Reconfigurable infrared light absorption device based on scandium, antimony and tellurium
By using scandium-anti-tellurium tellurium phase change material in mid-infrared light absorption devices and writing to the grating bar directly through laser pulses, the problems of poor absorption effect and slow switching speed in the mid-infrared band in the prior art are solved, and the effects of high absorption and high switching speed are achieved.
Patent Information
- Application Number
- CN202510463671.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-14
- Publication Date
- 2025-06-13
AI Technical Summary
The prior art has poor light absorption effect in the mid-infrared band, and the switching speed of the metasurface devices based on germanium antimony tellurium is slow, making it difficult to meet the needs of high absorption and high switching speed.
Scandium antimony tellurium is used as the phase change material, and periodically arranged crystal Scandium antimony tellurium grating strips are written in the phase change layer through laser pulses to form a metasurface structure embedded in the amorphous, changing the light absorption bandwidth range of the device, and continuously tuning the absorption rate is achieved by adjusting the depth and period of the grating strips.
It significantly improves the switching speed of the device, can realize reversible phase change at the sub-nanosecond level, and improves the thermal stability of the device and the regulation ability of the absorption spectrum line, and is suitable for the high absorption and high switching speed requirements of the mid-infrared band.
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Figure CN120143324A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical fields of phase change materials and mid-infrared optical devices, and particularly to a reconfigurable infrared light absorption device based on scandium antimony telluride. Background Art
[0002] The control of electromagnetic waves is of great significance in scientific research and industrial applications. In recent years, optical metasurfaces composed of light-scattering nanostructures with engineered optical properties have solved challenging problems encountered in the regulation of electromagnetic waves by traditional optical devices. In addition to the parameters of the nanostructure units, the selection of suitable materials also plays an important role in metasurface design, which depends on the specific application and required characteristics of the metasurface, such as the working wavelength, polarization sensitivity, and loss level. Phase change materials can undergo rapid reversible switching between amorphous and crystalline states under the action of thermal pulses or laser pulses, and both phases can stably exist for decades. There are significant differences in the optical properties between the two phases before and after switching, which can directly affect the resonance of nanostructures and thus change the function of the device.
[0003] The mid-infrared band is usually 3–25 μm, and the short-wave mid-infrared (3-5 μm) and long-wave mid-infrared (8-14 μm) have important application values in many fields such as industry and medicine. The traditional phase change material germanium antimony telluride as a light absorber of metamaterials shows good light absorption effects in the visible and near-infrared ranges, but limited by the material bandgap, it does not show effective applications in the complete infrared light range, and limited by the crystallization speed of germanium antimony telluride, the switching speed of the metasurface device based on it is only dozens of nanoseconds. According to Kirchhoff's law, a perfect absorber is also a perfect radiator, and thermal radiation detection requires broadening the absorption bandwidth. There is an urgent need to find new phase change materials that meet high absorption in the mid-infrared band and have a high switching speed for perfect light absorbers in the mid-infrared band. Summary of the Invention
[0004] To overcome the above defects existing in the prior art, the present invention provides a reconfigurable infrared light absorption device based on scandium antimony telluride. Scandium antimony telluride has a crystallization speed at the sub-nanosecond level, which can significantly improve the switching speed of the device. By direct laser writing, rapid crystallization phase change of scandium antimony telluride can be induced in a specific area, and periodic grating bars with variable widths and depths are written in the phase change layer, so as to form a resonant infrared absorption system with the underlying metal mirror and change the light absorption bandwidth range of the device. In addition, the depth and width of the crystallized grating bars are continuously adjustable, so as to realize continuous tuning of the absorption rate peak; the crystallized grating bars can be erased by direct laser writing for amorphization, so as to restore the device to its original state and achieve reconstruction.
[0005] To achieve the above object, the technical solution adopted by the present invention is:
[0006] A reconfigurable mid-infrared light absorption device based on scandium antimony telluride phase change material. The device unit from top to bottom is a protective layer, a phase change layer, a dielectric layer, a reflective layer and a substrate in sequence. The phase change layer material is scandium antimony telluride with the chemical formula Sc x Sb 2- x Te 3 , where 0 ≤ x ≤ 2;
[0007] Write grating bars in the phase change layer.
[0008] The protective layer is used to prevent the phase change layer from oxidation or laser irradiation damage. The phase change layer is an amorphous film of Sc x Sb y Te 3 . The phase change layer and the dielectric layer are used to regulate the reflectivity of the device. The reflective layer is used to provide specular reflection.
[0009] Both the amorphous phase and the crystalline phase of the scandium antimony telluride are semiconductor properties. The amorphous phase is bonded by covalent bonds, and the crystalline phase is bonded by metal covalent bonds. Therefore, there are obvious differences in the light absorption rates of the two phases in the mid-infrared band. Scandium is used to reduce the nucleation randomness of antimony telluride, and the crystallization speed can reach the order of sub-nanoseconds. Scandium is used to increase the nucleation energy barrier of antimony telluride, and the thermal stability of the material is increased to above 150 °C. Both phases are non-volatile.
[0010] The material of the protective layer is any one of SiO 2 , ITO, and the thickness range is 5 - 30 nm. The content of scandium element in the phase change layer is adjustable, and the absorption spectral line of the device undergoes a blue shift with the increase of the scandium element content. The thickness t of the phase change layer ranges from 20 - 350 nm, and the bandwidth range of light absorption can be regulated by changing t. The material of the dielectric layer is any one of SiO 2 , ITO materials, and the thickness range is 100 - 300 nm. The material of the reflective layer is any one of Au, Pt, Ag, Al materials, and the thickness range is 50 - 300 nm. The material of the substrate is any one of SiO 2 , Si.
[0011] The preparation methods of the above materials include but are not limited to physical vapor deposition method PVD, chemical vapor deposition method CVD or atomic layer deposition method ALD.
[0012] Drive the phase change layer to crystallize by pulsed laser direct writing, and then write periodically arranged crystalline scandium antimony telluride grating bars to form a super-surface structure with crystalline scandium antimony telluride gratings embedded in the amorphous. In the mid-infrared band range, crystalline scandium antimony telluride has different optical dielectric constants from amorphous scandium antimony telluride, and can form a resonant cavity with the dielectric layer and the reflective layer to change the absorption spectral line range of the absorber.
[0013] The depth range d of the grating bars is 5 - 350 nm, and the absorption spectrum line of the device unit redshifts as d increases; the arrangement period p of the grating bars is 1 - 4 μm, and the absorption spectrum line of the device unit redshifts as d increases.
[0014] The depth range d of the grating bars is adjusted by controlling the power and pulse width of the laser pulse, where the power range is 20 mW to 200 mW and the pulse width range is 100 fs to 100 ms. The larger the selected power and pulse width, the larger d; the arrangement period p of the grating bars is adjusted by changing the relative position of the laser and the device.
[0015] Advantages of the present invention:
[0016] The present invention proposes a scandium antimony telluride phase change material for a reconfigurable mid-infrared light absorber. The doping of scandium elements can effectively reduce the nucleation randomness of antimony telluride, enabling reversible phase change between the amorphous phase and the crystalline phase within the sub-nanosecond range, far exceeding the tens of nanosecond phase change speed of the traditional phase change material germanium antimony telluride. Therefore, the switching speed of the device can be significantly improved; scandium elements can increase the nucleation energy barrier of antimony telluride, thereby raising the crystallization temperature of antimony telluride from ~70 °C to above 150 °C. Therefore, the thermal stability of the device can be effectively improved.
[0017] In the mid-infrared band range, there are obvious differences in the optical dielectric constants of the crystal and amorphous forms of scandium antimony telluride. Therefore, forming a structure with crystalline grating bars embedded in the amorphous can form a resonant cavity with the dielectric layer and the reflective layer. By changing the phase change depth and arrangement period of the grating bars, the absorption spectrum range of the absorber can be effectively adjusted. In addition, the depth and period of the grating bars can be continuously adjusted, so continuous tuning of the absorption spectrum range of the absorber can be achieved. The crystallized grating bars can be erased and made amorphous through direct laser pulse writing, thus restoring the device to its original state for reconfiguration.
[0018] The present invention proposes a scandium antimony telluride phase change material for a reconfigurable mid-infrared light absorber. The material composition range is relatively wide, and the device has various adjustment parameters, including the thickness of the phase change layer, the depth and period of the grating bars. Therefore, the absorber can tune a relatively wide absorption spectrum range, and the positions where the light absorption peak can be regulated include short-wave mid-infrared (3 - 5 μm) and long-wave mid-infrared (8 - 14 μm), which have broad prospects in thermal imaging, thermal radiation detection (such as night vision devices, meteorological satellites), especially in military applications. In addition, this band overlaps with the atmospheric window region and also has potential application prospects in fields relying on atmospheric transmission such as remote sensing, thermal imaging, and astronomical observations. Description of the Drawings
[0019] Figure 1 For Sc x Sb 2-x Te 3Simulated real and imaginary parts of the dielectric constant of the amorphous and crystalline phases of the phase change material.
[0020] Figure 2 Schematic diagram of the structure of the reconfigurable mid-infrared light absorption device proposed by the present invention.
[0021] Figure 3 Based on Sc x Sb 2-x Te 3 Simulated reflection spectra of the mid-infrared light absorption device based on the phase change material with the change of the thickness of the phase change layer.
[0022] Figure 4 Schematic diagram of the crystallization of the phase change layer along the grating bars of the mid-infrared light absorption device proposed by the present invention through laser driving.
[0023] Figure 5 Based on Sc x Sb 2-x Te 3 Simulated reflection spectra of the mid-infrared light absorption device based on the phase change material with the change of the depth range of the grating bars.
[0024] Figure 6 Based on Sc x Sb 2-x Te 3 Simulated reflection spectra of the mid-infrared light absorption device based on the phase change material with the change of the arrangement period of the grating bars. Detailed implementation manner
[0025] The present invention will be further described in detail below with reference to the accompanying drawings.
[0026] Figure 1 The left view shows the real part of the dielectric constant of the amorphous and crystalline phases of the Sc x Sb 2-x Te 3 phase change thin film, Figure 1 The right view shows the imaginary part of the dielectric constant of the amorphous and crystalline phases of the Sc x Sb 2-x Te 3 phase change thin film. The real and imaginary parts of the dielectric constant of its amorphous and crystalline phases show obvious differences.
[0027] Figure 2 The structural units of the device described above are, from top to bottom, a protective layer 101, a phase change layer 102, a dielectric layer 103, a reflective layer 104, and a substrate 105. The protective layer 101 is used to prevent oxidation of the phase change layer or surface damage during the laser-driven reconstruction process, etc.; the phase change layer 102 is Sc x Sb 2-x Te 3Amorphous thin film; the dielectric layer 103 is used to adjust the overall reflectivity of the device; the reflective layer 104 is used to achieve specular reflection.
[0028] Figure 3 For Sc-based x Sb 2-x Te 3 Reflection spectra of the mid-infrared light absorption device based on the phase change material varying with the thickness t of the amorphous layer. As the thickness of the phase change layer increases, the light absorption rate of the device at ~9.5 μm gradually increases. There are differences in the reflection spectra of the device when the thickness of the phase change layer is ≤200 nm and >200 nm. When the thickness is ≤200 nm, the reflection spectrum of the device will redshift as the thickness increases. When the thickness >200 nm, the light absorption rate of the device at the ~9.5 μm spectrum gradually increases, and when the thickness is 240 nm, the light absorption rate of the device at this spectrum reaches more than 80%.
[0029] Figure 4 In the device described above, the depth range d of the grating bars 106 is 5 - 350 nm, and the arrangement period p is 1 - 4 μm.
[0030] Figure 5 In the device unit, the arrangement period p of the grating bars 106 is 1 μm, and its reflection spectrum redshifts as the depth range d gradually increases. The light absorption rate of the device in the mid-wave atmospheric window band of 2 - 3 μm decreases as the depth d increases. The light absorption rate of the device with a crystallization region depth of 30 nm can reach 99% at a certain point in this band, showing a performance close to perfect absorption. When the depth d is in the range of 170 - 240 nm, the light absorption rate of the device in the long-wave atmospheric window band can reach more than 90%, and near-perfect absorption is achieved in the band range of 11 - 12 μm.
[0031] Figure 6 In the device unit, the depth d of the grating bars 106 is 240 nm. When the arrangement period p increases from 1 μm to 4 μm, its reflection spectrum gradually blueshifts, and the peak value of the light absorption rate of the device in the long-wave atmospheric window band decreases. The device with an arrangement period p of 1 μm shows near-perfect absorption at a wavelength of ~11.8 μm, and the devices with other period lengths show a light absorption rate of more than 90% in the wavelength range of 9 - 10 μm.
[0032] The following further illustrates the present invention with specific embodiments as examples.
[0033] Example 1
[0034] This example is a reconfigurable mid-infrared light absorption device based on Sc 0.4 Sb 1.6 Te 3 phase change material, and the specific implementation process is as follows:
[0035] Sc0.4 Sb 1.6 Te 3 The real and imaginary parts of the dielectric function curves of the amorphous and crystalline phases of the phase change material are as follows Figure 1 (a). Both the amorphous and crystalline phases are semiconductor in nature. The crystalline phase has a relatively smaller bandgap and thus has a relatively stronger light signal absorption effect. The switching speed between the two phases reaches the sub-nanosecond level, and both phases are non-volatile and can maintain a stable state at room temperature for decades.
[0036] Based on Sc 0.4 Sb 1.6 Te 3 The structural unit of the mid-infrared light absorption device based on the phase change material is as follows Figure 2 . From top to bottom, they are a protective layer 101, a phase change layer 102, a dielectric layer 103, a reflective layer 104, and a substrate 105. Both the protective layer 101 and the dielectric layer 103 are made of SiO 2 materials, with thicknesses of 20 nm and 230 nm respectively; the phase change layer 102 is made of Sc 0.4 Sb 2 Te 3 material, and the thickness variation range is 30 - 240 nm; the reflective layer 104 is made of Pt material with a thickness of 100 nm; the substrate 105 is made of Si material. The variation of the reflection spectrum of the device with the thickness of the amorphous thin film is as follows Figure 3 . As the thickness of the phase change layer 102 gradually increases, the light absorption rate of the device at the spectral line of ~9.5 μm gradually increases and reaches more than 80% at 240 nm.
[0037] A pulsed laser is used to write grating bars in the phase change layer 102 to drive crystallization in this area. The writing direction is along the y-axis direction, the writing period direction is along the x-axis direction, and the arrangement period p is ~1 μm; the power of the pulsed laser is 200 mW, the pulse width is ~500 ps, and the depth d of the grating bars is ~170 nm. The light absorption rate of the device at the spectral line of ~9.5 μm reaches more than 95%.
[0038] Example 2
[0039] This example is a reconfigurable mid-infrared light absorption device based on Sc 0.4 Sb 1.6 Te 3 phase change material. The specific implementation process is as follows
[0040] Sc 0.4 Sb 1.6 Te 3 The real and imaginary parts of the dielectric function curves of the amorphous and crystalline phases of the phase change material are as follows Figure 1As shown in (a). Both the amorphous phase and the crystalline phase are semiconductor properties. The crystalline phase has a relatively larger bandgap, so it has a relatively stronger light signal absorption effect. The switching speed between the two phases reaches the sub-nanosecond level, and both phases are non-volatile and can maintain a stable state at room temperature for decades.
[0041] Based on Sc 0.4 Sb 2 Te 3 The structural unit of the mid-infrared light absorption device of the phase change material is as Figure 2 shown. From top to bottom, they are the protective layer 101, the phase change layer 102, the dielectric layer 103, the reflective layer 104, and the substrate 105. Both the protective layer 101 and the dielectric layer 103 are made of SiO 2 materials, with thicknesses of 20 nm and 230 nm respectively; the phase change layer 102 is Sc 0.4 Sb 1.6 Te 3 material, and the thickness variation range is 30 - 240 nm; the reflective layer 104 is made of Pt material with a thickness of 100 nm; the substrate 105 is made of Si material. The variation of the reflection spectrum of the device with the thickness of the amorphous thin film is as Figure 3 shown. As the thickness of the phase change layer 102 gradually increases, the light absorption rate of the device at the spectral line ~9.5 μm gradually increases and reaches more than 80% at 240 nm.
[0042] Use pulsed laser to write grating bars in the phase change layer 102 to drive crystallization in this area. The writing direction is along the y-axis direction, the writing period direction is along the x-axis direction, and the arrangement period p is ~4 μm; the power of the pulsed laser is 200 mW, the pulse width is ~20 ms, and the depth d of the grating bar is ~240 nm. The light absorption rate of the device at the spectral line ~11.8 μm reaches ~100%.
Claims
1. A reconfigurable mid-infrared light absorption device based on scandium antimony telluride phase change material, characterized in that: The device unit is composed of a protective layer (101), a phase change layer (102), a dielectric layer (103), a reflective layer (104) and a substrate (105) from top to bottom. The phase change layer material is scandium antimony telluride, and its chemical formula is Sc x Sb 2-x Te3, where 0≤x≤2; The grating strips (106) are written into the side of the phase change layer (102) close to the protective layer (101).
2. The reconfigurable mid-infrared light absorption device based on scandium antimony telluride phase change material according to claim 1, characterized in that: The protective layer (101) is used to prevent the phase change layer from being oxidized or damaged by laser irradiation; the phase change layer (102) is Sc x Sb y Te3 amorphous film; the phase change layer (102) and the dielectric layer (103) are used to adjust the reflectivity of the device; and the reflective layer (104) is used to provide mirror reflection.
3. The reconfigurable mid-infrared light absorption device based on scandium antimony telluride phase change material according to claim 1, characterized in that: The amorphous phase and crystalline phase of the scandium antimony telluride are both semiconductor in nature, the amorphous phase is bonded by covalent bonds, and the crystalline phase is bonded by metallic covalent bonds; the scandium element is used to reduce the randomness of the nucleation of antimony telluride, and can achieve a crystallization speed of the sub-nanosecond order; the scandium element is used to increase the nucleation energy barrier of antimony telluride, so that the thermal stability of the material is increased to above 150°C, and both phases are non-volatile.
4. The reconfigurable mid-infrared light absorption device based on scandium antimony telluride phase change material according to claim 1, characterized in that: The material of the protective layer (101) is any one of SiO2 and ITO, and the thickness ranges from 5 to 30 nm; the scandium content of the phase change layer (102) is adjustable, and the absorption spectrum of the device blue-shifts as the scandium content increases; the thickness t of the phase change layer (102) is in the range of 20 to 350 nm, and the bandwidth range of light absorption can be adjusted by changing t; the material of the dielectric layer (103) is any one of SiO2 and ITO, and the thickness ranges from 100 to 300 nm; the material of the reflective layer (104) is any one of Au, Pt, Ag, and Al, and the thickness ranges from 50 to 300 nm; the material of the substrate (105) is any one of SiO2 and Si.
5. The reconfigurable mid-infrared light absorption device based on scandium antimony telluride phase change material according to claim 1, characterized in that: The phase change layer (102) is driven to crystallize by direct writing with a pulsed laser, and then periodically arranged crystalline scandium antimony telluride grating strips (106) are written to form a super surface structure in which the crystal grating strips are embedded in an amorphous material. In the mid-infrared band, the crystalline scandium antimony telluride has an optical dielectric constant different from that of the amorphous scandium antimony telluride, and can form a resonance cavity with the dielectric layer (103) and the reflective layer (104), thereby changing the absorption spectrum range of the absorber.
6. The reconfigurable mid-infrared light absorption device based on scandium antimony telluride phase change material according to claim 5, characterized in that: The depth range d of the grating strips (106) is 5-350 nm, and the absorption spectrum of the device unit is red-shifted as d increases; the arrangement period p of the grating strips (106) is 1-4 μm, and the absorption spectrum of the device unit is red-shifted as d increases.
7. The reconfigurable mid-infrared light absorption device based on scandium antimony telluride phase change material according to claim 5, characterized in that: The depth range d of the grating strips (106) is adjusted by controlling the power and pulse width of the laser pulse, wherein the power range is 20mW to 200mW, and the pulse width range is 100fs to 100ms, and the larger the selected power and pulse width, the larger d; the arrangement period p of the grating strips (106) is adjusted by changing the relative position of the laser and the device.