PbSe infrared detection film and preparation method thereof and infrared detector

Abstract

The present invention discloses a PbSe infrared detection film, a preparation method thereof, and an infrared detector. The preparation method of the PbSe infrared detection film comprises: depositing a PbSe film on a substrate by physical vapor deposition using a pre-sensitized target material. The pre-sensitized target material is doped with oxidizing elements by pre-sensitization, and then a sensitized PbSe film with uniform element distribution can be directly prepared on various substrates by further physical vapor deposition, thereby eliminating the need for a high-temperature sensitization step, thereby avoiding element segregation caused by a high-temperature process. At the same time, it also overcomes the defect of being unable to be applied to substrates such as flexible organic materials due to high-temperature limitations, and facilitates compatibility with modern electronic manufacturing technology. Therefore, the preparation method of the PbSe infrared detection film simplifies the preparation process of the PbSe infrared detector, greatly reduces the cost, and provides the possibility for PbSe to be applied to large-area, high-precision, flexible, wearable infrared detectors.

Description

Technical Field

[0001] The present invention relates to the field of photoelectric detection technology, and in particular to a PbSe infrared detection film, a preparation method thereof, and an infrared detector. Background Art

[0002] With advances in photoelectric detection technology, infrared detectors have evolved from the original single-pixel detectors to the fourth generation of focal plane infrared detectors. Photoconductive infrared detectors, based on the internal photoelectric effect, have high response rates and sensitivity, enabling rapid and accurate infrared detection of distant targets. They are widely used in military and civilian applications such as missile guidance, fire control and aiming, night vision enhancement, security monitoring, and forest fire prevention. However, precisely due to the limitations of the photoelectric effect, the excellent performance of most photoconductive infrared detectors can only be guaranteed at low temperatures. When operating at ambient temperature, the detectors require additional cooling systems, which significantly increases the size, weight, and manufacturing cost of the detectors, thereby limiting the application of photon infrared detectors in the civilian market.

[0003] Lead selenide (PbSe) exhibits excellent room-temperature infrared detection capabilities in the mid-infrared range of 1 to 5 μm due to its suitable bandgap, large effective carrier mass, low carrier mobility, low Auger recombination coefficient, and direct bandgap structure. It is an important material for the fabrication of low-cost, high-performance, room-temperature, uncooled photoconductive infrared detectors. Notably, initially prepared PbSe thin films lack infrared photosensitivity and must undergo a high-temperature process in an oxidizing atmosphere to achieve a good response to infrared radiation. This process is known as PbSe sensitization. However, the readily dissociable nature of the Se element in selenide causes the release of Se vapor during sensitization at high temperatures. This shifts the stoichiometric ratio of Pb to Se in the film from 1:1, increasing the Se vacancy density in the PbSe film, hindering carrier transport and directly affecting the film's infrared detection performance. In addition, the high-temperature sensitization process after the film preparation is completed greatly limits the range of choices for PbSe film substrate materials, so that it can only be prepared on high-temperature resistant inorganic materials such as Si, SiO2, quartz, and glass. This restricts its integration with components and industrial chains such as IC circuits and infrared focal plane imaging chips, and limits the rapid development of PbSe infrared detectors.

[0004] In view of this, the present invention is proposed. Summary of the Invention

[0005] The purpose of the present invention is to provide a PbSe infrared detection film and its preparation method and infrared detector to improve the problem of element segregation of PbSe film at high temperature, high temperature restriction of substrate type selection and compatibility with modern electronic manufacturing technology.

[0006] The present invention is achieved in that:

[0007] In a first aspect, the present invention provides a method for preparing a PbSe infrared detection film, which comprises: depositing a PbSe film on a substrate by physical vapor deposition using a pre-sensitized target.

[0008] In a second aspect, the present invention further provides a PbSe infrared detection film, which is prepared by the above-mentioned preparation method of the PbSe infrared detection film.

[0009] In a third aspect, the present invention further provides an infrared detector comprising the above-mentioned PbSe infrared detection film.

[0010] The present invention has the following beneficial effects: a PbSe thin film is prepared by physical vapor deposition using a pre-sensitized target material, that is, the pre-sensitized target material is doped with an oxidizing element by pre-sensitization, and then a sensitized PbSe thin film with uniform element distribution can be directly prepared on various substrates by physical vapor deposition, thereby eliminating the need for a high-temperature sensitization step, thereby avoiding element segregation caused by a high-temperature process, and also overcoming the defect of being unable to be applied to substrates such as flexible organic materials due to high-temperature limitations, thereby facilitating compatibility with modern electronic manufacturing technology. Therefore, the preparation method of the PbSe infrared detection thin film simplifies the preparation process of the PbSe infrared detector relative to the traditional high-temperature sensitization process, greatly reduces the cost, and provides the possibility for PbSe to be applied to large-area, high-precision, flexible wearable infrared detectors. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0012] Figure 1 XRD patterns of the PbSe infrared detection films obtained in Example 1 and Example 2 of the present invention and Comparative Examples 1 and 2;

[0013] Figure 2 This is a schematic structural diagram of an infrared detector according to a test example of the present invention;

[0014] Figure 3 Graph showing the current changes of infrared detectors corresponding to the PbSe infrared detection films obtained in Example 1 and Example 2 of the present invention and Comparative Examples 1 and 2 in response to square wave pulse infrared radiation;

[0015] Figure 4This is the XRD pattern of the PbSe infrared detection film obtained in Inventive Example 5;

[0016] Figure 5 This is a photocurrent variation diagram of the PbSe infrared detection film obtained in Inventive Example 5;

[0017] Figure 6 This is a comparison of the surface morphologies of PbSe infrared detection films prepared at different evaporation powers obtained in Example 6 of the invention. DETAILED DESCRIPTION

[0018] To make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are described clearly and completely below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer are used. Where the manufacturer of the reagents or instruments is not specified, they are all conventional products that can be purchased commercially.

[0019] The following is a detailed description of a PbSe infrared detection film, a preparation method thereof, and an infrared detector provided by the present invention.

[0020] Some embodiments of the present invention provide a method for preparing a PbSe infrared detection film, which comprises: depositing a PbSe film on a substrate by physical vapor deposition using a pre-sensitized target.

[0021] At present, there is still controversy in the academic community about the key sensitizing elements and the PbSe photoconductive detection mechanism. It is generally believed that the high-temperature sensitization process is related to the crystallization quality, band gap structure, oxidation state control, etc. of the PbSe film. On this basis, the inventors have found through research and practice that the high-temperature sensitization step is not a necessary step. By advancing the sensitization process, that is, pre-sensitizing the target material before physical vapor deposition, there is no need to perform high-temperature treatment on the PbSe film after physical vapor deposition. The infrared detection performance of the PbSe film obtained by this method can reach a level comparable to that of the PbSe film obtained by traditional high-temperature sensitization treatment. The above preparation method of the embodiment of the present invention effectively avoids the high-temperature process after the film preparation is completed, that is, avoids the element segregation caused by the high-temperature process, and also overcomes the defect that it cannot be placed on substrates such as flexible organic materials due to high-temperature limitations, making it compatible with modern electronic manufacturing technology.

[0022] It should be noted that the key to the above embodiments of the present invention is to use a presensitized target material for physical vapor deposition, that is, the source and formation method of the presensitized target material are not limited. As long as the presensitization of the target material can be achieved by certain existing means, it can be used.

[0023] Specifically, in some embodiments, the presensitized target is obtained by any of the following methods:

[0024] (1) Add one or more oxygen-containing element compound powders into the target material.

[0025] In some embodiments, the method of incorporating the compound powder includes, but is not limited to, mechanical stirring, airflow mixing, or liquid mixing, as long as uniform mixing of the compound powder and the target material is achieved. Uniform dispersion of the compound powder in the target material can result in a uniform distribution of various elements in the thin film formed by physical vapor deposition.

[0026] In some embodiments, the added compound powder includes, but is not limited to, one or a combination of two or more of PbO, PbO2, SeO2, PbS, and PbI2. For example, the added compound powder may be PbO, PbO2, SeO, or PbI2, or a mixture of PbO and PbI2.

[0027] The proportion of the incorporated compound powder will affect the properties of the final PbSe film to a certain extent. Therefore, in some embodiments, the incorporated atomic ratio is 0.1% to 30%, for example, the incorporated atomic ratio is 0.1%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 8%, 8.5%, 9%, 9.5%, 10%, 10.5%, 11%, 11.5%, 12%, 12.5%, 13%, 13.5%, 14%, 14.5%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29% or 30%, etc. It is preferably 9.5%, 10% or 10.5%, and more preferably 10%.

[0028] In some embodiments, the homogeneous mixture of the target material and the compound powder is pressed into a tablet to obtain a presensitized target.

[0029] It should be noted that, in order to uniformly mix the compound powder and the target material, in some embodiments, the target material is PbSe powder.

[0030] (2) Annealing the target in an oxidizing atmosphere.

[0031] Specifically, in some embodiments, the powdered target material is first annealed in an oxidizing atmosphere. Generally, after annealing, it is then ground to uniformly mix the elements. The target material is then pressed into tablets. By processing the powdered target material, it is easier to dope and sensitize the target material with oxidizing elements. Of course, in other embodiments, the target material can also be pressed into tablets first and then annealed in an oxidizing atmosphere. It is expected that the doping and sensitization effect of the tablets will be worse than that of the powdered target material directly annealed in an oxidizing atmosphere.

[0032] In some embodiments, the oxidizing atmosphere includes, but is not limited to, any one of air, oxygen, ozone, and iodine vapor.

[0033] In some embodiments, the annealing temperature is 200° C. to 800° C., for example, 200° C., 250° C., 300° C., 350° C., 400° C., 450° C., 500° C., 550° C., 600° C., 650° C., 700° C., 750° C., or 800° C., and the annealing time is 8 to 15 hours. By controlling the above temperature and time, it is possible to achieve presensitization of the target material and control the doping amount and doping effect of the oxygen element.

[0034] In some embodiments, the physical vapor deposition method includes, but is not limited to, at least one of vacuum thermal evaporation and plasma sputtering. That is, the PbSe thin film can be formed by vacuum thermal evaporation or plasma sputtering alone, or a combination of vacuum thermal evaporation and plasma sputtering can be used to form a PbSe film of a predetermined thickness, thereby obtaining a PbSe film of a predetermined thickness.

[0035] It should be noted that because the presensitization process changes the target material, the inventors have discovered through research that specific deposition conditions are more conducive to the production of high-quality PbSe films. Therefore, in some embodiments, the sputtering power is controlled to 40W to 100W, for example, 40W, 45W, 48W, 50W, 55W, 60W, 65W, 70W, 75W, 80W, 85W, 90W, 95W, or 100W, and the distance between the substrate and the surface of the presensitized target is 5cm to 20cm.

[0036] In some implementations, the thickness of the PbSe infrared detection film is controlled to be 500 nm to 5000 nm according to product requirements.

[0037] Since the embodiments of the present invention do not require a high-temperature sensitization process, there are no significant restrictions on the substrate. Therefore, the substrate material includes, but is not limited to, any one of glass, quartz, sapphire, Si, SiO2, polyester, and polyisocyanate. For example, the substrate can be made of conventional high-temperature-resistant inorganic materials such as glass, quartz, sapphire, Si, and SiO2, or flexible organic materials that are not high-temperature-resistant, such as transparent polyester film (PPA), polyisocyanate (PI), and ordinary electrical polyester film (POLYSTER).

[0038] Furthermore, in some embodiments, prior to physical vapor deposition (PVD), the substrate is typically cleaned and pre-treated. The substrate is sequentially cleaned with an inorganic acid, an organic acid, and an organic solvent, dried, and then treated with ultraviolet ozone and oxygen plasma. No active heating or cooling measures are required during the PVD process. Furthermore, since the target material is pre-sensitized during PVD, there is no need to actively introduce an oxygen atmosphere during thin film deposition.

[0039] Some embodiments of the present invention further provide a PbSe infrared detection film, which is prepared by the preparation method of the PbSe infrared detection film provided by any of the above embodiments.

[0040] Some embodiments of the present invention also provide an infrared detector, which includes the PbSe infrared detection film of the above embodiment, that is, the PbSe film prepared based on the above-mentioned pre-sensitized target material. When preparing a metal thin film electrode, it is used as a single point or array infrared detector and applied to the field of photoelectric sensing.

[0041] In some embodiments, the infrared detector is a flexible wearable infrared detector. The preparation method in the above embodiment simplifies the preparation process of PbSe infrared detectors, greatly reduces the cost, and opens up the possibility of applying PbSe to large-area, high-precision, flexible wearable infrared detectors.

[0042] The features and performance of the present invention are further described in detail below with reference to the embodiments.

[0043] Example 1

[0044] This embodiment provides a method for preparing a PbSe infrared detection thin film, which includes the following steps:

[0045] Step 1: 1.73 g of PbO powder and 20.00 g of PbSe powder were placed in an agate mortar and ground for 60 min to ensure that the two powders were fully mixed. The obtained 10 at% oxygen-doped PbSe powder was pressed at a pressure of 20 MPa for 30 min using a powder tableting mold with a diameter of 55 mm to obtain a physical vapor deposition target.

[0046] Step 2: The substrate is made of electronic glass. Soak it in dilute nitric acid for 2 minutes, remove it and rinse it with deionized water. Place it in an acetic acid solution and ultrasonically clean it for 10 minutes. After removing it, rinse it with anhydrous ethanol and soak it in acetone solution for 10 minutes. After removing it, blow it dry with high-purity nitrogen. Place the cleaned substrate in a UV ozone cleaner for 1 minute. After removing it, place it in a plasma cleaner and select medium or high power for cleaning for 10 minutes. After cleaning, place the substrate in a dust-free transport box.

[0047] Step 3: Deposit the presensitized PbSe thin film using electron beam evaporation. Place the substrate on the evaporation fixture, with the substrate 20 cm away from the target. Pump the vacuum chamber to 1.8×10 -3 Pa, turn on the electron gun, set the voltage to 6kV, the current to 8mA, the evaporation time to 40s, and the film thickness is read by a film thickness monitor or measured using a step profiler. The final film thickness is 700nm.

[0048] Example 2

[0049] This embodiment provides a method for preparing a PbSe infrared detection thin film, which includes the following steps:

[0050] Step 1: Place 20g of PbSe powder in a clean, 50mm-diameter corundum crucible and heat to 350°C in an air atmosphere using a muffle furnace. Hold for 8 hours and then cool naturally. Remove the resulting powder and grind it for 60 minutes to evenly mix the components. Use a 55mm-diameter powder pressing mold to press the resulting powder at 20MPa for 3 minutes to obtain a physical vapor deposition target.

[0051] Step 2: The substrate is made of electronic glass. Soak it in dilute nitric acid for 2 minutes, remove it and rinse it with deionized water. Place it in an acetic acid solution and ultrasonically clean it for 10 minutes. After removing it, rinse it with anhydrous ethanol and soak it in acetone solution for 10 minutes. After removing it, blow it dry with high-purity nitrogen. Place the cleaned substrate in a UV ozone cleaner for 1 minute. After removing it, place it in a plasma cleaner and select medium or high power for cleaning for 10 minutes. After cleaning, place the substrate in a dust-free transport box.

[0052] Step 3: Deposit the presensitized PbSe thin film using electron beam evaporation. Place the substrate on the evaporation fixture, with the substrate 20 cm away from the target. Pump the vacuum chamber to 1.8×10 -3 Pa, turn on the electron gun, set the voltage to 6kV, the current to 8mA, the evaporation time to 40s, and the film thickness is read by a film thickness monitor or measured using a step profiler. The final film thickness is 700nm.

[0053] Example 3

[0054] This embodiment provides a method for preparing a PbSe infrared detection thin film, which includes the following steps:

[0055] Step 1: Place 1.85g of PbO2 powder and 20.00g of PbSe powder in an agate mortar and grind for 60 minutes to ensure that the two powders are fully mixed. Use a powder tableting mold with a diameter of 55mm to press the obtained 10at% oxygen-doped PbSe powder at a pressure of 20MPa for 30 minutes to obtain a physical vapor deposition target.

[0056] Step 2: The substrate is made of electronic glass. Soak it in dilute nitric acid for 2 minutes, remove it and rinse it with deionized water. Place it in an acetic acid solution and ultrasonically clean it for 10 minutes. After removing it, rinse it with anhydrous ethanol and soak it in acetone solution for 10 minutes. After removing it, blow it dry with high-purity nitrogen. Place the cleaned substrate in a UV ozone cleaner for 1 minute. After removing it, place it in a plasma cleaner and select medium or high power for cleaning for 10 minutes. After cleaning, place the substrate in a dust-free transport box.

[0057] Step 3: Deposit the presensitized PbSe thin film using electron beam evaporation. Place the substrate on the evaporation fixture, with the substrate 15 cm away from the target. Pump the vacuum chamber to 1.8×10 -3 Pa, turn on the electron gun, set the voltage to 8 kV, the current to 7 mA, and the evaporation time to 35 s.

[0058] Example 4

[0059] This embodiment provides a method for preparing a PbSe infrared detection thin film, which includes the following steps:

[0060] Step 1: Place 2.59g of PbI2 powder and 20.00g of PbSe powder in an agate mortar and grind for 60 minutes to ensure that the two powders are fully mixed. Use a powder pressing mold with a diameter of 55mm to press the obtained 10at% oxygen-doped PbSe powder at a pressure of 20MPa for 30 minutes to obtain a physical vapor deposition target.

[0061] Step 2: The substrate is made of electronic glass. Soak it in dilute nitric acid for 2 minutes, remove it and rinse it with deionized water. Place it in an acetic acid solution and ultrasonically clean it for 10 minutes. After removing it, rinse it with anhydrous ethanol and soak it in acetone solution for 10 minutes. After removing it, blow it dry with high-purity nitrogen. Place the cleaned substrate in a UV ozone cleaner for 1 minute. After removing it, place it in a plasma cleaner and select medium or high power for cleaning for 10 minutes. After cleaning, place the substrate in a dust-free transport box.

[0062] Step 3: Deposit the presensitized PbSe thin film using electron beam evaporation. Place the substrate on the evaporation fixture, with the substrate 10 cm away from the target. Pump the vacuum chamber to 1.8×10 -3 Pa, turn on the electron gun, set the voltage to 9 kV, the current to 7 mA, and the evaporation time to 30 s.

[0063] Example 5

[0064] This embodiment provides a method for preparing a PbSe infrared detection thin film, which includes the following steps:

[0065] Step 1: Place 0.82g PbO powder and 20.00g PbSe powder, 1.73g PbO powder and 20.00g PbSe powder, 2.75g PbO powder and 20.00g PbSe powder, and 3.90g PbO powder and 20.00g PbSe powder in an agate mortar and grind for 60 minutes to ensure that the two powders are fully mixed. Use a powder tableting mold with a diameter of 55mm to press the obtained 5at%, 10at%, 15at%, and 20at% oxygen-doped PbSe powders at a pressure of 20MPa for 30 minutes to obtain four physical vapor deposition targets.

[0066] Step 2: The substrate is made of electronic glass. Soak it in dilute nitric acid for 2 minutes, remove it and rinse it with deionized water. Place it in an acetic acid solution and ultrasonically clean it for 10 minutes. After removing it, rinse it with anhydrous ethanol and soak it in acetone solution for 10 minutes. After removing it, blow it dry with high-purity nitrogen. Place the cleaned substrate in a UV ozone cleaner for 1 minute. After removing it, place it in a plasma cleaner and select medium or high power for cleaning for 10 minutes. After cleaning, place the substrate in a dust-free transport box.

[0067] Step 3: Electron beam evaporation was used to deposit 5at%, 10at%, 15at%, and 20at% oxygen-doped presensitized PbSe films, respectively. The substrate was mounted on the evaporation fixture, with the substrate 20 cm away from the target. The vacuum chamber was evacuated to 1.8×10 - 3 Pa, turn on the electron gun, set the voltage to 6kV, the current to 8mA, the evaporation time to 40s, and the film thickness is read by a film thickness monitor or measured using a step profiler. The final film thickness is 700nm.

[0068] Example 6

[0069] This embodiment provides a method for preparing a PbSe infrared detection thin film, which includes the following steps:

[0070] Step 1: Place 20g of PbSe powder in a clean, 50mm-diameter corundum crucible and heat to 350°C in an air atmosphere using a muffle furnace. Hold for 8 hours and then cool naturally. Remove the resulting powder and grind it for 60 minutes to evenly mix the components. Use a 55mm-diameter powder pressing mold to press the resulting powder at 20MPa for 3 minutes to obtain a physical vapor deposition target.

[0071] Step 2: The substrate is made of electronic glass. Soak it in dilute nitric acid for 2 minutes, remove it and rinse it with deionized water. Place it in an acetic acid solution and ultrasonically clean it for 10 minutes. After removing it, rinse it with anhydrous ethanol and soak it in acetone solution for 10 minutes. After removing it, blow it dry with high-purity nitrogen. Place the cleaned substrate in a UV ozone cleaner for 1 minute. After removing it, place it in a plasma cleaner and select medium or high power for cleaning for 10 minutes. After cleaning, place the substrate in a dust-free transport box.

[0072] Step 3: Deposit the presensitized PbSe thin film using electron beam evaporation. Place the substrate on the evaporation fixture, with the substrate 20 cm away from the target. Pump the vacuum chamber to 1.8×10 -3 Pa, turn on the electron gun, set the voltage to 6kV, the current to 8mA; the voltage to 6kV, the current to 12mA, and the evaporation time to 40s. Two sample films were obtained.

[0073] Comparative Example 1

[0074] This comparative example provides a method for preparing a PbSe infrared detection thin film, which comprises the following steps:

[0075] Step 1: 20 g of pure PbSe powder was pressed into a powder tableting mold with a diameter of 55 mm at a pressure of 20 MPa for 30 min to obtain a physical vapor deposition target.

[0076] Step 2: Same as step 2 of Example 1.

[0077] Step 3: Same as step 3 of Example 1.

[0078] Comparative Example 2

[0079] This comparative example provides a method for preparing a PbSe infrared detection thin film, which comprises the following steps:

[0080] Step 1: Same as step 1 of comparative example 1.

[0081] Step 2: Same as step 2 in Example 1.

[0082] Step 3: Same as step 3 in Example 1.

[0083] Step 4: The obtained PbSe film was heated to 350° C. in an air atmosphere using a muffle furnace, kept at this temperature for 8 h, and then naturally cooled.

[0084] Test example

[0085] The PbSe films prepared in Example 1, Example 2 and Comparative Example 1 and Comparative Example 2 were characterized by XRD. The characterization results are shown in FIG. Figure 1 shown.

[0086] Depend on Figure 1 As can be seen, in Example 1, PbSe cubic phase crystal diffraction peaks and PbO diffraction peaks are clearly observed, indicating that the oxygen element is successfully incorporated into the PbSe film and the cubic phase lattice structure of PbSe is not destroyed. In Example 2, the same PbSeO3 and PbO byproduct diffraction peaks as in Comparative Example 2 appear, indicating that the presensitized film prepared by the method of the present invention is consistent in composition with the film prepared by the conventional method.

[0087] Au coplanar electrodes were prepared on the surfaces of the PbSe films prepared in Example 1, Example 2, and Comparative Example 1 and Comparative Example 2. The electrode spacing was 2 mm, and the infrared absorption effective area was 2×2 mm square. A copper wire with a diameter of 0.05 mm and a length of 30 mm was bonded to the Au electrode area using silver paste as a lead to obtain an infrared detection device based on the sensitized PbSe film. The result schematic diagram of the infrared detection device is shown in FIG. Figure 2 shown.

[0088] The current changes of the above four infrared detection devices in response to square wave pulse infrared radiation are compared. Among them, the infrared radiation source is a monochromatic light source with a wavelength of 4000nm, and the power density is 20, 30, 40, and 50mW / cm 2 The radiation source is incident vertically at a distance of 10 cm above the detector, and the square wave pulse is obtained through an electronic shutter with a pulse period of 20 seconds. Figure 3 As shown, from Figure 3 As can be seen, the incorporation of the wide-bandgap oxide reduces the intrinsic noise of Examples 1, 2, and Comparative Example 2. Simultaneously, due to the electron orbital resonance between O atoms and Pb atoms, new impurity energy levels are formed in the PbSe bandgap, reducing the PbSe bandgap while increasing the probability of stimulated radiative transitions of valence electrons, resulting in a significant increase in photocurrent. Furthermore, the photocurrents of Examples 1, 2, and Comparative Example 2 under infrared irradiation are comparable, demonstrating that the presensitization preparation methods of the present invention are comparable to conventional methods in improving the infrared detection performance of PbSe thin films.

[0089] The 5% atO, 10% atO, 15% atO, and 20% atO pbSe films prepared in Example 5 were characterized by XRD. The characterization results are shown in Figure 2. Figure 4As shown in the results, it can be found that with the increase of O doping ratio, the PbSe film gradually changes from tetragonal phase to amorphous state, that is, with the increase of oxygen content in the target material, the periodic structure of the lattice in the PbSe film is gradually destroyed, and the PbSe lattice changes from an ordered cubic arrangement to a disordered amorphous structure. Correspondingly, as Figure 5 As shown in the figure, the photocurrent of the film under infrared irradiation is first increased due to sensitization, but then the excessive incorporation of O atoms disrupts the lattice structure, hindering the transport of photogenerated carriers and causing a decrease in the film's photocurrent. Therefore, selecting an appropriate pre-sensitization doping ratio is crucial for preparing high-performance PbSe films.

[0090] In addition, deposition parameters also have an important influence on the final quality of PbSe films, such as Figure 6 As shown, the film produced in Example 6 using 6kV, 8mA evaporation conditions has a smooth surface, ideal for polycrystalline films. When the deposition current is increased to 12mA, the target atoms still possess extremely high kinetic energy when vaporized and transported to the substrate surface. During film nucleation and growth, this excess kinetic energy is converted into internal stress in the film, ultimately leading to cracking and warping.

[0091] Therefore, in summary, the preparation method of the PbSe infrared detection film of the present invention solves the problem that the existing PbSe film must undergo a high-temperature sensitization step after preparation, that is, it avoids the problems of element segregation of the PbSe film at high temperature, high temperature restriction of substrate type selection, and difficulty in compatibility with modern electronic manufacturing technology. By pre-sensitizing the target material for film preparation, selecting the appropriate doping atomic ratio and film deposition conditions, a sensitized PbSe film with uniform element distribution is directly prepared on various substrates. On the basis of obtaining such a film, a highly sensitive infrared detector is prepared using existing mature technical equipment. The detection rate (D*) reaches 10 under short-wave infrared and medium-wave infrared irradiation. 10 Jones, and can work at room temperature. This preparation method simplifies the preparation process of PbSe infrared detectors, greatly reduces the cost, and opens up the possibility of applying PbSe to large-area, high-precision, flexible, wearable infrared detectors.

[0092] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A method for preparing a PbSe infrared detection thin film, characterized in that: It includes: PbSe thin films were deposited on substrates using a pre-sensitized target by physical vapor deposition. The target material is PbSe.

2. The method for preparing a PbSe infrared detection thin film according to claim 1, wherein: The presensitized target is obtained by any of the following methods: (1) Adding one or more compound powders containing oxidizing elements into the target material; (2) Annealing the target in an oxidizing atmosphere.

3. The method for preparing the PbSe infrared detection thin film according to claim 2, wherein: The compound powder is incorporated by mechanical stirring, air flow mixing or liquid mixing.

4. The method for preparing a PbSe infrared detection thin film according to claim 3, wherein: The added compound powder includes one or a combination of two or more of PbO, PbO2, SeO2, PbS and PbI2.

5. The method for preparing a PbSe infrared detection thin film according to claim 4, wherein: The atomic ratio of doping is 0.1% to 30%.

6. The method for preparing a PbSe infrared detection thin film according to claim 5, wherein: The atomic ratio of doping is 9.5% to 10.5%.

7. The method for preparing a PbSe infrared detection thin film according to claim 6, wherein: The atomic ratio of incorporation is 10%.

8. The method for preparing a PbSe infrared detection thin film according to claim 4, wherein: The uniform mixture of the target material and the compound powder is pressed into a tablet to obtain the presensitized target.

9. The method for preparing a PbSe infrared detection thin film according to claim 8, wherein: The target material in powder form is first annealed in an oxidizing atmosphere, and then the target material is pressed into tablets.

10. The method for preparing a PbSe infrared detection thin film according to claim 9, wherein: The oxidizing atmosphere includes any one of air, oxygen, ozone and iodine vapor.

11. The method for preparing a PbSe infrared detection thin film according to claim 9, wherein: The annealing temperature is 200° C. to 800° C., and the annealing time is 8 to 15 hours.

12. The method for preparing a PbSe infrared detection thin film according to claim 1, wherein: The physical vapor deposition method includes at least one of vacuum thermal evaporation and plasma sputtering.

13. The method for preparing a PbSe infrared detection thin film according to claim 12, wherein: The sputtering power is 40W to 100W, and the distance between the substrate and the surface of the pre-sensitized target material is 5cm to 20cm.

14. The method for preparing a PbSe infrared detection thin film according to claim 13, wherein: The thickness of the PbSe infrared detection film is controlled to be 500nm to 5000nm.

15. The method for preparing a PbSe infrared detection thin film according to claim 1, wherein: The material of the substrate includes any one of glass, quartz, sapphire, Si, SiO2, polyester and polyisocyanate.

16. A PbSe infrared detection film, characterized in that: The compound is prepared by the preparation method according to any one of claims 1 to 15.

17. An infrared detector, characterized in that: It includes the PbSe infrared detection film as claimed in claim 16.

18. The infrared detector according to claim 17, characterized in that: The infrared detector is a flexible wearable infrared detector.

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