Infrared phase change material couple with high and low dielectric imaginary parts and preparation method thereof

Abstract

The application belongs to the technical field of optical functional film materials, and particularly relates to an infrared phase change material pair with high and low dielectric imaginary parts and a preparation method thereof. The phase change material pair is formed by superimposing two phase change materials with high and low crystalline state dielectric imaginary parts. The crystalline state dielectric imaginary part is in the infrared wave band of 3-15 mu m, and the difference between the average dielectric imaginary parts of the two phase change materials in the wave band is greater than or equal to 100. The infrared phase change material pair can switch between transmission, absorption and reflection modes through temperature modulation in a wide mid-infrared wavelength range (3-15 mu m). This dynamic response function can be used as a non-volatile dynamic infrared modulation body and widely applied to next-generation intelligent optical elements such as intelligent optical switches and multifunctional filters, thereby filling the gap in the prior art.

Description

Technical Field

[0001] This invention belongs to the field of optical functional thin film materials technology, specifically relating to an infrared phase change material couple with high and low dielectric imaginary parts and its preparation method. Background Technology

[0002] Controlling the transmittance, absorptivity, and reflectivity of optical thin films is crucial in optical component applications, such as anti-reflective coatings, optical filters, and absorbers. Typically, the characteristics of optical components can be adjusted by designing thin film structures and materials. However, once these structures and materials are manufactured, they remain fixed, and the associated optical properties cannot be changed. With the development of modern civilian and military technologies, chalcogenide phase change materials are widely used as optical layers in optical components. Under external light and electrical excitation, they can undergo non-volatile phase transitions, resulting in significant optical contrast, which provides optical components with switchable new properties. In recent years, non-volatile dynamic infrared modulators based on chalcogenide phase change materials have become a research hotspot in many fields, including dynamic camouflage, reconfigurable optoelectronic devices, radiative cooling, thermophotovoltaics, and smart optical switches.

[0003] For example, researchers have used Ge3Sb2Te6 as the absorption layer to prepare a perfect mid-infrared (3-5 μm) absorber and achieved a redshift in the absorption spectrum, demonstrating multispectral thermal imaging capabilities. Furthermore, other researchers have developed an optical switch based on a combination of Ge2Sb2Te5 and VO2, which can switch the average reflectance in four levels from 0.6 to 1.0 in the visible light range (390-760 nm). However, because a single phase change material is used as the dynamic layer, these switchable properties can only achieve adjustment of a single characteristic: either shifting the resonance peak in the spectrum or achieving single-mode switching of the on / off state. Moreover, these results have only been studied within a relatively narrow spectral range.

[0004] Therefore, research on the control of multiple optical properties over a wide wavelength range is urgently needed. Summary of the Invention

[0005] The purpose of this invention is to overcome the aforementioned problems in conventional technologies and to provide an infrared phase change material couple with high and low dielectric imaginary parts and its preparation method.

[0006] To achieve the above-mentioned technical objectives and effects, the present invention is implemented through the following technical solution:

[0007] An infrared phase change material couple with high and low imaginary dielectric parts is provided. The phase change material couple is composed of two phase change materials with high and low imaginary dielectric parts in the crystalline state. Specifically, it is composed of phase change material A, which is located in the upper layer and has a high imaginary dielectric part, and phase change material B, which is located in the lower layer and has a low imaginary dielectric part. The imaginary dielectric part in the crystalline state is in the infrared band of 3-15μm, and the difference between the average imaginary dielectric parts of the two phase change materials in the crystalline state in this band is ≥100.

[0008] Furthermore, in the aforementioned infrared phase change material pair with high and low dielectric imaginary parts, the thickness of the phase change material A is greater than the skin depth of its crystalline state in the 3-15 μm band.

[0009] Furthermore, in the aforementioned infrared phase change material pair with high and low dielectric imaginary parts, the phase change material A has a low vacancy concentration, low average electronegativity, and high phase change activation energy.

[0010] Furthermore, in the aforementioned infrared phase change material pair with high and low dielectric imaginary parts, the phase change material A is one of AgBiTe2, AgSbTe2, and In3SbTe2.

[0011] Furthermore, in the aforementioned infrared phase change material pair with high and low dielectric imaginary parts, the thickness of the phase change material B is close to or equal to the skin depth of its crystalline state in the 3-15μm band.

[0012] Furthermore, in the aforementioned infrared phase change material pair with high and low dielectric imaginary parts, the phase change material B has a high vacancy concentration, high average electronegativity, and low phase change activation energy.

[0013] Furthermore, in the aforementioned infrared phase change material couple with high and low dielectric imaginary parts, the phase change material B is one of Ge3Sb4Te8, Ge3Sb2Te6, and GeTe4.

[0014] Furthermore, the preparation method of the aforementioned infrared phase change material couple with high and low dielectric imaginary parts specifically includes the following steps:

[0015] S1. Phase change material A is used as target A, and phase change material B is used as target B. In the magnetron sputtering coating system, target A and target B are installed at their respective target positions, and ZnS is used as the substrate.

[0016] S2. Evacuate the sputtering chamber of the magnetron sputtering coating system until the vacuum level in the chamber reaches the set value, and then introduce high-purity Ar gas into the sputtering chamber until the gas pressure in the sputtering chamber reaches the starting gas pressure required for sputtering.

[0017] S3. Using an RF power supply, adjust the power, target-substrate distance, working pressure and Ar gas flow rate of target A and target B, and sputter target A and target B on the substrate in sequence. Control the film thickness of target A and target B respectively during the sputtering process to obtain a double-layer thin film material.

[0018] S4. Annealing is performed in a tube furnace with an Ar atmosphere to obtain a crystalline thin film material.

[0019] The beneficial effects of this invention are:

[0020] 1. The infrared phase change material couple proposed in this invention can switch between transmission, absorption, and reflection modes through temperature modulation over a wide mid-infrared wavelength range (3-15μm). This dynamic response function can be used as a non-volatile dynamic infrared modulator and is widely applied in next-generation intelligent optical components such as smart optical switches and multifunctional filters, filling a gap in existing technologies.

[0021] 2. This invention is based on in-depth research and analysis of a series of phase change materials with significant differences in dielectric properties, except for In3SbTe2 and G. e3 Besides Sb4Te8, a large number of other phase change materials can also be used as components of phase change material pairs. Using phase change materials with different atomic structures and chemical compositions, dynamic modulators with operating wavelengths covering the visible-infrared spectral range can be realized, bringing a series of candidate materials to related fields.

[0022] 3. This invention proposes the concept of infrared phase change material couple, that is, using two materials simultaneously in the same system. It is not limited to the dynamic modulator shown, but can also be extended to other nanophotonics fields (such as polarization control). This fundamentally improves the modulation capability of nanophotonic devices and opens up new avenues.

[0023] Of course, any product implementing this invention does not necessarily need to achieve all of the above advantages at the same time. Attached Figure Description

[0024] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a conceptual diagram of the infrared phase change material couple of the present invention;

[0026] Figure 2 This is a screening spectrum of the component materials of the infrared phase change material couple of the present invention;

[0027] Figure 3This invention relates to the infrared dielectric imaginary part dispersion spectrum of the phase change material.

[0028] Figure 4 This invention relates to the configuration and simulated infrared spectrum of the In3SbTe2 / Ge3Sb4Te8 couple used as an infrared transmitter;

[0029] Figure 5 This invention describes the configuration and simulated infrared spectrum of the In3SbTe2 / Ge3Sb4Te8 couple used as an infrared absorber.

[0030] Figure 6 This invention relates to the configuration and simulated infrared spectrum of In3SbTe2 / Ge3Sb4Te8 as an infrared reflector. Detailed Implementation

[0031] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] This invention provides an infrared phase change material couple with high and low imaginary dielectric parts. The phase change material couple is composed of two phase change materials with high and low imaginary dielectric parts in the crystalline state, respectively. Specifically, it is composed of phase change material A, which is located in the upper layer and has a high imaginary dielectric part, and phase change material B, which is located in the lower layer and has a low imaginary dielectric part. The imaginary dielectric part in the crystalline state is in the infrared band of 3-15μm, and the difference between the average imaginary dielectric parts of the two phase change materials in the crystalline state in this band is ≥100.

[0033] Phase change material A has a thickness greater than its skin depth in the 3-15 μm wavelength range. Phase change material A exhibits low vacancy concentration, low average electronegativity, and high phase change activation energy. Phase change material B has a thickness close to or equal to its skin depth in the 3-15 μm wavelength range. Phase change material B exhibits high vacancy concentration, high average electronegativity, and low phase change activation energy.

[0034] according to Figure 1 Configuration requirements and Figure 2 Based on the material requirements, phase change materials A and B that meet the requirements can be selected for structural design and fabrication. Figure 3 It is known that candidate materials with low vacancy concentration and low average electronegativity include AgBiTe2, AgSbTe2, and In3SbTe2; candidate materials with high vacancy concentration and high average electronegativity include Ge3Sb4Te8, Ge3Sb2Te6, and GeTe4.

[0035] This invention also provides a method for preparing an infrared phase change material couple with high and low imaginary dielectric parts, specifically including the following steps:

[0036] S1. Phase change material A is used as target A, and phase change material B is used as target B. In the magnetron sputtering coating system, target A and target B are installed at their respective target positions, and ZnS is used as the substrate.

[0037] S2. Evacuate the sputtering chamber of the magnetron sputtering coating system until the vacuum level in the chamber reaches the set value, and then introduce high-purity Ar gas into the sputtering chamber until the gas pressure in the sputtering chamber reaches the starting gas pressure required for sputtering.

[0038] S3. Using an RF power supply, adjust the power, target-substrate distance, working pressure and Ar gas flow rate of target A and target B, and sputter target A and target B on the substrate in sequence. Control the film thickness of target A and target B respectively during the sputtering process to obtain a double-layer thin film material.

[0039] S4. Annealing is performed in a tube furnace with an Ar atmosphere to obtain a crystalline thin film material.

[0040] The relevant specific embodiments of the present invention are as follows:

[0041] Example 1

[0042] Taking the phase change material In3SbTe2 / Ge3Sb4Te8 as an example:

[0043] Depend on Figure 3 It is known that the difference in the imaginary part of the average dielectric constant in the crystalline state between In3SbTe2 and Ge3Sb4Te8 exceeds 300 in the 3-15 μm range. Furthermore, the phase transition temperatures of In3SbTe2 and Ge3Sb4Te8 are 250 °C and 190 °C, respectively, demonstrating a significant difference in their phase transition activation energies. Therefore, In3SbTe2 and Ge3Sb4Te8 satisfy all the necessary conditions for forming an infrared phase change material couple.

[0044] The preparation method of the phase change material In3SbTe2 / Ge3Sb4Te8 specifically includes the following steps:

[0045] S1. In the magnetron sputtering coating system, high-purity In3SbTe2 and Ge3Sb4Te8 targets are installed at their respective target positions, and ZnS is used as the substrate.

[0046] S2. Evacuate the sputtering chamber of the magnetron sputtering coating system until the vacuum level reaches 4×10⁻⁶. -4 -4.5×10 -4 Pa, and then high-purity Ar gas is introduced into the sputtering chamber until the gas pressure in the sputtering chamber reaches the starting gas pressure of 0.5 Pa required for sputtering;

[0047] S3. Using an RF power supply, the power of the Ge3Sb4Te8 target and the In3SbTe2 target was adjusted to 80W, the target-substrate distance was 60mm, the working pressure was 0.5Pa, and the Ar gas flow rate was 80sccm. The Ge3Sb4Te8 and In3SbTe2 targets were sputtered sequentially on the substrate to obtain a bilayer thin film material. The film thicknesses of Ge3Sb4Te8 and In3SbTe2 were controlled at 1000nm and 300nm, respectively.

[0048] S4. Annealing is performed in a tube furnace under an Ar atmosphere to obtain a crystalline thin film material. High-purity Ar gas is passed through for 30 minutes before annealing at a flow rate of 300 sccm. The annealing temperature is 150-280℃, the annealing time is 50-95 minutes, the holding time is 30 minutes, and then the material is allowed to cool naturally.

[0049] Taking In3SbTe2 and Ge3Sb4Te8 as two candidate materials, we studied the optical properties of the In3SbTe2 / Ge3Sb4Te8 couple as a non-volatile dynamic infrared modulator.

[0050] like Figures 4-6 As shown, through extensive numerical simulations, the structural configuration and transmission / reflection / absorption spectra of the In3SbTe2 / Ge3Sb4Te8 pair in the 3-15 μm band were obtained. The thicknesses of In3SbTe2 and Ge3Sb4Te8 were 300 nm and 1000 nm (without substrate), respectively, chosen based on their skin depths in this band (approximately 50 and 1200 nm).

[0051] As can be seen, with the successive phase transitions of the components in the In3SbTe2 / Ge3Sb4Te8 pair (amorphous / amorphous → amorphous / crystalline → crystalline / crystalline), its optical properties change from selective perfect transmission (infrared transmitter), through selective absorption (infrared absorber), to a non-dispersive high reflectance mode (infrared reflector). Simultaneously, due to the significant difference in phase transition temperatures between the two phase transition materials, the aforementioned "amorphous / amorphous → amorphous / crystalline → crystalline / crystalline" phase transition process can be achieved through a simple linear annealing process.

[0052] In summary, the In3SbTe2 / Ge3Sb4Te8 pair can perfectly realize the optical functions of non-volatile dynamic infrared modulators, opening up new directions for the field of infrared thin film optics.

[0053] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to specific implementations. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. An infrared phase change material couple with high and low imaginary dielectric parts, characterized in that: The phase change material is composed of two phase change materials with high and low crystalline state dielectric imaginary parts. Specifically, it is composed of phase change material A, which is located in the upper layer and has a high dielectric imaginary part, and phase change material B, which is located in the lower layer and has a low dielectric imaginary part. The crystalline state dielectric imaginary part is in the infrared band of 3-15μm, and the difference between the average crystalline state dielectric imaginary parts of the two phase change materials in this band is ≥100. The thickness of phase change material A is greater than its skin depth in the 3-15μm band of crystallization, and the thickness of phase change material B is close to or equal to its skin depth in the 3-15μm band of crystallization. Compared with phase change material B in terms of vacancy concentration, average electronegativity, and phase change activation energy, phase change material A has low vacancy concentration, low average electronegativity, and high phase change activation energy, while phase change material B has high vacancy concentration, high average electronegativity, and low phase change activation energy.

2. The infrared phase change material couple with high and low dielectric imaginary parts according to claim 1, characterized in that: The phase change material A is one of AgBiTe2, AgSbTe2, and In3SbTe2.

3. The infrared phase change material couple with high and low dielectric imaginary parts according to claim 1, characterized in that: The phase change material B is one of Ge3Sb4Te8, Ge3Sb2Te6, and GeTe4.

4. The infrared phase change material couple with high and low dielectric imaginary parts according to any one of claims 1-3, characterized in that, Its preparation method specifically includes the following steps: S1. Phase change material A is used as target A, and phase change material B is used as target B. In the magnetron sputtering coating system, target A and target B are installed at their respective target positions, and ZnS is used as the substrate. S2. Evacuate the sputtering chamber of the magnetron sputtering coating system until the vacuum level in the chamber reaches the set value, and then introduce high-purity Ar gas into the sputtering chamber until the gas pressure in the sputtering chamber reaches the starting gas pressure required for sputtering. S3. Using an RF power supply, adjust the power, target-substrate distance, working pressure and Ar gas flow rate of target A and target B, and sputter target A and target B on the substrate in sequence. Control the film thickness of target A and target B respectively during the sputtering process to obtain a double-layer thin film material. S4. Annealing is performed in a tube furnace with an Ar atmosphere to obtain a crystalline thin film material.

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