electrical signal, and improves the extraction of photogenerated carriers on the basis of ensuring that the gradient bandgap semiconductor photosensitive layer 5 has different spectral responses, so that the photodetector has a wide dynamic response range and a fast response speed. The gradient bandgap semiconductor photosensitive layer 5 and the array-arranged first electrode structure 7 constitute a photodiode array photodetector array, which contributes to the accuracy of the linear solution of the spectral reconstruction algorithm, and has the characteristics of high spectral resolution, simple process and easy integration.

[0074] In one embodiment, the material of the substrate includes any one or more of glass, quartz, sapphire, polyethylene naphthalate, polyimide, polyvinylidene fluoride, polyetherimide, and polyethylene terephthalate plastics. The selection of different substrate materials helps to improve the applicability of the gradient bandgap photodiode detector.

[0075] like Figure 2 and Figure 3 As shown, the conductive layer 2 of this embodiment is located on a partial surface of one side of the substrate 1; the first carrier transport layer 3 covers a portion of the substrate 1 to expose a portion of the substrate 1 and a portion of the conductive layer 2, and the second electrode structure 8 is arranged on the exposed substrate 1 to be connected to the conductive layer 2.

[0076] Specifically, in this embodiment, the length of the conductive layer 2 is set to 15 mm, and the width is set to 8 mm, that is, the conductive layer 2 is set in the middle position of the upper surface of the substrate 1, and the upper surface of the substrate 1 has a portion exposed in the width direction; along the first preset direction, that is, the length direction of the substrate 1, the length of the first carrier transport layer 3 is less than the length of the substrate 1, that is, the left end of the first carrier transport layer 3 is aligned with the left end of the substrate 1, and the front end and the rear end can also be aligned accordingly, and the right end portion of the substrate 1 is exposed, that is, part of the substrate 1 and the conductive layer 2 on the right side are exposed, and the second electrode structure 8 is arranged on the exposed substrate 1 and is connected to the conductive layer 2.

[0077] In a vertically stacked device, the current density is calculated by dividing the measured current value by the effective area of ​​the device, that is, the coupling area between the first electrode structure 7 and the second electrode structure 8 and the conductive layer 2. Compared with depositing the conductive layer 2 on the entire surface, using a partially deposited conductive layer 2 can more accurately control the size of the effective area of ​​the device and improve the accuracy of the reconstructed spectrum. In this embodiment, the width of the first electrode structure 7 and the second electrode structure 8 is set to 0.5 mm, and the width of the conductive layer 2 is set to 8 mm, which helps to form the coupling area between the conductive layer 2 and the electrode structure, that is, the effective area of ​​the device is 1 mm 2 .

[0078] It is understandable that the exposed portion may also be on the left side, as long as a space for arranging the second electrode structure 8 is provided, and when immersed in the reaction solution, the end relatively far from the second electrode structure 8 starts to contact the reaction solution.

[0079] Of course, the first carrier transport layer 3 may be arranged to be not aligned with the left end of the substrate 1, but to have a certain offset; in this embodiment, the first carrier transport layer 3 and other structures are arranged to be aligned with the left end of the substrate 1 in order to facilitate the consistency and controllability of each layer structure for stacking and immersion in the reaction solution.

[0080] In one embodiment, the above step S104, forming an initial semiconductor photosensitive layer 4 on a surface of the first carrier transport layer 3 facing away from the substrate 1, comprises:

[0081] Step S1041 , coating iodine lead methylamine on the surface of the first carrier transport layer 3 facing away from the substrate 1 .

[0082] Specifically, the iodine-lead-methylamine solution is coated on the upper surface of the first carrier transport layer 3 by spin coating. In this embodiment, the concentration of the iodine-lead-methylamine solution is 0.5M to 1.5M, which helps to form a complete and effective semiconductor photosensitive layer.

[0083] Step S1042, annealing the iodine lead methylamine to form an initial semiconductor photosensitive layer 4.

[0084] Specifically, the iodine lead methylamine solution is annealed at a temperature range of 100° C. to 110° C. for 10 min to 60 min to form a stable and reliable iodine lead methylamine initial semiconductor photosensitive layer 4 .

[0085] An initial semiconductor photosensitive layer 4 of iodine lead methylamine is formed by spin coating and annealing, which provides a basis for the subsequent formation of a gradient band gap semiconductor photosensitive layer 5 by halogen ion exchange.

[0086] In one embodiment, the material of the initial semiconductor photosensitive layer 4 includes any one of iodine lead methylamine, other metal halide perovskites, cadmium selenide sulfide, indium gallium nitride, silicon germanium alloy, and organic semiconductors; the method for forming the initial semiconductor photosensitive layer 4 includes any one or more of spin coating, spray coating, slit coating, inkjet printing, thermal evaporation, and metal organic chemical vapor deposition. The initial semiconductor photosensitive layer 4 includes a variety of materials, and there are also a variety of ways to form it, providing a variety of possible applications of the initial semiconductor photosensitive layer 4.

[0087] The above step S105, wherein the substrate 1 having the conductive layer 2, the first carrier transport layer 3 and the initial semiconductor photosensitive layer 4 is gradually immersed in the reaction solution from the first end of the substrate 1 along the first preset direction, comprises:

[0088] Step S1051 , fixing the side of the second end of the substrate 1 where the initial semiconductor photosensitive layer 4 is not provided on the clamping assembly 10 .

[0089] like Figure 5 As shown, the substrate 1 having a conductive layer 2, a first carrier transport layer 3 and an initial semiconductor photosensitive layer 4 is rotated 90° so that the left end of the substrate 1 faces downward and the right end is fixed on the clamping assembly 10 as the upper end, and the clamping assembly 10 contacts the back side of the substrate 1 where structures such as the conductive layer 2 are not provided, so as to avoid damage to the various structural layers on the substrate 1.

[0090] Step S1052 , immersing the substrate 1 gradually into the reaction solution from the first end opposite to the second end along a first preset direction until a section of the initial semiconductor photosensitive layer 4 close to the second end is at a preset distance from the surface of the reaction solution.

[0091] The rotated substrate 1 having the conductive layer 2, the first carrier transport layer 3 and the initial semiconductor photosensitive layer 4 is immersed from top to bottom into the reaction solution in the reaction container 20. In this embodiment, the initial semiconductor photosensitive layer 4 is not completely immersed in the reaction solution to provide a larger band gap gradient range.

[0092] By rotating the substrate 1 having a conductive layer 2, a first carrier transport layer 3 and an initial semiconductor photosensitive layer 4, the initial semiconductor photosensitive layer 4 forms band gap regions with different component ranges on the plane, and using a clamping assembly 10 with scale markings to perform position changes in the height range helps to achieve precise gradient range control, thereby ensuring the accuracy of the linear solution of the spectral reconstruction algorithm.

[0093] In one embodiment, the reaction solution comprises an isopropanol solution containing methylammonium bromide, wherein the concentration of methylammonium bromide is 10 mg / mL.

[0094] The initial semiconductor photosensitive layer 4 of iodine lead methylamine is exchanged with methyl ammonium bromide for halogen ions in an isopropanol solution to form a gradient bandgap semiconductor photosensitive layer 5 which gradually transitions from iodine lead methylamine to bromide lead methylamine, thereby enabling the photodiode-type photodetector to have different light response ranges and form a linearly varying dynamic range, providing conditions for obtaining different responsiveness in the spectrometer, thereby improving the accuracy of the linear solution of the spectral reconstruction algorithm.

[0095] In one embodiment, the preset distance in the above step S1052 is set to 0.75 mm. That is, the area of ​​the initial semiconductor photosensitive layer 4 with a length of 0.75 mm is reserved and is not immersed in the isopropanol solution containing methylammonium bromide, and the range of the reserved area is precisely controlled to ensure that the initial semiconductor photosensitive layer 4 has a partial area that is completely iodine lead methylamine.

[0096] In one embodiment, the width of the first electrode structure 7 is 0.5 mm, and the width of the second electrode structure 8 is 0.5 mm; the spacing between adjacent first electrode structures 7 is 0.5 mm, and the number of the first electrode structures 7 is a multiple of 12.

[0097] like Figure 8 As shown, in this embodiment, two groups of first electrode structures 7 are arranged along the width direction of the substrate 1, and each group of first electrode structures 7 includes 12 first electrode structures 7 arranged at intervals along the length direction. The width of the first electrode structure 7 and the second electrode structure 8 is reasonably set to 0.5 mm, and the spacing between adjacent first electrode structures 7 is also set to 0.5 mm, which helps to control the size of the coupling area between the first electrode structure 7 and the second electrode structure 8 and the conductive layer 2. In this embodiment, the bottom conductive layer 2 and the first electrode structure 7 and the second electrode structure 8 are separated, the process is simple, and the number of electrode structures is reduced while ensuring that the gradient bandgap photodiode works independently, which is convenient for measurement. The rational design of the area and spacing of the first electrode structure 7 and the second electrode structure 8 helps to reduce the size of the photodetector and the spectrometer.

[0098] In one embodiment, in step S102, after forming a conductive layer 2 on one side surface of the substrate 1, and before forming a first carrier transport layer 3 on one side surface of the substrate 1 having the conductive layer 2, in step S103, it also includes: performing a first cleaning treatment on the substrate 1 having the conductive layer 2; and blowing drying the substrate 1 after the first cleaning treatment.

[0099] Specifically, the first cleaning treatment includes placing the substrate 1 into containers filled with deionized water, anhydrous ethanol, anhydrous acetone and anhydrous ethanol in turn, so that the substrate 1 is completely immersed in the solution, and placing it in an ultrasonic cleaning machine for cleaning, and the ultrasonic cleaning time is set to 15 minutes; after the first cleaning treatment, the liquid on the surface is blown dry with nitrogen, and specifically a nitrogen gun can be used for uniform and efficient drying treatment to ensure the subsequent setting of the first carrier transport layer 3.

[0100] In addition, after forming the gradient bandgap semiconductor photosensitive layer 5 in step S106 and before forming the second carrier transport layer 6 on the surface of the gradient bandgap semiconductor photosensitive layer 5 facing away from the substrate 1 in step S107, it also includes: performing a second cleaning treatment on the substrate 1 having the gradient bandgap semiconductor photosensitive layer 5; and drying the substrate 1 after the second cleaning treatment.

[0101] Specifically, the second cleaning treatment includes rinsing with anhydrous ethanol to remove the reaction solution remaining on the surface of the sample in step S106; then, the sample after the second cleaning treatment is placed on a hot table for drying, the drying temperature is set to 100°C, and the drying time is 10min to 30min to obtain a dry and stable gradient bandgap semiconductor photosensitive layer 5 that gradually transitions from iodine lead methylamine to bromide lead methylamine.

[0102] like Figure 8 As shown, the present embodiment also provides a gradient bandgap photodiode detector 100, which is manufactured by the above-mentioned preparation method of the gradient bandgap photodiode detector, including: a substrate 1, a conductive layer 2, a first carrier transport layer 3, a gradient bandgap semiconductor photosensitive layer 5, a second carrier transport layer 6, a plurality of first electrode structures 7 and a second electrode structure 8, wherein the conductive layer 2 is arranged on one side surface of the substrate 1; the first carrier transport layer 3 is arranged on one side surface of the substrate 1 having the conductive layer 2; the gradient bandgap semiconductor photosensitive layer 5 is arranged on the side surface of the first carrier transport layer 3 away from the substrate 1, and the bandgap of the gradient bandgap semiconductor photosensitive layer 5 gradually changes along a first preset direction; the second carrier transport layer 6 is arranged on the side surface of the gradient bandgap semiconductor photosensitive layer 5 away from the substrate 1; a plurality of first electrode structures 7 are arranged on the side surface of the second carrier transport layer 6 away from the substrate 1, and the plurality of first electrode structures 7 are arranged in an array; the second electrode structure 8 is arranged on the substrate 1 and connected to the conductive layer 2.

[0103] The gradient bandgap photodiode detector 100 of the present embodiment has a first carrier transport layer 3 and a second carrier transport layer 6, i.e., an electron transport layer and a hole transport layer, arranged on the upper and lower sides of the gradient bandgap semiconductor photosensitive layer 5, thereby forming a pin-type or nip-type photodiode structure. Then, the pin-type or nip-type photodiode structure and a plurality of first electrode structures 7 arranged in an array constitute a photodiode array photodetector with a gradient bandgap, which converts light signals incident from the direction of the substrate 1 into electrical signals. While ensuring that the gradient bandgap semiconductor photosensitive layer 5 has different spectral responses, the extraction of photogenerated carriers is improved, so that the photodetector has a wide and linearly changing dynamic response range and a fast response speed, which is conducive to the accuracy of the linear solution of the spectral reconstruction algorithm, and has the characteristics of high spectral resolution, simple process and easy integration.

[0104] like Fig. 9 As shown, the present embodiment further provides a gradient bandgap photodiode reconstruction spectrometer, comprising: the above-mentioned gradient bandgap photodiode detector 100, a data selection and current source table module 200, an initial calibration module 300 and a reconstruction spectrum module 400, wherein one end of the data selection and current source table module 200 is respectively connected to a plurality of first electrode structures 7, and the other end is connected to the second electrode structure 8; one end of the initial calibration module 300 is connected to the data selection and current source table module 200, and the other end is connected to one end of the reconstruction spectrum module 400, and the other end of the reconstruction spectrum module 400 is connected to the data selection and current source table module 200.

[0105] Specifically, the gradient bandgap photodiode detector 100 converts the optical signal of the incident light to be measured into different electrical signals I i (i=1,2,…,12), the data selection and current source meter module 200 reads different electrical signal values, and the gradient bandgap photodiode detector 100 also inputs electrical signals to the initial calibration module 300 during calibration, so that the initial calibration module 300 outputs the response R when different wavelengths of light are incident. i (λ)(i=1,2,…,12), the spectrum reconstruction module 400 is used to solve the equation system λ1 and λ2 are the start and end wavelengths measured by the spectrometer. Then, F(λ) is obtained through Tikhonov regularization, which is the result measured by the spectrometer.

[0106] The gradient bandgap photodiode reconstruction spectrometer of the present embodiment has a gradient bandgap photodiode detector 100 with a photodiode array with different bandgaps. On the one hand, such a gradient bandgap photodiode array can respond to light under different bias voltages and can directly convert optical signals into different electrical signals without the need for additional prisms, filters, CMOS image sensors, driving voltages and other structures. On the other hand, the gradient bandgap photodiode detector 100 integrates photodiode arrays with different bandgaps together, which is smaller than conventional spectrometers. Ultimately, while achieving miniaturization, integration and low cost of the reconstruction spectrometer, it can obtain linear changes and a larger dynamic range, which helps to improve the accuracy of spectral reconstruction and the resolution of the spectrometer.

[0107] The further functional description of each of the above modules and units is the same as that of the above corresponding embodiments and will not be repeated here.

[0108] In the above description, the technical details of the patterning and etching of each layer are not described in detail. However, those skilled in the art should understand that various technical means can be used to form layers, regions, etc. of desired shapes. In addition, in order to form the same structure, those skilled in the art can also design methods that are not completely the same as the methods described above. In addition, although the various embodiments are described above separately, this does not mean that the measures in the various embodiments cannot be used in combination to advantage.

[0109] Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations are all within the scope defined by the appended claims.

Claims

1. A method for preparing a gradient bandgap photodiode detector, characterized in that: include: providing a substrate; forming a conductive layer on a surface of one side of the substrate; Forming a first carrier transport layer on a surface of the substrate having the conductive layer; forming an initial semiconductor photosensitive layer on a surface of the first carrier transport layer facing away from the substrate; The substrate having the conductive layer, the first carrier transport layer and the initial semiconductor photosensitive layer is gradually immersed in a reaction solution from a first end of the substrate along a first preset direction; Pulling the substrate out of the reaction solution along the first preset direction from a first end of the substrate toward a second end opposite to the first end, so as to form a gradient bandgap semiconductor photosensitive layer with a bandgap gradually changing along the first preset direction; Forming a second carrier transport layer on a surface of the gradient bandgap semiconductor photosensitive layer that is away from the substrate; A plurality of first electrode structures are formed on a surface of the second carrier transport layer facing away from the substrate, and a second electrode structure is formed on the substrate; the plurality of first electrode structures are arranged in an array, and the second electrode structure is connected to the conductive layer.

2. The method for preparing a gradient bandgap photodiode detector according to claim 1, characterized in that: The material of the substrate includes any one or more of glass, quartz, sapphire, polyethylene naphthalate, polyimide, polyvinylidene fluoride, polyetherimide, and polyethylene terephthalate plastics.

3. The method for preparing a gradient bandgap photodiode detector according to claim 1, characterized in that: The conductive layer is located on a partial surface of one side of the substrate; the first carrier transport layer covers a portion of the substrate to expose a portion of the substrate and a portion of the conductive layer, and the second electrode structure is arranged on the exposed substrate to be connected to the conductive layer.

4. The method for preparing a gradient bandgap photodiode detector according to claim 1, characterized in that: In the initial semiconductor photosensitive layer formed on the surface of the first carrier transport layer facing away from the substrate, the material of the initial semiconductor photosensitive layer includes any one of iodine lead methylamine, other metal halide perovskites, cadmium selenide sulfide, indium gallium nitride, silicon germanium alloy, and organic semiconductors; the method for forming the initial semiconductor photosensitive layer includes any one or more of spin coating, spraying, slit coating, inkjet printing, thermal evaporation, and metal organic chemical vapor deposition.

5. The method for preparing a gradient bandgap photodiode detector according to claim 1, characterized in that: The step of gradually immersing the substrate having the conductive layer, the first carrier transport layer, and the initial semiconductor photosensitive layer into a reaction solution from a first end of the substrate along a first preset direction comprises: Fixing the side of the second end of the substrate where the initial semiconductor photosensitive layer is not provided to a clamping assembly; Along the first preset direction, the substrate is gradually immersed into the reaction solution from a first end opposite to the second end until a section of the initial semiconductor photosensitive layer close to the second end is at a preset distance from the surface of the reaction solution.

6. The method for preparing a gradient bandgap photodiode detector according to claim 4, characterized in that: The reaction solution includes an isopropanol solution with methylammonium bromide.

7. The method for preparing a gradient bandgap photodiode detector according to claim 5, characterized in that: The preset distance is 0.75 mm.

8. The method for preparing a gradient bandgap photodiode detector according to claim 1, characterized in that: The width of the first electrode structure is 0.5 mm, and the width of the second electrode structure is 0.5 mm; the spacing between adjacent first electrode structures is 0.5 mm, and the number of the first electrode structures is a multiple of 12.

9. The method for preparing a gradient bandgap photodiode detector according to any one of claims 1 to 8, characterized in that: After forming a conductive layer on one side surface of the substrate and before forming a first carrier transport layer on one side surface of the substrate having the conductive layer, the method further includes: performing a first cleaning treatment on the substrate having the conductive layer; Drying the substrate after the first cleaning process; After forming the gradient bandgap semiconductor photosensitive layer and before forming a second carrier transport layer on a surface of the gradient bandgap semiconductor photosensitive layer facing away from the substrate, the method further includes: performing a second cleaning process on the substrate having the gradient bandgap semiconductor photosensitive layer; The substrate after the second cleaning process is dried.

10. A gradient bandgap photodiode detector, prepared by the method for preparing a gradient bandgap photodiode detector according to any one of claims 1 to 9, characterized in that: include: substrate; A conductive layer is disposed on a surface of one side of the substrate; A first carrier transport layer is disposed on a surface of the substrate having the conductive layer; A gradient bandgap semiconductor photosensitive layer is arranged on a surface of the first carrier transport layer facing away from the substrate, and the bandgap of the gradient bandgap semiconductor photosensitive layer gradually changes along the first preset direction; A second carrier transport layer is arranged on a surface of the gradient bandgap semiconductor photosensitive layer facing away from the substrate; A plurality of first electrode structures are disposed on a surface of the second carrier transport layer facing away from the substrate, and the plurality of first electrode structures are arranged in an array; The second electrode structure is disposed on the substrate and connected to the conductive layer.

11. A gradient bandgap photodiode reconstruction spectrometer, characterized in that: include: The gradient bandgap photodiode detector as claimed in claim 10; as well as, A data selection and current source meter module, one end of which is respectively connected to the first electrode structures, and the other end of which is connected to the second electrode structure; An initial calibration module and a spectrum reconstruction module, one end of the initial calibration module is connected to the data selection and current source table module, and the other end is connected to one end of the spectrum reconstruction module, and the other end of the spectrum reconstruction module is connected to the data selection and current source table module.

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