Method for realizing compatibility of medium-long wave infrared transparency and conductivity in thin film material

Abstract

The invention belongs to the technical field of functional materials, and particularly relates to a method for realizing compatibility of medium-long wave infrared transparency and conductivity in a thin film material, and the compatibility of medium-long wave infrared transparency and conductivity is realized by regulating the carrier relaxation time tau to be less than 0.1 fs and the carrier concentration n to be greater than 1.0 * 10 < 20 > cm <-3 >. Specifically, the medium-long wave infrared transparent conductive film with the relaxation time tau smaller than 0.1 fs and the carrier concentration n larger than 1.0 * 10 < 20 > cm <-3 > is obtained by preparing a BiSexTe < 1-x > solid solution material. The preparation process of the BiSexTe1-x solid solution material comprises the following steps: mounting pure BiTe and Bi2Se3 target materials on a magnetron radio frequency sputtering target, and taking a high-purity intrinsic silicon wafer or a zinc sulfide sheet as a substrate; vacuumizing, and introducing high-purity Ar gas; and controlling the sputtering power of the pure BiTe target material and the Bi2Se3 target material, and co-sputtering and depositing the BiSexTe1-x film on the substrate. Compared with a traditional method for regulating and controlling carrier concentration or effective quality, the method has the advantage that the compatibility of far infrared transparency and conductivity can be well realized in a thin film material.

Description

Technical Field

[0001] The present invention belongs to the technical field of functional materials, and in particular relates to a method for achieving compatibility of mid- and long-wave infrared transparency and electrical conductivity in a thin film material. Background Art

[0002] As a key material for new infrared optoelectronic devices, infrared transparent conductive films have important application prospects in radar stealth, anti-electromagnetic interference, photoelectric detection and other fields. The core challenge is to simultaneously achieve high transmittance and high conductivity in the 3-12μm band, which involves breaking through the carrier transport characteristics. and plasma wavelength and the inherent constraint relationship between carrier intraband transition absorption (κ∝τ).

[0003] The traditional design of infrared transparent conductive film materials is mainly based on the p Regulation, such as increasing the effective mass m* through electron-electron interaction, slowing down the carrier response speed, and reducing the plasma oscillation frequency, thereby increasing λ p , such as metal salts such as SrVO3 and CaVO3. However, the adjustable range of m* is limited, which causes SrVO3 and other thin films to show the best performance only in the near infrared. In recent years, there have been reports on increasing the optical dielectric constant ε opt , weakening the Coulomb binding of the ion to the free electrons, thereby significantly increasing λ p , making it fall outside 14μm, significantly improving infrared transparency. 2.4 The optical dielectric constant ε is effectively increased through the octahedral coordination of Se and the formation of a few-electron multi-center bond. opt (>15), effectively increasing λ p , the transmittance in the 8-12μm band is >90%, and the conductivity σ is limited to less than 1000S / cm. From the existing methods, only through n, m* and ε opt To control λ p , the obtained materials are difficult to achieve compatibility of infrared transparency and conductivity at the same time.

[0004] The main reasons why it is difficult to achieve breakthroughs in performance at present are that the above strategies only focus on the effect of plasma reflection on the infrared transparent conductive properties of thin films, lack research on the absorption loss of carrier intra-band transitions, and there is no relevant experience to draw on for balancing carrier absorption and transport by regulating carrier concentration and relaxation time.

[0005] In view of this, there is an urgent need to provide a method to achieve compatible mid- and long-wave infrared transparency and conductivity in thin film materials. Summary of the Invention

[0006] The purpose of the present invention is to overcome the above-mentioned problems existing in traditional technologies and provide a method for achieving compatibility of medium and long-wave infrared transparency and conductivity in thin film materials, so as to obtain thin film materials with both high, medium and long-wave infrared transmittance and high conductivity.

[0007] In order to achieve the above technical objectives and the above technical effects, the present invention is implemented through the following technical solutions:

[0008] The present invention provides a method for achieving compatibility between mid- and long-wave infrared transparency and conductivity in thin film materials by regulating the carrier relaxation time τ to be less than 0.1 fs and the carrier concentration n to be greater than 1.0×10 20 cm -3 , achieving the compatibility of long-wave infrared transparency and conductive properties in thin film materials.

[0009] Furthermore, the method of achieving compatibility of mid- and long-wave infrared transparency and conductivity in thin film materials as described above is carried out by preparing BiSe x Te 1-x Solid solution materials are used to obtain carrier relaxation time τ less than 0.1fs and carrier concentration n greater than 1.0×10 20 cm -3 Mid- and long-wave infrared transparent conductive films.

[0010] Furthermore, as described above, the method of achieving compatibility of mid- and long-wave infrared transparency and conductivity in thin film materials is based on a natural superlattice (Bi2Te3)2+Bi double layer, a hexagonal system The topological semimetal BiTe with a band gap of 70 meV, weak topological surface states, high-frequency dielectric constant <15, and intrinsic conductivity >2000 S / cm is used as the solvent material. Se elements are introduced as solute atoms. By regulating the thickness of BiSe x Te 1-x The Se content in the solid solution material is such that x = 0.1 to 0.5, so as to obtain τ less than 0.1 fs and carrier concentration n greater than 1.0×10 20 cm -3 Mid- and long-wave infrared transparent conductive films.

[0011] Furthermore, as described above, the method for achieving compatibility of mid- and long-wave infrared transparency and conductivity in thin film materials, the BiSe x Te 1-x The material preparation process includes the following steps:

[0012] 1) In a magnetron sputtering coating system, pure BiTe and Bi2Se3 targets are installed in a magnetron RF sputtering target, and high-purity intrinsic silicon wafers or zinc sulfide wafers are used as substrates;

[0013] 2) Evacuate the sputtering chamber of the magnetron sputtering coating system until the vacuum degree in the chamber reaches the required vacuum degree, and then introduce high-purity Ar gas into the sputtering chamber until the pressure in the sputtering chamber reaches the ignition pressure required for sputtering;

[0014] 3) Control the sputtering power of pure BiTe and Bi2Se3 targets, and the thin film material deposited on the substrate is BiSe x Te 1-x Material.

[0015] Furthermore, in step 1), the substrate is ultrasonically cleaned in acetone, ethanol and deionized water in sequence.

[0016] Furthermore, in step 2), the required vacuum degree is 4×10 -4 ~6×10 -4 Pa, the required ignition pressure is 0.5~1.0Pa.

[0017] Furthermore, in step 3), a radio frequency power supply is used for the pure BiTe target, and the sputtering power is 50 to 70 W; a radio frequency power supply is used for the pure Bi2Se3 target, and the sputtering power is 60 to 90 W.

[0018] Furthermore, in step 3), the sputtering conditions are: target-substrate distance 22 cm, substrate temperature RT, working pressure 0.45-0.55 Pa, Ar gas flow rate 59-61 sccm, and sputtering time 24-55 s.

[0019] The present invention also provides an infrared transparent conductive film, which is a medium- and long-wave infrared transparent conductive film prepared according to the above method.

[0020] The beneficial effects of the present invention are:

[0021] 1. The present invention provides a method for achieving compatible mid- and long-wave infrared transparency and conductivity in thin film materials. Compared with the traditional method of regulating carrier concentration or effective mass, this method uses hexagonal crystals to phase, the stoichiometric ratio is 1:1, bismuth telluride with weak topological surface state is used as solvent material, Se element is introduced as solute atom, and the thickness of BiSe is 10nm. x Te 1-x The Se content x (x = 0.1 to 0.5) in the solid solution material is such that τ is less than 0.1 fs and the carrier concentration n is greater than 1.0×10 20 cm -3 The medium and long wave infrared transparent conductive film realizes the compatibility of medium and long wave infrared transparency and conductive properties of the film material.

[0022] 2. Preparation of BiSe with a relaxation time τ of 0.0784 fs and a stoichiometric ratio x = 0.5 by the present invention0.5 Te 0.5 The infrared transparent conductive film has a conductivity of up to 7246S / cm and an average transmittance of 84% in the range of 3 to 12μm, achieving compatibility between medium and long-wave infrared transparency and conductive properties. This good compatibility cannot be achieved by any other reported conductive film or transparent film.

[0023] Of course, any product implementing the present invention does not necessarily need to achieve all of the above advantages at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0025] Figure 1 BiSe with different Se contents prepared by the present invention x Te 1-x Schematic diagram of the mid- and long-wave infrared transparent conductive properties of solid solution films;

[0026] Figure 2 BiSe with different Se contents prepared by the present invention x Te 1-x XRD pattern of solid solution thin film;

[0027] Figure 3 BiSe prepared by the present invention x Te 1-x EDS spectrum of solid solution film. DETAILED DESCRIPTION

[0028] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0029] The conception process of the present invention is described as follows:

[0030] The inventors found through first-principles calculations and optical dielectric function simulations that the carrier concentration n and relaxation time τ can be used to regulate the carrier transport properties of thin films. and plasma wavelength The inherent constraint between the absorption of carriers and intraband transitions (κ∝τ) is revealed. Through first-principles calculations and optical dielectric function simulations, the inventors discovered that infrared transmittance is closely related to intraband carrier transition absorption, which in turn is proportional to the carrier relaxation time τ. Material conductivity is closely related to mobility μ, which in turn is closely related to carrier relaxation time τ. Therefore, the inventors propose that a small carrier relaxation time τ is key to achieving synergistic long-wave infrared transparency and conductivity in dielectric materials.

[0031] The inventors used the first principles method of density functional theory (DFT) to study the 0.5 Te 0.5 The band structure and electron delocalization degree of BiTe were systematically analyzed. First, the initial lattice model of BiTe was built in the Materials Studio platform, and strict geometry optimization was performed using VASP. Then, Se atoms were used to replace some Te atoms in BiTe to form BiSe. 0.5 Te 0.5 structure, and the Drude-Lorentz model was used to analyze BiTe and BiSe 0.5 Te 0.5 Transmission spectra of the two films were fitted to elucidate the relationship between carrier transport performance, plasma wavelength, and carrier intraband transition absorption. Through extensive first-principles calculations, the inventors selected solvents such as BiTe and BiSe and solute atoms such as Se and Te to form solid solution materials. They also simulated the solid solution distribution and component ratios of a large number of solute atoms in the parent material, ultimately optimizing the optimal solid solution structure, such as BiTe solid solution with Se atoms. To achieve high conductivity, the inventors manipulated the stoichiometric ratio x (x = 0.1 to 0.5) of the non-metallic element Se to achieve the desired solid solution. When Se atoms partially replace Te atoms, shallow donor level defects are formed at the bottom of the conduction band, gradually widening the conduction band, indicating enhanced electron delocalization in this region. This broadening effect promotes the transition of valence band electrons to the conduction band, thereby increasing the density of available electronic states near the Fermi level and improving conductivity.

[0032] The relevant specific embodiments of the present invention are as follows:

[0033] Example 1

[0034] This embodiment provides a method for achieving compatibility between mid- and long-wave infrared transparency and electrical conductivity in thin film materials. phase, the stoichiometric ratio is 1:1, bismuth telluride with weak topological surface state is used as solvent material, Se element is introduced as solute atom, and the thickness of BiSe is 10nm. x Te 1-xThe Se content in the solid solution material is x (x = 0.1) to obtain a τ less than 0.1 fs and a carrier concentration n greater than 1.0×10 20 cm -3 The mid- and long-wave infrared transparent conductive film achieves the compatibility of mid-infrared transparency and conductive properties of the film material.

[0035] In this example, BiSe 0.1 Te 0.9 Solid solution materials are used to obtain dielectric films with relaxation time τ less than 0.1fs, BiSe 0.1 Te 0.9 The preparation process of solid solution material includes the following steps:

[0036] 1) In a magnetron sputtering coating system, pure BiTe and Bi2Se3 targets are installed in a magnetron radio frequency sputtering target head, and high-purity intrinsic silicon wafers or zinc sulfide wafers are used as substrates.

[0037] 2) The sputtering chamber of the magnetron sputtering coating system is evacuated until the vacuum degree in the chamber reaches the required vacuum degree, and then high-purity Ar gas is introduced into the sputtering chamber until the pressure in the sputtering chamber reaches the ignition pressure required for sputtering.

[0038] 3) Control the sputtering power of pure BiTe and Bi2Se3 targets. The pure BiTe target uses a radio frequency power supply with a sputtering power of 60W, and the pure Bi2Se3 target uses a radio frequency power supply with a sputtering power of 30W. The thin film material deposited on the substrate is BiSe 0.1 Te 0.9 Solid solution material. Sputtering conditions are: target-substrate distance 22 cm, substrate temperature RT, working pressure 0.5 Pa, Ar gas flow rate 60 sccm, and sputtering time 55 s.

[0039] Example 2

[0040] This embodiment provides a method for achieving compatibility between mid- and long-wave infrared transparency and electrical conductivity in thin film materials. phase, the stoichiometric ratio is 1:1, bismuth telluride with weak topological surface state is used as solvent material, Se element is introduced as solute atom, and the thickness of BiSe is 10nm. x Te 1-x The Se content in the solid solution material is x (x = 0.5) to obtain τ less than 0.1fs and carrier concentration n greater than 1.0×10 20 cm -3 The mid- and long-wave infrared transparent conductive film achieves the compatibility of mid-infrared transparency and conductive properties of the film material.

[0041] In this example, BiSe 0.5 Te 0.5Solid solution materials are used to obtain dielectric films with relaxation time τ less than 0.1fs, BiSe 0.5 Te 0.5 The preparation process of solid solution material includes the following steps:

[0042] 1) In a magnetron sputtering coating system, pure BiTe and Bi2Se3 targets are installed in a magnetron radio frequency sputtering target head, and high-purity intrinsic silicon wafers or zinc sulfide wafers are used as substrates.

[0043] 2) The sputtering chamber of the magnetron sputtering coating system is evacuated until the vacuum degree in the chamber reaches the required vacuum degree, and then high-purity Ar gas is introduced into the sputtering chamber until the pressure in the sputtering chamber reaches the ignition pressure required for sputtering.

[0044] 3) Control the sputtering power of pure BiTe and Bi2Se3 targets. The pure BiTe target uses a radio frequency power supply with a sputtering power of 60W, and the pure Bi2Se3 target uses a radio frequency power supply with a sputtering power of 60W. The thin film material deposited on the substrate is BiSe 0.5 Te 0.5 Solid solution material. Sputtering conditions are: target-substrate distance 22 cm, substrate temperature RT, working pressure 0.5 Pa, Ar gas flow rate 60 sccm, and sputtering time 40 s.

[0045] The inventors selected BiSe in Example 2 0.5 Te 0.5 Verification experiments on the solid solution material revealed a relaxation time τ of 0.0784 fs, a high conductivity of 7246 S / cm, and an average transmittance of 84% in the 3-12 μm range, as measured by four-point probe and spectroscopy. This example demonstrates the compatibility of mid- and long-wave infrared transparency and conductivity in a thin film material, a balance unattainable by any previously reported conductive or transparent film. This material exhibits both excellent infrared transmittance and conductivity, potentially meeting the development needs of next-generation infrared optoelectronic devices.

[0046] The preferred embodiments of the present invention disclosed above are intended only to help illustrate the present invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the present invention to specific embodiments. Obviously, many modifications and variations are possible based on the contents of this specification. These embodiments are selected and described in detail in this specification to better explain the principles and practical applications of the present invention, thereby enabling those skilled in the art to better understand and utilize the present invention. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A method for achieving compatibility of mid- and long-wave infrared transparency and electrical conductivity in a thin film material, characterized in that: By adjusting the carrier relaxation time τ to less than 0.1 fs and the carrier concentration n to greater than 1.0×10 20 cm -3 , achieving the compatibility of long-wave infrared transparency and conductive properties in thin film materials.

2. The method for achieving compatibility of mid- and long-wave infrared transparency and conductivity in a thin film material according to claim 1, characterized in that: By preparing BiSe x Te 1-x Solid solution materials are used to obtain carrier relaxation time τ less than 0.1fs and carrier concentration n greater than 1.0×10 20 cm -3 Mid- and long-wave infrared transparent conductive films.

3. The method for achieving compatibility of mid- and long-wave infrared transparency and conductivity in a thin film material according to claim 2, characterized in that: Based on natural superlattice (Bi2Te3)2+Bi double layer, hexagonal system The topological semimetal BiTe with a band gap of 70 meV, weak topological surface states, high-frequency dielectric constant <15, and intrinsic conductivity >2000 S / cm is used as the solvent material. Se elements are introduced as solute atoms. By regulating the thickness of BiSe x Te 1-x The Se content in the solid solution material is such that x = 0.1 to 0.5, so as to obtain τ less than 0.1 fs and carrier concentration n greater than 1.0×10 20 cm -3 Mid- and long-wave infrared transparent conductive films.

4. The method for achieving compatibility of mid- and long-wave infrared transparency and conductivity in a thin film material according to claim 3, characterized in that: The BiSe x Te 1-x The material preparation process includes the following steps: 1) In a magnetron sputtering coating system, pure BiTe and Bi2Se3 targets are installed in a magnetron RF sputtering target, and high-purity intrinsic silicon wafers or zinc sulfide wafers are used as substrates; 2) Evacuate the sputtering chamber of the magnetron sputtering coating system until the vacuum degree in the chamber reaches the required vacuum degree, and then introduce high-purity Ar gas into the sputtering chamber until the pressure in the sputtering chamber reaches the ignition pressure required for sputtering; 3) Control the sputtering power of pure BiTe and Bi2Se3 targets, and the thin film material deposited on the substrate is BiSe x Te 1-x Material.

5. The method for achieving compatibility of mid- and long-wave infrared transparency and conductivity in a thin film material according to claim 4, characterized in that: In step 1), the substrate is ultrasonically cleaned in acetone, ethanol and deionized water in sequence.

6. The method for achieving compatibility of mid- and long-wave infrared transparency and conductivity in a thin film material according to claim 4, characterized in that: In step 2), the required vacuum degree is 4×10 -4 ~6×10 -4 Pa, the required ignition pressure is 0.5~1.0Pa.

7. The method for achieving compatibility of mid- and long-wave infrared transparency and conductivity in a thin film material according to claim 4, characterized in that: In step 3), a radio frequency power supply is used for the pure BiTe target, and the sputtering power is 50 to 70 W; a radio frequency power supply is used for the pure Bi2Se3 target, and the sputtering power is 60 to 90 W.

8. The method for achieving compatibility of mid- and long-wave infrared transparency and conductivity in a thin film material according to claim 4, characterized in that: In step 3), the sputtering conditions are: target-substrate distance 22 cm, substrate temperature RT, working pressure 0.45-0.55 Pa, Ar gas flow rate 59-61 sccm, and sputtering time 24-55 s.

9. An infrared transparent conductive film, characterized in that: The film is a medium- and long-wave infrared transparent conductive film prepared according to the method described in any one of claims 1 to 8.

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