Selenium-doped mercury telluride quantum dot short-wave infrared detector and preparation method thereof
By introducing a hole transport layer on a selenium-doped mercury telluride quantum dot layer and forming an HgTe thin film using cation exchange, the fabrication problem of existing mercury telluride quantum dot infrared detectors has been solved, realizing a photovoltaic infrared detector with low dark current and high light response, suitable for the short-wave infrared band.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- HANGZHOU HIKVISION DIGITAL TECHNOLOGY CO LTD
- Filing Date
- 2025-01-10
- Publication Date
- 2026-05-19
AI Technical Summary
Existing photovoltaic mercury telluride quantum dot infrared detectors suffer from problems such as unfriendly hole transport layer preparation, uncontrollable Ag+ diffusion affecting PN junction stability, low electron reverse transport probability, and difficulty in synthesizing HgTe quantum dots.
A p-on-n junction structure was adopted, and a hole transport layer was prepared on a selenium-doped mercury telluride quantum dot layer. HgTe quantum dot thin films were formed by cation exchange between CdTe quantum dot solution and HgCl2 solution, which simplified the preparation process and improved the electron affinity potential.
A high-performance photovoltaic infrared detector with low dark current, high light response and wide spectral range has been achieved, which is suitable for short-wave infrared detection and breaks through the size bottleneck of HgTe quantum dot synthesis.
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Figure CN122069797A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of photoelectric detection technology, and specifically relates to a selenium-doped mercury telluride quantum dot short-wave infrared detector and its preparation method. Background Technology
[0002] With the transformation and upgrading of the national industrial structure, artificial intelligence has risen to a major national development strategy, and the development of artificial intelligence is inseparable from sensor technology. Infrared detection, as an important branch of sensor technology, has the characteristics of long detection distance, strong penetration capability, and rich detection information, and can be used in many fields such as autonomous driving, temperature measurement, and component analysis, possessing extremely important application value. Infrared sensor technology is a technical science that studies the generation, propagation, conversion, measurement, and application of infrared radiation from targets and the environment, presented in image form. According to Planck's law and the Stefan-Boltzmann law, the total radiation of an object is proportional to the fourth power of its temperature (E = σT). 4 Infrared radiation energy increases with temperature. Based on this, infrared detectors can detect information about objects, such as temperature, by measuring their radiation levels. Therefore, infrared sensors, such as infrared photodetectors, are widely used in various military and civilian fields. Currently, commonly used infrared photodetectors are quantum dot infrared detectors. Although their performance cannot be compared to traditional infrared detectors such as indium gallium arsenide detectors, they have secured a place in the field of novel infrared detectors due to their easier size adjustment, wide tunable infrared spectral range, ease of fabrication, low cost, and ease of integration with silicon-based readout circuits. Mercury telluride quantum dot materials, in particular, have attracted considerable attention due to their wide infrared spectrum, which can even extend into the long-wave infrared.
[0003] Quantum dot infrared detectors are mainly divided into two categories: photoconductive and photovoltaic. Compared to photoconductive devices, photovoltaic detectors offer superior performance. Existing photovoltaic detectors, such as mercury telluride colloidal quantum dot detectors, mostly employ a bottom-incident p-on-n structure, where the electron transport layer is located below the mercury telluride colloidal quantum dot, while the hole transport layer is located above it. This structure has the following problems:
[0004] (1) The hole transport layer in most device structures is anchored by using mercuric chloride to treat Ag2Te quantum dots to form Ag:HgTe. + To form stable p-type doping, but Ag + The uncontrollable diffusion can affect the formation of a stable and good PN junction;
[0005] (2) The hole transport layer is too complicated to prepare and is not user-friendly to manufacture;
[0006] (3) Photovoltaic devices require a large open-circuit voltage V ocA large electron affinity difference is required between the hole transport layer and the intrinsic layer (i.e., the selenium-doped mercury telluride quantum dot layer) to reduce the probability of electrons back-transporting from the intrinsic layer to the hole transport layer, thereby reducing the device's dark current. However, the synthesis of small-sized HgTe quantum dots in non-aqueous phases is very difficult, with a very large bottleneck in synthesis size. Summary of the Invention
[0007] To address the aforementioned technical problems, this invention provides a selenium-doped mercury telluride quantum dot short-wave infrared detector and its fabrication method.
[0008] In a first aspect, this application provides a method for fabricating a selenium-doped mercury telluride quantum dot short-wave infrared detector, wherein the infrared detector comprises an electron transport layer, a selenium-doped mercury telluride quantum dot layer and a hole transport layer, and the electron transport layer, the selenium-doped mercury telluride quantum dot layer and the hole transport layer form a p-on-n type junction.
[0009] The method includes:
[0010] A selenium-doped mercury telluride quantum dot layer is prepared on one side of the electron transport layer;
[0011] Preparation of CdTe quantum dot solution;
[0012] A CdTe quantum dot solution was spin-coated onto a selenium-doped mercury telluride quantum dot layer and then immersed in a HgCl2 solution to allow cation exchange between the CdTe quantum dot solution and the HgCl2 solution, thereby obtaining an HgTe quantum dot film and thus preparing a hole transport layer.
[0013] The method further includes:
[0014] Provide a base;
[0015] A bottom electrode is fabricated on the substrate;
[0016] The electron transport layer is fabricated on the side of the bottom electrode away from the substrate; wherein the selenium-doped mercury telluride quantum dot layer is disposed on the side of the electron transport layer away from the bottom electrode;
[0017] A top electrode is fabricated on the side of the hole transport layer away from the bottom electrode.
[0018] The preparation of CdTe quantum dot solution includes:
[0019] Cadmium chloride powder is dissolved in oleylamine solution to form a cadmium precursor solution;
[0020] Tellurium oxide and dodecyl mercaptan (DDT) are heated and stirred at a preset temperature to form a tellurium precursor solution;
[0021] The cadmium precursor solution and the tellurium precursor solution were mixed to synthesize a CdTe quantum dot solution.
[0022] The process involves spin-coating a CdTe quantum dot solution onto a selenium-doped mercury telluride quantum dot layer and then immersing it in a HgCl2 solution to allow cation exchange between the CdTe quantum dot solution and the HgCl2 solution, thereby obtaining an HgTe quantum dot film and preparing a hole transport layer. This includes:
[0023] A CdTe quantum dot solution was spin-coated onto a selenium-doped mercury telluride quantum dot layer;
[0024] The solution is soaked in a methanol solution of HgCl2, which allows the cations Cd in the CdTe quantum dot solution to exchange with the cations Hg in the methanol solution of HgCl2.
[0025] Solid-phase ligand exchange was performed using an ethanol solution of 1,2-ethylenedithiol, followed by solvent washing to remove residual ligands, resulting in an HgTe quantum dot film, thereby preparing the hole transport layer.
[0026] The process of fabricating a selenium-doped mercury telluride quantum dot layer on one side of the electron transport layer includes:
[0027] Selenurea powder was dissolved in oleylamine solution and heated under nitrogen to obtain oleylamine-selenourea solution;
[0028] The oleylamine selenide solution was mixed with the tri-n-octylphosphine telluride solution to obtain the selenium-doped mercury telluride precursor solution.
[0029] A selenium-doped mercury telluride precursor solution was added to an oleylamine solution in which HgCl2 was dissolved to synthesize a selenium-doped mercury telluride quantum dot solution.
[0030] A selenium-doped mercury telluride quantum dot solution was spin-coated onto one side of the electron transport layer to prepare a selenium-doped mercury telluride quantum dot layer.
[0031] The thickness of the electron transport layer is 50–100 nm.
[0032] The selenium-doped mercury telluride quantum dot solution is concentrated during spin coating, and the concentration is 1 to 1.5 times that of the selenium-doped mercury telluride quantum dot solution.
[0033] The CdTe quantum dot solution is diluted during spin coating, and the dilution is 2 to 6 times that of the CdTe quantum dot solution.
[0034] The thickness of the selenium-doped mercury telluride quantum dot layer is 400–500 nm, and the thickness of the hole transport layer is 10–60 nm.
[0035] Secondly, this application provides a selenium-doped mercury telluride quantum dot short-wave infrared detector, the infrared detector comprising an electron transport layer, a selenium-doped mercury telluride quantum dot layer and a hole transport layer, wherein the selenium-doped mercury telluride quantum dot layer is located between the electron transport layer and the hole transport layer, and the electron transport layer, the selenium-doped mercury telluride quantum dot layer and the hole transport layer form a p-on-n type junction.
[0036] The hole transport layer is an HgTe quantum dot film, which is obtained by cation exchange between a CdTe quantum dot solution and an HgCl2 solution.
[0037] The infrared detector further includes:
[0038] Base;
[0039] A bottom electrode is disposed on the substrate; wherein the electron transport layer is disposed on the side of the bottom electrode away from the substrate;
[0040] The top electrode is disposed on the side of the hole transport layer away from the bottom electrode.
[0041] The method for fabricating a selenium-doped mercury telluride quantum dot short-wave infrared detector provided in this application has the following beneficial effects:
[0042] (1) In this embodiment of the invention, an electron transport layer, a selenium-doped mercury telluride quantum dot layer, and a hole transport layer are used to construct a p-on-n photovoltaic detector. The device has a specific detectivity of 1.6*10 in the short-wave infrared band. 12 Jones, with superior performance, has excellent applications in the 1300–2500 nm shortwave detection range.
[0043] (2) The Se:HgTe quantum dots used in the selenium-doped mercury telluride quantum dot layer in the embodiments of the present invention are simpler to prepare and have more stable chemical properties than HgTe quantum dots.
[0044] (3) In this embodiment of the invention, a hole transport layer is introduced on a selenium-doped mercury telluride quantum dot layer, and CdTe quantum dot film is exchanged into HgTe small-sized quantum dot film by solid-phase cation exchange. This breaks through the size bottleneck of non-aqueous phase synthesis of HgTe quantum dots, so that there is a large electron affinity difference between the hole transport layer and the selenium-doped mercury telluride quantum dot layer, which reduces dark current and improves carrier separation efficiency, so that the photovoltaic device prepared by it has low dark current and high light response. Attached Figure Description
[0045] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0046] Figure 1 This is a schematic flowchart of an embodiment of a method for fabricating a selenium-doped mercury telluride quantum dot short-wave infrared detector disclosed in this application.
[0047] Figure 2 This is a schematic flowchart of another embodiment of the fabrication method of a selenium-doped mercury telluride quantum dot short-wave infrared detector disclosed in this application;
[0048] Figure 3 This is a schematic diagram of the structure of an embodiment of a selenium-doped mercury telluride quantum dot short-wave infrared detector disclosed in this application. Detailed Implementation
[0049] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0050] Please see Figure 1 , Figure 1 This is a schematic flowchart illustrating an embodiment of the fabrication method of a selenium-doped mercury telluride quantum dot short-wave infrared detector disclosed in this application. The selenium-doped mercury telluride quantum dot short-wave infrared detector of this application is a photovoltaic-type short-to-mid-infrared detector. This infrared detector includes an electron transport layer, a selenium-doped mercury telluride quantum dot layer, and a hole transport layer, which form a p-on-n junction; that is, the electron transport layer is located below the mercury telluride colloidal quantum dots, while the hole transport layer is located above the mercury telluride colloidal quantum dots.
[0051] like Figure 1 As shown, the fabrication method of the selenium-doped mercury telluride quantum dot short-wave infrared detector of this application includes:
[0052] Step S11: Prepare a selenium-doped mercury telluride quantum dot layer on one side of the electron transport layer.
[0053] Please combine Figure 2 , Figure 2This is a schematic flowchart of another embodiment of the fabrication method of a selenium-doped mercury telluride quantum dot short-wave infrared detector disclosed in this application, compared to... Figure 1 The embodiment shown, Figure 2 The illustrated embodiment further includes the following steps before step S11:
[0054] Step S21: Provide a substrate.
[0055] The substrate supports the various layers of the infrared detector. The substrate can be any of glass, silicon wafer, quartz wafer, sapphire wafer, or flexible substrate. In one embodiment, the substrate is a quartz wafer with dimensions of length × width × thickness = 25mm × 25mm × 1mm.
[0056] Step S22: Prepare a bottom electrode on the substrate.
[0057] A bottom electrode is deposited on a substrate. The bottom electrode is made of indium tin oxide (ITO) and is a circular electrode with a diameter of 2 mm.
[0058] Specifically, magnetron sputtering is performed on a quartz substrate to sputter an ITO thin film with a thickness of 180 nm as the bottom electrode.
[0059] Step S23: Prepare the electron transport layer on the side of the bottom electrode away from the substrate.
[0060] In one embodiment, the electron transport layer is a Bi₂S₃ thin film with a thickness of 50–100 nm. Specifically, magnetron sputtering is performed on the side of the bottom electrode away from the substrate to sputter a Bi₂S₃ thin film with a thickness of 50–100 nm to obtain the electron transport layer. Preferably, the thickness of the electron transport layer is 80 nm.
[0061] After fabricating the electron transport layer, a selenium-doped mercury telluride quantum dot layer is further fabricated on the side of the electron transport layer away from the substrate. That is, the selenium-doped mercury telluride quantum dot layer is located on the side of the electron transport layer away from the bottom electrode. Please refer to [link to documentation] for details. Figure 1 Step S11.
[0062] Step S11 specifically includes: preparing a selenium-doped mercury telluride precursor solution, and then using the selenium-doped mercury telluride precursor solution to prepare a selenium-doped mercury telluride quantum dot layer.
[0063] Selenurea powder was dissolved in oleylamine solution and heated under nitrogen atmosphere to obtain oleylamine-selenourea solution. Specifically, 126 mg of selenourea powder was dissolved in 1 mL of oleylamine solution, heated to 210 °C under nitrogen atmosphere and maintained for 2 hours until the selenourea powder was completely dissolved, and then cooled to room temperature to obtain 1 mmol / mL oleylamine-selenourea solution.
[0064] A solution of oleylamine selenourea and a solution of tri-n-octylphosphine telluride are mixed to obtain a selenium-doped mercuric telluride precursor solution. For example, a solution of oleylamine selenourea is mixed with a 1 mmol / mL solution of tri-n-octylphosphine telluride to obtain a selenium-doped mercuric telluride precursor solution. In the embodiments of this application, the selenium-doped mercuric telluride precursor solution is a mixed precursor solution of trioctylphosphine telluride (TOPTe) and oleylamine selenourea solution.
[0065] A selenium-doped mercuric telluride precursor solution was added to an oleylamine solution containing long-chain ligands to synthesize a selenium-doped mercuric telluride quantum dot solution (Se:HgTe quantum dot solution) with an absorption cutoff wavelength of 1300 nm to 2500 nm. Specifically, the selenium-doped mercuric telluride precursor solution was added to an oleylamine solution containing dissolved HgCl2 to synthesize the selenium-doped mercuric telluride quantum dot solution. For example, the selenium-doped mercuric telluride precursor solution was added to 15 mL of oleylamine solution containing 276 mg of dissolved HgCl2 using a hot-injection method to synthesize the selenium-doped mercuric telluride quantum dot solution. Specifically, the temperature of the hot-injection method can be controlled to synthesize a quantum dot solution with a predetermined absorption cutoff wavelength. For example, a selenium-doped mercuric telluride quantum dot solution with an absorption cutoff wavelength of approximately 1700 nm was synthesized at 65 °C, washed once with ethanol, and then dispersed in an octane solution for later use.
[0066] A selenium-doped mercury telluride quantum dot layer is prepared by spin-coating a selenium-doped mercury telluride quantum dot solution onto one side of the electron transport layer. Specifically, the selenium-doped mercury telluride quantum dot solution is spin-coated onto one side of the electron transport layer, and then immersed in a methanol solution of HgCl2 to undergo cation exchange (Se in the Se:HgTe quantum dot solution and Hg in the methanol solution of HgCl2 exchange), followed by solid-phase ligand exchange using an ethanol solution of 1,2-ethanedithiol. After both exchanges, the film needs to be washed twice with a solvent to remove residual ligands. This process is repeated 8-10 times to prepare the selenium-doped mercury telluride quantum dot layer. The molar concentration of the methanol solution of HgCl2 is 5 mM to 40 mM (1 mM = 1 mmol / mL), preferably 20 mM, and the volume concentration of the ethanol solution of 1,2-ethanedithiol is 0.05‰ to 1‰, preferably 0.2‰.
[0067] In one embodiment, the selenium-doped mercury telluride quantum dot solution is concentrated during spin-coating to a concentration of 1 to 1.5 times that of the selenium-doped mercury telluride quantum dot solution. For example, the selenium-doped mercury telluride quantum dot solution (Se:HgTe quantum dot solution) is concentrated by 1.125 times and spin-coated onto the electron transport layer. The spin-coating speed is 1000 to 4000 rpm, preferably 2500 rpm, the spin-coating acceleration is 100 to 1000 radians per square second, preferably 500 radians per square second, and the spin-coating time is 5 to 30 seconds per coat, preferably 20 seconds. The thickness of the selenium-doped mercury telluride quantum dot layer is 400 to 500 nm, preferably 450 nm.
[0068] After fabricating the selenium-doped mercury telluride quantum dot layer, a hole transport layer was fabricated on top of the selenium-doped mercury telluride quantum dot layer. See details below. Figure 1 Steps S12 and S13:
[0069] Step S12: Prepare CdTe quantum dot solution.
[0070] Specifically, cadmium chloride powder is dissolved in oleylamine solution to form a cadmium precursor solution. For example, a certain amount of cadmium chloride powder is dissolved in oleylamine at 120°C to form a cadmium precursor solution.
[0071] Tellurium oxide and dodecyl mercaptan (DDT) are heated and stirred at a preset temperature to form a tellurium precursor solution. For example, tellurium oxide (TeO) and DDT are heated and stirred at a preset temperature, such as 180°C, to form a clear orange tellurium precursor solution.
[0072] The cadmium precursor solution and the tellurium precursor solution are mixed to synthesize a CdTe quantum dot solution. It should be noted that the molar ratio of cadmium ions in the cadmium precursor solution to tellurium ions in the tellurium precursor solution is Cd:Te = 1.4:1. The cadmium precursor solution and the tellurium precursor solution are mixed and reacted at a temperature of 160℃~220℃, preferably 200℃, for 3-5 minutes (preferably 3 minutes) to synthesize a CdTe quantum dot solution with an absorption peak position of 440~800nm, preferably 630nm. Then, a quenching solution is added to terminate the reaction and the mixture is washed. The quenching solution is prepared from n-octane and oleic acid, and after washing three times, it is dispersed in n-octane solution at a concentration of 50mg / mL for later use.
[0073] Step S13: Spin-coat a CdTe quantum dot solution onto a selenium-doped mercury telluride quantum dot layer, and then soak it in a HgCl2 solution to allow cation exchange between the CdTe quantum dot solution and the HgCl2 solution, thereby obtaining an HgTe quantum dot film and preparing a hole transport layer.
[0074] Specifically, a CdTe quantum dot solution is spin-coated onto a selenium-doped mercury telluride quantum dot layer. In one embodiment, the CdTe quantum dot solution is diluted during spin-coating to a concentration 2 to 6 times that of the CdTe quantum dot solution. For example, in one embodiment, the CdTe quantum dot solution is diluted 6 times before spin-coating onto the selenium-doped mercury telluride quantum dot layer. The layer is then immersed in a methanol solution of HgCl2 to allow the Cd cations in the CdTe quantum dot solution to exchange with the Hg cations in the methanol solution of HgCl2. Solid-phase ligand exchange is performed using an ethanol solution of 1,2-ethanedithiol, and the film is then washed with a solvent to remove residual ligands, yielding an HgTe quantum dot film, thus preparing the hole transport layer. It should be noted that when performing solid-phase ligand exchange using the ethanol solution of 1,2-ethanedithiol, the film needs to be washed twice with a solvent after each of the two exchanges to remove residual ligands. This process is repeated three times to prepare the hole transport layer. The molar solubility of the HgCl2 methanol solution is 5 mM to 40 mM (1 mM = 1 mmol / mL), preferably 20 mM. The volumetric solubility of the 1,2-ethylenedithiol ethanol solution is 0.05‰ to 1‰, preferably 0.2‰. The spin coating speed is 1000 to 4000 rpm, preferably 1200 rpm; the spin coating acceleration is 100 to 1000 radians per square second, preferably 500 radians per square second; and the coating time is 5 to 30 seconds per coat, preferably 20 seconds per coat.
[0075] In one embodiment, the hole transport layer thickness is 10–60 nm. Preferably, the hole transport layer thickness is 35 nm.
[0076] Please continue reading Figure 2 After the hole transport layer is prepared through the above step S13, the next step S24 is to prepare the top electrode on the side of the hole transport layer away from the bottom electrode.
[0077] In one embodiment, an Au electrode is deposited on the hole transport layer by thermal evaporation deposition to form a top electrode. The thickness of the top electrode is 50–120 nm, with 100 nm being optimal.
[0078] The infrared detector prepared by the method implemented in this application has the following beneficial effects:
[0079] (1) In this embodiment of the invention, an electron transport layer, a selenium-doped mercury telluride quantum dot layer, and a hole transport layer are used to construct a p-on-n photovoltaic detector. The device has a specific detectivity of 1.6*10 in the short-wave infrared band. 12 Jones, with superior performance, has excellent applications in the 1300–2500 nm shortwave detection range.
[0080] (2) The Se:HgTe quantum dots used in the selenium-doped mercury telluride quantum dot layer in the embodiments of the present invention are simpler to prepare and have more stable chemical properties than HgTe quantum dots.
[0081] (3) In this embodiment of the invention, a hole transport layer is introduced on a selenium-doped mercury telluride quantum dot layer, and CdTe quantum dot film is exchanged into HgTe small-sized quantum dot film by solid-phase cation exchange. This breaks through the size bottleneck of non-aqueous phase synthesis of HgTe quantum dots, so that there is a large electron affinity difference between the hole transport layer and the selenium-doped mercury telluride quantum dot layer, which reduces dark current and improves carrier separation efficiency, so that the photovoltaic device prepared by it has low dark current and high light response.
[0082] Please see Figure 3 , Figure 3 This is a schematic diagram of the structure of a selenium-doped mercury telluride quantum dot short-wave infrared detector provided in this application. The infrared detector includes: an electron transport layer, a selenium-doped mercury telluride quantum dot layer, and a hole transport layer. The selenium-doped mercury telluride quantum dot layer is located between the electron transport layer and the hole transport layer, and the electron transport layer, the selenium-doped mercury telluride quantum dot layer, and the hole transport layer form a p-on-n type junction. The hole transport layer is a HgTe quantum dot film, which is obtained by cation exchange between a CdTe quantum dot solution and a HgCl2 solution.
[0083] Furthermore, the infrared detector also includes: a substrate, a bottom electrode, and a top electrode. The bottom electrode is disposed on the substrate; the electron transport layer is disposed on the side of the bottom electrode away from the substrate; and the top electrode is disposed on the side of the hole transport layer away from the bottom electrode.
[0084] Specifically, the selenium-doped mercury telluride quantum dot short-wave infrared detector disclosed in this application comprises, from bottom to top: a substrate, a bottom electrode, an electron transport layer, a selenium-doped mercury telluride quantum dot layer, a hole transport layer, and a top electrode. The electron transport layer, the selenium-doped mercury telluride quantum dot layer, and the hole transport layer form a p-on-n junction. The bottom electrode and the top electrode are used to connect positive and negative charges, enabling current conduction. The hole transport layer is a HgTe quantum dot film, which is a small-sized HgTe quantum dot film prepared by cation exchange between a CdTe quantum dot solution and a HgCl2 solution. It possesses a large electron affinity difference with the selenium-doped mercury telluride quantum dot layer, reducing dark current while improving carrier separation efficiency, resulting in photovoltaic devices with low dark current and high light response. The substrate supports the bottom electrode, electron transport layer, selenium-doped mercury telluride quantum dot layer, hole transport layer, and top electrode.
[0085] The bottom electrode is indium tin oxide (ITO).
[0086] The electron transport layer is a Bi2S3 thin film. The thickness of the electron transport layer is 50-100 nm, with 80 nm being the optimal thickness.
[0087] The selenium-doped mercury telluride quantum dot layer is a Se:HgTe quantum dot with an absorption cutoff wavelength of 1500nm to 2500nm, and the thickness of the selenium-doped mercury telluride quantum dot layer is 400 to 500nm, with 450nm being the optimal thickness.
[0088] The hole transport layer has a thickness of 10–60 nm, with 35 nm being optimal.
[0089] The top electrode is an Au electrode. The thickness of the top electrode is 50–120 nm, with 100 nm being optimal.
[0090] The selenium-doped mercury telluride quantum dot infrared detector designed in this invention has good applications in the 1100–2500 nm short-wavelength detection field. Specifically, in the short-wavelength infrared field, the selenium-doped mercury telluride quantum dot infrared detector designed in this invention can penetrate windshields for imaging, thus it can be applied to automotive night vision systems to enhance night vision detection capabilities. It can also penetrate opaque plastics and silicon wafers, therefore it can be applied to non-destructive testing, material identification, etc.
[0091] The above description discloses only one preferred embodiment of the present invention, and should not be construed as limiting the scope of the present invention. Those skilled in the art will understand that all or part of the processes of the above embodiments can be implemented, and equivalent changes made in accordance with the claims of the present invention are still within the scope of the invention.
Claims
1. A method for fabricating a selenium-doped mercury telluride quantum dot short-wave infrared detector, characterized in that, The infrared detector includes an electron transport layer, a selenium-doped mercury telluride quantum dot layer, and a hole transport layer, wherein the electron transport layer, the selenium-doped mercury telluride quantum dot layer, and the hole transport layer form a p-on-n type junction. The method includes: A selenium-doped mercury telluride quantum dot layer is prepared on one side of the electron transport layer; Preparation of CdTe quantum dot solution; A CdTe quantum dot solution was spin-coated onto a selenium-doped mercury telluride quantum dot layer and then immersed in a HgCl2 solution to allow cation exchange between the CdTe quantum dot solution and the HgCl2 solution, thereby obtaining an HgTe quantum dot film and thus preparing a hole transport layer.
2. The preparation method according to claim 1, characterized in that, The method further includes: Provide a base; A bottom electrode is fabricated on the substrate; The electron transport layer is fabricated on the side of the bottom electrode away from the substrate; wherein the selenium-doped mercury telluride quantum dot layer is disposed on the side of the electron transport layer away from the bottom electrode; A top electrode is fabricated on the side of the hole transport layer away from the bottom electrode.
3. The preparation method according to claim 1, characterized in that, Preparation of CdTe quantum dot solution includes: Cadmium chloride powder is dissolved in oleylamine solution to form a cadmium precursor solution; Tellurium oxide and dodecyl mercaptan (DDT) are heated and stirred at a preset temperature to form a tellurium precursor solution; The cadmium precursor solution and the tellurium precursor solution were mixed to synthesize a CdTe quantum dot solution.
4. The preparation method according to claim 1, characterized in that, A CdTe quantum dot solution is spin-coated onto a selenium-doped mercury telluride quantum dot layer, and then immersed in HgCl2 solution to allow cation exchange between the CdTe quantum dot solution and the HgCl2 solution, thereby obtaining an HgTe quantum dot film and preparing a hole transport layer, comprising: A CdTe quantum dot solution was spin-coated onto a selenium-doped mercury telluride quantum dot layer; The solution is soaked in a methanol solution of HgCl2, which allows the cations Cd in the CdTe quantum dot solution to exchange with the cations Hg in the methanol solution of HgCl2. Solid-phase ligand exchange was performed using an ethanol solution of 1,2-ethylenedithiol, followed by solvent washing to remove residual ligands, resulting in an HgTe quantum dot film, thereby preparing the hole transport layer.
5. The preparation method according to claim 1, characterized in that, A selenium-doped mercury telluride quantum dot layer is fabricated on one side of the electron transport layer, comprising: Selenurea powder was dissolved in oleylamine solution and heated under nitrogen to obtain oleylamine-selenourea solution; The oleylamine selenide solution was mixed with the tri-n-octylphosphine telluride solution to obtain the selenium-doped mercury telluride precursor solution. A selenium-doped mercury telluride precursor solution was added to an oleylamine solution in which HgCl2 was dissolved to synthesize a selenium-doped mercury telluride quantum dot solution. A selenium-doped mercury telluride quantum dot solution was spin-coated onto one side of the electron transport layer to prepare a selenium-doped mercury telluride quantum dot layer.
6. The preparation method according to claim 1, characterized in that, The electron transport layer has a thickness of 50–100 nm.
7. The preparation method according to claim 4 or 5, characterized in that, The selenium-doped mercury telluride quantum dot solution is concentrated during spin coating, and the concentration is 1 to 1.5 times that of the selenium-doped mercury telluride quantum dot solution. The CdTe quantum dot solution is diluted during spin coating, and the dilution is 2 to 6 times that of the CdTe quantum dot solution.
8. The preparation method according to claim 1, characterized in that, The thickness of the selenium-doped mercury telluride quantum dot layer is 400–500 nm, and the thickness of the hole transport layer is 10–60 nm.
9. A selenium-doped mercury telluride quantum dot short-wave infrared detector, characterized in that, The infrared detector includes an electron transport layer, a selenium-doped mercury telluride quantum dot layer, and a hole transport layer. The selenium-doped mercury telluride quantum dot layer is located between the electron transport layer and the hole transport layer, and the electron transport layer, the selenium-doped mercury telluride quantum dot layer, and the hole transport layer form a p-on-n type junction. The hole transport layer is an HgTe quantum dot film, which is obtained by cation exchange between a CdTe quantum dot solution and an HgCl2 solution.
10. The selenium-doped mercury telluride quantum dot short-wave infrared detector according to claim 9, characterized in that, The infrared detector also includes: Base; A bottom electrode is disposed on the substrate; wherein the electron transport layer is disposed on the side of the bottom electrode away from the substrate; The top electrode is disposed on the side of the hole transport layer away from the bottom electrode.