Infrared absorbing material based on doping regulation and control, preparation method and infrared detector

Abstract

The invention provides an infrared absorption material based on doping regulation and control, a preparation method and an infrared detector, selenium atoms are introduced into a sodium gallium telluride material to replace tellurium atoms, doping is carried out according to the atomic weight doping proportion of 1: 4 to 1: 2, and the energy band structure and optical characteristics of the material are regulated and controlled to obtain a new infrared absorption material. The light absorption performance in an infrared band is obviously improved. Aiming at the component characteristics of the infrared absorption material, a targeted preparation scheme is provided, the preparation is completed by grinding, secondary melting and annealing treatment on the sodium elementary substance, the gallium elementary substance, the tellurium elementary substance and the selenium elementary substance with set principle mass, the band gap and the absorption intensity are accurately adjusted, and the symmetry and the crystal stability of the material are also considered.

Description

Technical Field

[0001] The present invention relates to the technical field of infrared absorption materials, and particularly to an infrared absorption material based on doping regulation, a preparation method thereof, and an infrared detector. Background Art

[0002] The absorption performance of existing infrared absorption materials in the short-wave infrared band (1–3 μm) is still insufficient, mainly restricted by multiple factors such as material bandgap matching, absorption efficiency, and crystal defects. The energy of short-wave infrared photons is relatively high (about 0.41–1.24 eV), requiring the absorption material to have a moderate bandgap and excellent optoelectronic conversion efficiency. However, existing materials still face challenges in practical applications. For example, HgCdTe has good bandgap tunability and absorption performance in the short-wave infrared band, but its thermal stability is poor, and the preparation difficulty is high; InGaAs is an important material in the short-wave infrared field, but its absorption wavelength is limited by the bandgap, usually unable to cover the entire short-wave infrared band, and the dark current of its devices is relatively high. In addition, crystal defects and surface state problems significantly affect the quantum efficiency and signal-to-noise ratio performance of existing short-wave infrared materials. At the same time, the thermal effect of high-energy photons also poses higher requirements for the stability of detectors. Summary of the Invention

[0003] In view of this, embodiments of the present invention provide an infrared absorption material based on doping regulation, a preparation method thereof, and an infrared detector to eliminate or improve one or more defects existing in the prior art and solve the problem of insufficient absorption performance of infrared absorption materials in the short-wave infrared band in the prior art.

[0004] One aspect of the present invention provides an infrared absorption material based on doping regulation, which uses sodium gallium telluride as the base material and uniformly introduces selenium atom doping, and the doping ratio of selenium to tellurium is 1:4 to 1:2 according to atomic weight.

[0005] On the other hand, the present invention also provides a preparation method of an infrared absorption material, which is used to prepare the above-mentioned infrared absorption material based on doping regulation, and the method includes the following steps:

[0006] Calculate the raw material masses of sodium, gallium, tellurium, and selenium required according to a preset doping ratio; wherein, the doping ratio of selenium to tellurium is 1:4 to 1:2 according to atomic weight;

[0007] Obtain the sodium, gallium, tellurium, and selenium of the corresponding raw material masses, place them in an agate mortar, grind and mix them under the protection of an inert gas, and load the mixed sodium, gallium, tellurium, and selenium into an ampoule tube and evacuate it;

[0008] Place the ampoule tube in a tube furnace for the first melting, and the first melting includes: heating to 950 °C at a heating rate of 5 °C / min and holding for 12 hours; cooling to 650 °C at a cooling rate of 10 °C / h to control the slow growth of crystals; finally, cooling to room temperature at a cooling rate of 5 °C / h to obtain a preliminary crystal material;

[0009] Take out the preliminary crystal material, grind it into powder again, refill it into the ampoule tube and place it in the tube furnace for the second melting, and the steps of the second melting are the same as those of the first melting;

[0010] Place the ampoule tube in the tube furnace, heat it to 400 °C, and hold for 12 hours to complete the annealing treatment to obtain the infrared absorption material.

[0011] In some embodiments, in the method, selenium and tellurium are doped according to a doping ratio of 1:4 by atomic weight, and the mass ratio of the sodium element, the gallium element, the tellurium element and the selenium element is 1:1:6:2.

[0012] In some embodiments, in the method, selenium and tellurium are doped according to a doping ratio of 1:2 by atomic weight, and the mass ratio of the sodium element, the gallium element, the tellurium element and the selenium element is 1:1:4:4.

[0013] In some embodiments, after mixing the sodium element, the gallium element, the tellurium element and the selenium element, they are filled into an ampoule tube and evacuated to at least 10 -4 Torr.

[0014] In some embodiments, the method further includes: using a planetary ball mill to grind the sodium element, the gallium element, the tellurium element, the selenium element or the preliminary crystal material to a particle size of less than 10 μm, and the planetary ball mill uses tungsten carbide balls.

[0015] In some embodiments, the planetary ball mill adopts a form of segmented intermittent grinding, grinding for 15 minutes each time and with an interval of 5 minutes.

[0016] In some embodiments, during the grinding and mixing process under the protection of an inert gas, the inert gas is argon; or, the inert gas is a mixed gas of 95% argon and 5% hydrogen.

[0017] In some embodiments, before filling the mixed sodium element, gallium element, tellurium element and selenium element into an ampoule tube and evacuating it, the method further includes: drying the ampoule tube at a temperature of 150 °C for 2 hours to remove moisture.

[0018] On the other hand, the present invention also provides an infrared detector, which uses the infrared absorption material prepared by the above-mentioned preparation method of infrared absorption material to detect infrared light.

[0019] The beneficial effects of the present invention are at least as follows:

[0020] For the infrared absorption material, preparation method and infrared detector based on doping regulation of the present invention, by introducing selenium atoms to replace tellurium atoms in the sodium gallium telluride material and doping according to the doping ratio of atomic weight from 1:4 to 1:2, the energy band structure and optical properties of the material are regulated to obtain a new infrared absorption material, significantly improving its light absorption performance in the infrared band. A targeted preparation scheme is provided according to the component characteristics of this infrared absorption material. The preparation is completed by grinding, secondary melting and annealing treatment of sodium, gallium, tellurium and selenium simple substances with set theoretical masses, not only accurately adjusting the band gap and absorption intensity, but also taking into account the symmetry and crystal stability of the material.

[0021] The additional advantages, objects, and features of the present invention will be partially described below, and will become partially apparent to those of ordinary skill in the art after studying the following text, or can be learned from the practice of the present invention. The objects and other advantages of the present invention can be realized and obtained by the structure specifically pointed out in the specification and the drawings.

[0022] Those skilled in the art will understand that the objects and advantages that can be achieved by the present invention are not limited to the above specifically described, and the above and other objects that the present invention can achieve will be more clearly understood according to the following detailed description. Description of the Drawings

[0023] The drawings described herein are used to provide a further understanding of the present invention, form a part of this application, and do not limit the present invention. In the drawings:

[0024] Figure 1 It is a schematic flow chart of the preparation method of the infrared absorption material according to an embodiment of the present invention.

[0025] Figure 2 is the original crystal structure diagram of NaGaTe 2 Original crystal structure diagram.

[0026] Figure 3 is the crystal structure diagram of NaGaTe after introducing selenium doping according to the atomic weight ratio of selenium to tellurium of 1:4 2 Crystal structure diagram.

[0027] Figure 4 is the crystal structure diagram of NaGaTe after introducing selenium doping according to the atomic weight ratio of selenium to tellurium of 1:2 2 Crystal structure diagram.

[0028] Figure 5 is NaGaTe 2 Absorption spectrum of the original crystal structure.

[0029] Figure 6 is NaGaTe 2 Inserted graph of the absorption spectrum of the original crystal structure.

[0030] Figure 7 is NaGaTe after introducing selenium doping according to the atomic weight ratio of selenium to tellurium of 1:4 2 Absorption spectrum of the crystal structure.

[0031] Figure 8 is NaGaTe after introducing selenium doping according to the atomic weight ratio of selenium to tellurium of 1:4 2 Inserted graph of the absorption spectrum of the crystal structure.

[0032] Figure 9 is NaGaTe after introducing selenium doping according to the atomic weight ratio of selenium to tellurium of 1:2 2 Absorption spectrum of the crystal structure.

[0033] Figure 10 is NaGaTe after introducing selenium doping according to the atomic weight ratio of selenium to tellurium of 1:2 2 Inserted graph of the absorption spectrum of the crystal structure. Detailed implementation manners

[0034] To make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below in conjunction with the implementation manners and the accompanying drawings. Herein, the illustrative implementation manners of the present invention and their descriptions are used to explain the present invention, but are not intended to limit the present invention.

[0035] Herein, it also needs to be noted that in order to avoid obscuring the present invention due to unnecessary details, only the structures and / or processing steps closely related to the solution according to the present invention are shown in the drawings, while other details less related to the present invention are omitted.

[0036] It should be emphasized that the term "including / containing" when used herein refers to the presence of features, elements, steps or components, but does not exclude the presence or addition of one or more other features, elements, steps or components.

[0037] Herein, it also needs to be noted that if not otherwise specified, the term "connection" in this article can not only refer to direct connection, but also represent indirect connection with an intermediate.

[0038] Currently, the absorption performance of infrared absorption materials in the short-wave infrared (SWIR, 1–3 μm) band still cannot fully meet the requirements of high-performance detectors and related optoelectronic devices. Due to its good spectral penetration and low scattering characteristics, the short-wave infrared band is widely used in fields such as near-earth observation, fiber optic communication, food quality detection, and biomedical imaging, which pose requirements for high sensitivity, high quantum efficiency, low dark current, and wide spectral response of infrared absorption materials. However, currently used short-wave infrared absorption materials still face some challenges. For example, InGaAs detectors are the mainstream materials in this band, but their spectral response range is usually limited within 1.7 μm, making it difficult to cover the entire short-wave infrared range; although silicon-based materials have good integration capabilities, their large bandgap and low absorption efficiency limit their application in the short-wave infrared band. In addition, problems such as crystal defects, interface states, and surface recombination in material preparation have a significant impact on absorption efficiency and device performance. At the same time, the thermal effect caused by high-energy short-wave infrared photons also poses higher requirements for the stability of the device. Although some new short-wave infrared materials have emerged in recent years, such as two-dimensional materials based on transition metal dichalcogenides (TMDs) and new quantum dot materials (such as PbS and PbSe quantum dots), these materials show certain advantages in response range and integration potential, but their large-scale preparation and long-term stability problems have not been fully solved. Therefore, developing new infrared absorption materials with excellent short-wave infrared absorption ability is an important direction to promote the development of this field.

[0039] The present invention aims to provide an optimized design method for infrared absorption materials based on doping regulation, by introducing selenium (Se) atom doping into sodium gallium telluride (NaGaTe 2 ) materials to reasonably regulate the energy band structure and optical properties of the materials. The electronegativity and atomic radius of selenium atoms are close to those of tellurium atoms, but the energy level distribution is slightly higher than that of tellurium atoms. By replacing some tellurium atom positions, selenium doping will introduce new electronic states or adjust the distribution of existing electronic states, resulting in a narrowing of the energy band gap (bandgap) or the generation of additional local energy levels, thereby enhancing the interaction between long-wave infrared photons and the material. In addition, selenium doping can improve the carrier concentration and mobility, optimize the optoelectronic response characteristics of the material, and at the same time fine-tune the lattice structure to reduce non-radiative recombination losses and further improve the absorption efficiency. This regulation method significantly improves the absorption performance of NaGaTe 2 materials in the infrared band, which helps to expand their applications in optoelectronic detection and energy conversion and other fields.

[0040] Specifically, one aspect of the present invention provides an infrared absorption material based on doping regulation. The material uses sodium gallium telluride as the base material and uniformly introduces selenium atom doping. The doping ratio of selenium to tellurium is 1:4 to 1:2 according to atomic weight. NaGaTe 2The original crystal structure diagram is as shown in Figure 2 . The crystal structure diagrams after doping according to the atomic weight ratio of selenium to tellurium of 1:4 or 1:2 are as shown in Figure 3 and Figure 4 .

[0041] Exemplarily, the doping ratio of 1:4 means that originally there were 8 tellurium atoms, and 2 selenium atoms replaced 2 original tellurium atoms. Now there are 2 selenium atoms and 6 tellurium atoms, and the total number of atoms is still 8. 2:8 is 1:4 (the number of selenium atoms: the number of selenium and tellurium atoms).

[0042] It should be emphasized here that in this embodiment, it is necessary to ensure that the doped atoms are evenly distributed and the crystal symmetry is maintained as much as possible. This is to optimize the performance of the material and at the same time reduce the adverse effects of structural mismatch and defects on the optoelectronic properties of the material. The specific reasons are as follows: (1) Reducing local defect states and non-radiative recombination centers: If the doped atoms are unevenly distributed, it will lead to the formation of doping clusters or defects with too high concentration in local areas. These defects may introduce deep energy levels in the band gap, thus forming non-radiative recombination centers, resulting in an increase in the recombination efficiency of photo-generated carriers and a decrease in the optoelectronic conversion efficiency of the material. Evenly distributing the doped atoms helps to reduce the formation of deep energy levels and improve the optoelectronic performance. (2) Maintaining the integrity and symmetry of the crystal structure: NaGaTe 2 is a crystal material, and its symmetry has an important influence on the energy band structure. If the doped atoms are unevenly distributed or the crystal symmetry is destroyed, it may lead to lattice distortion, local stress concentration or symmetry reduction, which will cause distortion of the energy band structure or non-uniform change of the band gap, thus reducing the light absorption performance of the material in the infrared band. Maintaining the crystal symmetry can ensure stable energy band characteristics and is beneficial to infrared light absorption. (3) Optimizing the carrier transport performance: Evenly distributing the doped atoms helps to avoid too high local charge concentration or potential distortion, thus reducing charge scattering and improving the mobility and diffusion length of carriers. High mobility is crucial for improving the optoelectronic conversion efficiency and response speed of the material. (4) Enhancing the thermodynamic stability of the material: Evenly distributed doped atoms can reduce the stress and energy gradient in local areas of the crystal, thus improving the thermodynamic stability of the material and reducing the performance degradation caused by hot carriers or long-term use. This is particularly important for applications such as infrared detectors that need to work under harsh conditions for a long time. (5) Ensuring macroscopic performance consistency: In practical applications, the material usually needs to be fabricated into large-area or thin-film devices. Evenly distributing the doped atoms can ensure that the macroscopic performance of the material is consistent throughout the sample range, avoiding device functional failure or deviation caused by local performance differences.

[0043] The present invention also provides a preparation method of an infrared absorption material, and the method is used to prepare the above-mentioned infrared absorption material based on doping regulation, as shown in Figure 1 . The method includes the following steps S101 to S105:

[0044] Step S101: Calculate the raw material masses of sodium, gallium, tellurium, and selenium required according to a preset doping ratio; among them, the doping ratio of selenium to tellurium is from 1:4 to 1:2 according to atomic weights.

[0045] Step S102: Obtain sodium, gallium, tellurium, and selenium with corresponding raw material masses, place them in an agate mortar, grind and mix them under the protection of an inert gas, and load the mixed sodium, gallium, tellurium, and selenium into an ampoule tube and evacuate it.

[0046] Step S103: Place the ampoule tube in a tube furnace for the first melting. The first melting includes: heating to 950 °C at a heating rate of 5 °C / min and holding for 12 hours; cooling to 650 °C at a cooling rate of 10 °C / h to control the slow growth of crystals; finally, cooling to room temperature at a cooling rate of 5 °C / h to obtain a preliminary crystal material.

[0047] Step S104: Take out the preliminary crystal material, grind it into powder again, reload it into the ampoule tube, and place it in the tube furnace for the second melting. The steps of the second melting are the same as those of the first melting.

[0048] Step S105: Place the ampoule tube in the tube furnace, heat it to 400 °C, and hold for 12 hours to complete the annealing treatment to obtain an infrared absorption material.

[0049] In step S101, the doping is carried out at a doping ratio of selenium to tellurium of 1:4 according to atomic weights, and the mass ratio of sodium, gallium, tellurium, and selenium is 1:1:6:2. In some other embodiments, the doping is carried out at a doping ratio of selenium to tellurium of 1:2 according to atomic weights, and the mass ratio of sodium, gallium, tellurium, and selenium is 1:1:4:4.

[0050] Exemplarily, in NaGaTe 2 the stoichiometric ratio of sodium (Na), gallium (Ga), and tellurium (Te) is 1:1:2. In the case of selenium doping, part of the tellurium is replaced by selenium, and the atomic number ratio of selenium to tellurium is 1:4. Therefore, after doping, the total atomic number of selenium and tellurium still satisfies the ratio constraint of Te 2

[0051] The atomic weight of sodium (Na) is 22.99 (about 23). The atomic weight of gallium (Ga) is 69.72 (about 70). The atomic weight of tellurium (Te) is 127.6 (about 128). The atomic weight of selenium (Se) is 78.96 (about 79).

[0052] ​The atomic number ratio of tellurium to selenium is 4:1. In the total doping ratio, there are 4 tellurium atoms and 1 selenium atom for every 5 atoms. The mass contribution ratio of tellurium to selenium is: 4×128 (atomic weight of tellurium) : 1×79 (atomic weight of selenium) = 512:79. This means that in the tellurium-selenium part, the mass fraction of tellurium is 512 / (512 + 79) ≈ 0.866, and the mass fraction of selenium is 79 / (512 + 79) ≈ 0.134.

[0053] For 1 NaGaTe 2 unit, the stoichiometric ratio is 1:1:2. After adding selenium doping: the number of atoms of sodium and gallium is 1 each, and the mass contributions are 23 and 70 respectively. The mass contributions of tellurium and selenium are calculated according to the above ratio, and the overall mass ratio can be written as: sodium:gallium:tellurium:selenium = 23:70:(2×128×0.866):(2×128×0.134). After simplification, sodium:gallium:tellurium:selenium ≈ 23:70:221:43. The ratio is approximated to an integer ratio of 1:1:6:2.

[0054] In step S102, use a high-precision electronic balance (accuracy 0.0001 g) to weigh the masses of sodium metal, gallium metal, tellurium metal, and selenium metal respectively. Ensure that the purity of the raw materials used meets the experimental requirements (usually ≥99.99%), to avoid the influence of impurities on the performance of the final material. Operate in a glove box protected by an inert gas (such as argon or high-purity nitrogen) or an isolated environment filled with an inert gas. The purity of the inert gas should reach 99.999%, ensuring that the oxygen and moisture content in the environment is extremely low (<1 ppm), to avoid the oxidation of active metals such as sodium metal or reaction with water.

[0055] In some embodiments, during the grinding and mixing process under the protection of an inert gas, the inert gas is argon; or, the inert gas is a mixed gas of 95% argon and 5% hydrogen.

[0056] Use an agate mortar and pestle that are chemically resistant and do not react with the raw materials. The agate material has good chemical inertness and mechanical stability, making it suitable for handling active materials. Place the weighed sodium, gallium, tellurium, and selenium elemental substances into the mortar in sequence, avoiding direct contact with sodium elemental substance (sodium should be mixed first). Use a uniform force application method to slowly grind, ensuring that the materials are evenly mixed while avoiding particle scattering or material waste caused by excessive force. Adjust the grinding time according to the required mixing degree, generally lasting 20 - 30 minutes, and regularly check the mixing uniformity during this period. During the grinding process, the mixing uniformity can be judged by observing the color, texture, and particle distribution state of the materials. If there are obvious particle agglomeration phenomena, extend the grinding time or appropriately adjust the grinding force. During the operation, sodium elemental substance has high activity and is extremely prone to reacting with oxygen and water. The operation needs to be carried out under the protection of an inert atmosphere throughout to avoid contact with air and moisture. There may be a risk of static charge accumulation in the materials, especially powdered selenium and tellurium. Wear anti-static gloves during the operation and ensure that the workbench is grounded. The operator needs to wear protective gloves, protective glasses, and anti-static laboratory clothing to avoid direct contact of the materials with the skin or scattering.

[0057] In some embodiments, the method uses a planetary ball mill to grind sodium elemental substance, gallium elemental substance, tellurium elemental substance, selenium elemental substance, or preliminary crystal materials to a particle size below 10 μm. The planetary ball mill uses tungsten carbide balls. The planetary ball mill adopts a form of segmented intermittent grinding, grinding for 15 minutes each time with a 5-minute interval.

[0058] In some embodiments, load the mixed sodium elemental substance, gallium elemental substance, tellurium elemental substance, and selenium elemental substance into an ampoule tube and evacuate it to at least 10 -4 Torr. Exemplarily, select a high-purity quartz ampoule tube with a smooth inner wall and no cracks. The size is selected according to the sample amount, generally with a diameter of 10 - 15 mm and a length of 15 - 20 cm. Equip a high-vacuum pump (such as a turbomolecular pump or a diffusion pump) and a vacuum gauge (such as an ionization vacuum gauge) to ensure that a vacuum degree below 10 -4 Torr can be achieved. Thoroughly clean the ampoule tube with anhydrous ethanol or acetone to remove dust and impurities. Dry the ampoule tube in an oven at 120°C - 150°C for at least 2 hours to ensure that there is no moisture on the inner wall. Operate in a glove box or an inert gas protection environment, keeping the oxygen and moisture content below <1 ppm.

[0059] Further, use a static-free funnel to transfer the well-mixed sodium, gallium, tellurium, and selenium mixture to the bottom of the ampoule tube. Ensure that the sample filling amount accounts for 1 / 3 to 1 / 2 of the total volume of the ampoule tube to avoid cracking due to thermal expansion during subsequent high-temperature treatment. The sample should be as close as possible to the bottom of the ampoule tube to prevent the sample from scattering on the tube wall. If the sample is in powder form, gently tap the outer wall of the ampoule tube to make the powder deposit tightly. Connect the open part of the ampoule tube to the vacuum system with a vacuum adapter, ensuring a good seal at the connection (vacuum grease or a sealing rubber ring can be used to enhance the sealing). Turn on the vacuum pump to start pumping, and close other openings of the ampoule tube to ensure no gas leakage. Start the preliminary pumping with a low vacuum pump (such as a mechanical pump) and continue pumping until it is less than 10 Torr. Switch to a high vacuum pump (such as a turbomolecular pump) and continue to pump vacuum until the vacuum degree reaches -4 below 10 Torr. During the vacuum pumping process, observe the reading of the vacuum gauge and check whether there is leakage at the connection of the ampoule tube (a small amount of high-purity nitrogen can be injected for testing). Maintain the vacuum state for 10 - 20 minutes to ensure the stability of the vacuum degree. If the vacuum degree continues to decrease, the leakage point needs to be checked and repaired.

[0060] Further, in a vacuum environment, adjust the height of the ampoule tube so that the sample is at the bottom of the tube and away from the heating area to prevent the high temperature during tube sealing from affecting the sample. Heat the open part of the ampoule tube with an oxy-acetylene flame or a hydrogen-oxygen flame, and rotate the ampoule tube evenly to ensure uniform heating. When the quartz softens to a highly plastic state at high temperature, use an appropriate tool to draw it thinner and seal the tube opening to form a stable vacuum seal point. During the cooling process, ensure that the sealed ampoule tube is placed upright to prevent the sample from moving due to vibration. After tube sealing, use a cooled vacuum gauge to detect whether there is air leakage at the sealed part. If the vacuum degree still meets the standard, the tube sealing is successful; if not, the tube needs to be sealed again.

[0061] In step S103, place the ampoule tube horizontally in the middle of the heating zone of the tube furnace, ensuring that it is in the position with the most uniform temperature. Use a high-temperature-resistant quartz bracket or a ceramic support to fix the ampoule tube to prevent the ampoule tube from moving during heating or cooling. Close the sealing covers at both ends of the tube furnace, and at the same time connect the inert gas input and the exhaust port to ensure that the gas can circulate. Adjust the flow rate of the inert gas (usually 50 - 100 mL / min), and flush the furnace tube with the inert gas for 10 - 15 minutes to remove the residual oxygen and moisture in the furnace tube.

[0062] Further, turn on the tube furnace and maintain the flow of inert gas throughout the heating process. Set the heating rate to 5 °C / min on the program controller of the tube furnace. The target temperature is 950 °C, and a segmented program is set to ensure a smooth temperature increase. During the heating period, regularly check the state of the sample inside the furnace tube to ensure that the ampoule tube has no cracks or abnormalities. When the temperature reaches 950 °C, keep the furnace temperature constant and start timing for heat preservation for 12 hours. During the heat preservation period, continue to maintain the flow of inert gas to protect the sample. During the cooling process, set the cooling rate to 10 °C / h and slowly cool down to 650 °C. This stage is the slow crystal growth stage. By controlling the cooling rate, the crystals inside the sample are promoted to be arranged orderly. When the temperature drops to 650 °C, adjust the cooling rate to 5 °C / h and continue to cool down to room temperature. During the cooling process, avoid external vibrations to prevent interference with crystal growth.

[0063] In step S104, taking out the preliminary crystal material, grinding it into powder again, reloading it into the ampoule tube and performing the second melting is mainly to improve the material uniformity. During the first melting process, due to compositional segregation, crystal growth defects or microscopic compositional non-uniformity in local areas, the performance of the material may be unstable. After grinding the crystal into uniform powder again, it is possible to remix the components in different regions, eliminate possible chemical non-uniformity, and provide a uniform starting material for the next crystal growth step. Moreover, the crystals formed after the first melting may contain microcracks, grain boundary defects or poor grain orientations, which will affect the optical, electrical or mechanical properties of the material. By melting again and slowly cooling down, the single crystal structure of the crystal can be further optimized or the grain orientation of the polycrystal can be improved, making the crystal quality inside the material more perfect. During the first melting process, there may be a small amount of impurities that are not fully removed (such as precursors that did not fully participate in the chemical reaction, gas inclusions, etc.). The high-temperature process of the second melting helps to further remove the impurities and make the material structure more pure and stable. During the first melting and cooling process, due to the difference in thermal expansion coefficients during crystal growth or improper control of the cooling rate, internal stress may be introduced. Grinding into powder again and melting can "reset" the material, eliminate the stress distribution left over from the first melting process, and ensure the structural stability of the final crystal material.

[0064] In this embodiment, the steps of the second melting are the same as those of the first melting.

[0065] In step S105, place the ampoule tube containing the sample in the middle position of the heating zone of the tube furnace to ensure that it is located in the area with the most uniform temperature. Fix the ampoule tube using a high-temperature resistant quartz bracket or ceramic bracket to prevent the ampoule tube from moving during the heating or cooling process. Connect the gas inlet and outlet of the tube furnace to ensure smooth gas flow. Turn on the flow of inert gas (such as argon), control the flow rate at 50 - 100 mL / min, and flush the furnace tube for 10 - 15 minutes to remove oxygen and moisture. Ensure that a stable inert gas protection environment is formed inside the furnace tube. Set the heating rate to 5 °C / min and the target temperature to 400 °C on the program controller of the tube furnace. During the heating process, regularly check the operating status of the temperature control system and ensure that the inert gas protection environment is stable and leak-free. When the temperature reaches 400 °C, keep it constant for 12 hours. Ensure that the furnace temperature fluctuation during the entire heat preservation stage does not exceed ±1 °C. Regularly check the furnace body status and the inert gas flow situation to prevent the sample from being contaminated due to gas interruption or equipment failure. After heat preservation for 12 hours, set the cooling program, control the cooling rate at 5 °C / min or lower until it reaches room temperature. Natural cooling or program-controlled cooling can be used to avoid thermal stress damage to the ampoule tube or impairment of material properties caused by rapid cooling. Keep the inert gas flowing during the cooling process until the furnace temperature drops to room temperature to ensure that the sample is not exposed to oxygen or moisture during the entire cooling process.

[0066] On the other hand, the present invention also provides an infrared detector, which uses the infrared absorption material prepared by the above-mentioned preparation method of the infrared absorption material to detect infrared light.

[0067] The present invention will be described below with specific embodiments:

[0068] This embodiment provides an optimized design method for infrared absorption materials based on doping regulation, by introducing Se atom doping into the NaGaTe 2 material to reasonably regulate the energy band structure and optical properties of the material, so as to significantly improve its light absorption performance in the infrared band. This embodiment can not only accurately adjust the band gap and absorption intensity, but also take into account the symmetry and crystal stability of the material, providing a new design idea for the development of high-performance infrared detector absorption materials.

[0069] This embodiment includes the following steps: First, use the NaGaTe 2 material as the substrate, and use first-principles calculations to evaluate its crystal structure, band gap, and optical properties; then, through the doping design of introducing Se atoms to replace Te atoms in the material, the doping ratio range is 1:4 to 1:2, ensuring that the doped atoms are evenly distributed and the crystal symmetry is maintained as much as possible; finally, optimize and evaluate the spectral characteristics of the materials with different doping ratios, combine experimental verification of the enhanced effect of the optical response, and determine the optimal doping concentration and material design scheme.

[0070] After doping with Se atoms, the internal electronic structure of the material can be changed. The electronegativity and electron orbital energy levels of Se atoms are different from those of Te atoms. Its doping causes a redistribution of the local energy band, adjusting the relative positions of the conduction band and the valence band. After doping with Se, due to its smaller atomic radius and higher orbital overlap, it leads to the reconstruction of chemical bonds and the local non-uniformity of charge distribution in the crystal, thus affecting the band gap width and the probability of optical transition. At the same time, doping triggers a change in the local density of states of the material, increasing the number of transition states in the infrared band and further enhancing the material's absorption ability of infrared light.

[0071] Regarding NaGa(Te 1-x Se x ) 2 The preparation of the crystal includes the following steps 1 to 6:

[0072] 1. Raw material selection and ratio

[0073] First, select high-purity (≥99.99%) Na, Ga, Te, and Se elemental substances as raw materials. Calculate the mass of each raw material according to the target stoichiometric ratio. The doping ratios are simulated as 1:4 and 1:2. When the doping ratio is 1:4, the ratio of Na:Ga:Te:Se is 1:1:6:2; when the doping ratio is 1:2, the ratio of Na:Ga:Te:Se is 1:1:4:4.

[0074] 2. Raw material mixing and encapsulation

[0075] Place the weighed Na, Ga, Te, and Se raw materials in an agate mortar, grind and mix them under the protection of an inert atmosphere (such as argon) to ensure the uniform distribution of each raw material. Subsequently, load the mixed raw materials into a clean and dry high-purity quartz ampoule tube, evacuate to better than 10 -4 Torr to avoid oxidation and impurity contamination. Seal the ampoule tube under vacuum conditions to ensure good airtightness during the subsequent heating process.

[0076] 3. Melting and crystal growth

[0077] Place the sealed ampoule tube in a tube furnace for melting treatment. The heating program is: heat to 950 °C at a heating rate of 5 °C / min, hold for 12 hours to ensure that the raw materials are fully melted and uniformly mixed; then, cool to 650 °C at a cooling rate of 10 °C / h to control the slow growth of the crystal; finally, cool to room temperature at a cooling rate of 5 °C / h to obtain the preliminary crystal material.

[0078] 4. Optimization of doping uniformity

[0079] After the cooled crystal material is taken out, it is ground into powder and mixed evenly, and then reloaded into an ampoule tube for secondary melting treatment. This step aims to further improve the uniform distribution of doped atoms in the crystal and ensure better structural uniformity and consistency of the material.

[0080] 5. Annealing Treatment

[0081] The treated material is placed in a tube furnace, heated to 400 °C, and annealed for 12 hours. This annealing process helps to optimize the integrity of the crystal structure, reduce the internal stress of the material, and thus improve the overall performance and stability of the material.

[0082] 6. Performance Characterization

[0083] To verify the performance of the material, the phase composition of the doped crystal and the integrity of the crystal structure are confirmed by X-ray diffraction (XRD) technology; the uniformity of Se atom distribution in the material is analyzed using scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS); in addition, the optical absorption performance of the material is measured using a UV-Vis-NIR spectrophotometer, and the improvement effect of the infrared absorption performance is verified in combination with the first-principles calculation results.

[0084] In this example, through doping regulation, not only a reasonable adjustment of the bandgap is achieved, but also the light absorption performance is significantly enhanced in the infrared band, showing a high directional selectivity response. In addition, this method combines theoretical calculation and experimental verification to ensure the efficiency of the design process and the feasibility of the material, providing a practical technical route for the development of infrared detection materials.

[0085] NaGaTe 2 The absorption spectra of the original crystal structure and its inset are Figure 5 and 6 , and for NaGaTe doped with selenium with a selenium-to-tellurium atomic weight ratio of 1:4 2 the absorption spectra of the crystal structure and its inset are Figure 7 and 8 , and for NaGaTe doped with selenium with a selenium-to-tellurium atomic weight ratio of 1:2 2 the absorption spectra of the crystal structure and its inset are Figure 9 and 10 . By comparing the absorption spectra before and after doping regulation (see Figure 5-10 ), it can be clearly seen that the absorption intensity of the material in the infrared band range has been significantly improved, especially showing enhanced absorption responses in multiple directions (such as XX, YY, ZZ). This improvement effect indicates that the introduction of Se atoms effectively optimizes the optical properties of the material, enhances the material's response ability to infrared light by adjusting the bandgap and electronic structure, and provides an important theoretical basis and technical support for the design and application of infrared absorption materials.

[0086] In summary, for the infrared absorption material, preparation method and infrared detector based on doping regulation according to the present invention, by introducing selenium atoms to replace tellurium atoms in the sodium gallium telluride material and doping according to the doping ratio of 1:4 to 1:2 by atomic weight, the energy band structure and optical properties of the material are regulated to obtain a new infrared absorption material, significantly improving its light absorption performance in the infrared band. A targeted preparation scheme is provided for the component characteristics of this infrared absorption material. The preparation is completed by grinding, secondary melting and annealing of sodium, gallium, tellurium and selenium in the set theoretical mass, not only precisely adjusting the band gap and absorption intensity, but also taking into account the symmetry and crystal stability of the material.

[0087] Those of ordinary skill in the art should understand that the various exemplary components, systems and methods described in connection with the embodiments disclosed herein can be implemented in hardware, software, or a combination of both. Specifically, whether to implement in hardware or software depends on the specific application and design constraints of the technical solution. A professional technician can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of the present invention. When implemented in hardware, it can be, for example, an electronic circuit, an application specific integrated circuit (ASIC), appropriate firmware, a plug-in, a functional card, etc. When implemented in software, the elements of the present invention are programs or code segments for performing the required tasks. The program or code segment can be stored in a machine-readable medium, or transmitted through a data signal carried in a carrier wave on a transmission medium or a communication link.

[0088] It should be clear that the present invention is not limited to the specific configurations and processes described above and shown in the figures. For the sake of brevity, detailed descriptions of known methods are omitted here. In the above embodiments, several specific steps are described and shown as examples. However, the method process of the present invention is not limited to the specific steps described and shown. Those skilled in the art can make various changes, modifications and additions, or change the order between steps after understanding the spirit of the present invention.

[0089] In the present invention, the features described and / or illustrated for one embodiment can be used in the same or similar manner in one or more other embodiments, and / or combined with the features of other embodiments or replace the features of other embodiments.

[0090] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, various changes and modifications can be made to the embodiments of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. An infrared absorbing material based on doping regulation, characterized in that: The material is based on sodium gallium telluride, and selenium atoms are uniformly introduced for doping. Selenium and tellurium are doped at a doping ratio of 1:4 to 1:2 in atomic weight.

2. A method for preparing an infrared absorbing material, characterized in that: The method is used to prepare the infrared absorption material based on doping regulation according to claim 1, and the method comprises the following steps: According to the preset doping ratio, the raw material masses of the required sodium element, gallium element, tellurium element and selenium element are calculated; wherein the doping ratio of selenium to tellurium is 1:4 to 1:2 according to the atomic weight; Obtaining the sodium element, the gallium element, the tellurium element and the selenium element of corresponding raw material mass, placing them in an agate mortar, grinding and mixing them under the protection of an inert gas, and placing the mixed sodium element, the gallium element, the tellurium element and the selenium element into an ampoule tube and evacuating the tube; The ampoule tube is placed in a tube furnace for the first melting, wherein the first melting includes: heating to 950°C at a heating rate of 5°C / min and keeping the temperature for 12 hours; cooling to 650°C at a cooling rate of 10°C / h to control the slow growth of crystals; and finally cooling to room temperature at a cooling rate of 5°C / h to obtain a preliminary crystal material; Taking out the preliminary crystal material, grinding it into powder again, reloading it into the ampoule tube and placing it in the tube furnace for a second melting, wherein the steps of the second melting are the same as those of the first melting; The ampoule tube is placed in the tube furnace, the temperature is raised to 400° C., and the temperature is kept for 12 hours to complete the annealing treatment, thereby obtaining the infrared absorbing material.

3. The method for preparing the infrared absorbing material according to claim 2, characterized in that: In the method, selenium and tellurium are doped at a doping ratio of 1:4 in atomic weight, and the mass ratio of the sodium element, the gallium element, the tellurium element and the selenium element is 1:1:6:

2.

4. The method for preparing the infrared absorbing material according to claim 2, characterized in that: In the method, selenium and tellurium are doped at a doping ratio of 1:2 in atomic weight, and the mass ratio of the sodium element, the gallium element, the tellurium element and the selenium element is 1:1:4:

4.

5. The method for preparing the infrared absorbing material according to claim 2, characterized in that: The mixed sodium, gallium, tellurium and selenium are placed in an ampoule tube and evacuated to a vacuum of at least 10 -4 Torr.

6. The method for preparing the infrared absorbing material according to claim 2, characterized in that: The method further includes: grinding the sodium element, the gallium element, the tellurium element, the selenium element or the preliminary crystalline material to a particle size of less than 10 μm using a planetary ball mill, wherein the planetary ball mill uses tungsten carbide balls.

7. The method for preparing the infrared absorbing material according to claim 6, characterized in that: The planetary ball mill adopts segmented interval grinding, with each grinding lasting 15 minutes and an interval of 5 minutes.

8. The method for preparing the infrared absorbing material according to claim 2, characterized in that: During the grinding and mixing process under the protection of an inert gas, the inert gas is argon; or, the inert gas is a mixed gas of 95% argon and 5% hydrogen.

9. The method for preparing the infrared absorbing material according to claim 2, characterized in that: Before the mixed sodium element, gallium element, tellurium element and selenium element are loaded into an ampoule tube and evacuated, the method further comprises: drying the ampoule tube at a temperature of 150° C. for 2 hours to remove moisture.

10. An infrared detector, characterized in that: The infrared detector detects infrared light using an infrared absorption material prepared by the method for preparing an infrared absorption material according to any one of claims 2 to 9.

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