Ultra-wideband absorber and preparation method thereof

Abstract

The present application relates to the field of preparation technology. Specifically, an ultra-wideband absorber and a preparation method are disclosed. The ultra-wideband absorber includes a substrate, a first dielectric layer is provided on the substrate, a convex structure array is formed on the side of the first dielectric layer facing away from the substrate, and a first metal layer, a second dielectric layer, and a second metal layer are sequentially provided on the side of the convex structure array facing away from the substrate. The present invention achieves ultra-wideband, bidirectional, wide-angle, and efficient absorption in the visible to infrared band. Within the 400nm-4000nm band, the average absorption efficiency of the upper surface of the electromagnetic wave absorption structure is greater than 92%, and the average absorption of the lower surface is close to 85%. The angular tolerance is large, and when the incident angle is 60°, it can still maintain good bidirectional absorption performance, with an average absorption of greater than 92% on the upper surface and an average absorption of greater than 80% on the lower surface. The device has a simple structure, is convenient for large-scale and batch production, and is easy to integrate with optoelectronic devices. It has a wide range of applications in display, solar cells, thermophotovoltaics and other fields.

Description

Technical Field

[0001] The present application generally relates to the field of preparation technology, and in particular to an ultra-wideband absorber and a preparation method thereof. Background Art

[0002] Ultra-wideband absorbers in the visible-infrared band have important applications in green printing, new display technologies, photovoltaics, and other fields. In the display field, they can be used to form the black matrix on the color filter substrate of liquid crystal display panels, increasing contrast and preventing light leakage and color confusion. In the green printing field, they are used to achieve black, which is expected to replace highly polluting dyes / pigments and bring revolutionary changes to ink-free printing. In the photovoltaic field, they can be used to capture sunlight energy and achieve pollution-free power generation. They can also be used in stealth, electromagnetic shielding, and other applications. With the rapid development of micro-nanofabrication technology and near-field characterization and detection technology, high-efficiency absorption in the visible-infrared band (400nm-40000nm) has attracted the attention of academia and industry.

[0003] The currently publicly reported literature and patents have low light energy utilization rates, which are mainly manifested in: narrow absorption bandwidth, usually low absorption efficiency in certain bands (<70%), and inability to achieve ultra-wideband high-efficiency absorption. Summary of the Invention

[0004] In order to solve the technical problem in the prior art that the existing ultra-wideband absorbing devices have low absorption efficiency and cannot achieve ultra-wideband high-efficiency absorption, the present application provides an ultra-wideband absorber and a preparation method.

[0005] To achieve the above-mentioned invention objectives, this application adopts the following technical solutions:

[0006] According to a first aspect of an embodiment of the present application, an ultra-wideband absorber is provided, comprising a substrate, on which a first dielectric layer is disposed, wherein a protrusion structure array is formed on a side of the first dielectric layer facing away from the substrate, and a first metal layer, a second dielectric layer, and a second metal layer are sequentially disposed on a side of the protrusion structure array facing away from the substrate.

[0007] According to one embodiment of the present application, the height of the protruding structure in a cross section parallel to the thickness direction of the first dielectric layer ranges from 100 nm to 1600 nm.

[0008] According to one embodiment of the present application, the width of the protrusion structure in a cross section parallel to the thickness direction of the first dielectric layer is in the range of 100 nm to 350 nm.

[0009] According to one embodiment of the present application, the thickness of the first metal layer is in the range of 0 nm to 800 nm.

[0010] According to one embodiment of the present application, the thickness of the second dielectric layer is in the range of 50 nm to 250 nm.

[0011] According to one embodiment of the present application, the thickness of the second metal layer is in the range of 200 nm to 500 nm.

[0012] According to one embodiment of the present application, the ultra-wideband absorber absorbs light from the visible to infrared bands.

[0013] According to an embodiment of the present application, a third dielectric layer is provided on a side of the second metal layer facing away from the second dielectric layer.

[0014] According to an embodiment of the present application, a side of the third dielectric layer facing away from the second metal layer is a planar structure.

[0015] According to an embodiment of the present application, in the thickness direction of the substrate, the maximum distance between a side of the third dielectric layer facing away from the second metal layer and a side of the second metal layer facing away from the second dielectric layer is H, and H≤1600 nm.

[0016] According to one embodiment of the present application, the protrusion structure is a periodic array.

[0017] According to a second aspect of an embodiment of the present application, a method for preparing an ultra-wideband absorber is provided, comprising:

[0018] forming the first dielectric layer on the substrate;

[0019] forming the protrusion structure array on a side of the first dielectric layer facing away from the substrate by using nanoimprint technology or photolithography technology;

[0020] forming the first metal layer on the surface of the protrusion structure array using a first mask;

[0021] forming the second dielectric layer on the surface of the first metal layer using a second mask;

[0022] The second metal layer is formed on the surface of the second dielectric layer using a third mask.

[0023] According to one embodiment of the present application, wherein:

[0024] The hollowing dimension of the first mask is the sum of the thickness of the first metal layer and the width of the cross section of the protruding structure in the thickness direction of the substrate;

[0025] The hollowing dimension of the second mask is the sum of the hollowing dimension of the first mask and the thickness of the second dielectric layer;

[0026] The hollowing dimension of the third mask is the sum of the hollowing dimension of the second mask and the thickness of the second metal layer.

[0027] According to one embodiment of the present application, the method for preparing the ultra-wideband absorber further comprises:

[0028] A third dielectric layer is formed on the surface of the second metal layer.

[0029] According to one embodiment of the present application, the first metal layer and the second metal layer can be formed by electron beam evaporation, thermal evaporation or magnetron sputtering.

[0030] According to one embodiment of the present application, the second dielectric layer is formed by inductively coupled plasma chemical vapor deposition or atomic layer deposition.

[0031] According to a third aspect of an embodiment of the present application, a method for preparing an ultra-wideband absorber is provided, comprising:

[0032] forming the first dielectric layer on the substrate;

[0033] forming the protrusion structure array on a side of the first dielectric layer facing away from the substrate by using nanoimprint technology or photolithography technology;

[0034] forming a metal layer on the surface of the protrusion structure array, and etching the metal layer through a fourth mask to form the first metal layer;

[0035] forming a dielectric layer on the surface of the first metal layer, and etching the dielectric layer through a fifth mask to form the second dielectric layer;

[0036] A metal layer is formed on the surface of the second dielectric layer, and the metal layer is etched using a sixth mask to form a second metal layer.

[0037] According to an embodiment of the present application, the protrusion structure is a periodic array, and the hollowing dimension of the fourth mask is the difference between the array period of the protrusion structure, the thickness of the first metal layer, and the width of the cross section of the protrusion structure in the thickness direction of the substrate;

[0038] The hollowing dimension of the fifth mask is the difference between the hollowing dimension of the fourth mask and the thickness of the second dielectric layer;

[0039] The hollowing dimension of the sixth mask is the difference between the hollowing dimension of the fifth mask and the thickness of the second metal layer.

[0040] According to one embodiment of the present application, the etching may be a reactive ion etching technique.

[0041] As can be seen from the above technical solution, the advantages and positive effects of the ultra-wideband absorber and preparation method of the present application are: achieving ultra-wideband, bidirectional, wide-angle, and efficient absorption from the visible to infrared bands. Within the 400nm-4000nm band, the average absorption efficiency of the upper surface of the electromagnetic wave absorption structure is greater than 92%, and the average absorption of the lower surface is close to 85%. It has a large angular tolerance and can still maintain good bidirectional absorption performance at an incident angle of 60°, with an average absorption of greater than 92% on the upper surface and greater than 80% on the lower surface. The device has a simple structure, is easy to produce on a large scale, and is easily integrated with optoelectronic devices. It has a wide range of applications in display, solar cell, thermophotovoltaic and other fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0043] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0044] Figure 1 1 is a schematic diagram of the overall structure of an ultra-wideband absorber according to an exemplary embodiment (I).

[0045] Figure 2 2 is a schematic diagram of the overall structure of an ultra-wideband absorber according to an exemplary embodiment.

[0046] Figure 3 FIG. 1 is an absorption spectrum of an ultra-wideband absorber when electromagnetic waves are incident from the upper surface and the lower surface according to an exemplary embodiment.

[0047] Figure 4 FIG4 is a graph showing the relationship between absorption efficiency and wavelength of an ultra-wideband absorber when electromagnetic waves are incident on the upper surface at different incident angles according to an exemplary embodiment.

[0048] Figure 5 FIG. 4 is a graph showing the relationship between absorption efficiency and wavelength of an ultra-wideband absorber when electromagnetic waves are incident on the lower surface at different incident angles according to an exemplary embodiment.

[0049] Figure 6 3 is a coordinate diagram showing the effect of thickness variation of the first metal layer on the absorption spectrum of an ultra-wideband absorber when an electromagnetic wave is incident from the upper surface according to an exemplary embodiment.

[0050] Figure 73 is a coordinate diagram showing the effect of thickness variation of the first metal layer on the absorption spectrum of an ultra-wideband absorber when an electromagnetic wave is incident from the bottom surface according to an exemplary embodiment.

[0051] Figure 8 3 is a coordinate diagram showing the effect of thickness variation of the second metal layer on the absorption spectrum of an ultra-wideband absorber when an electromagnetic wave is incident from the upper surface according to an exemplary embodiment.

[0052] Figure 9 3 is a coordinate diagram showing the effect of thickness variation of the second metal layer on the absorption spectrum of an ultra-wideband absorber when an electromagnetic wave is incident from the bottom surface according to an exemplary embodiment.

[0053] Figure 10 3 is a coordinate diagram showing the effect of thickness variation of the second dielectric layer on the absorption spectrum of an ultra-wideband absorber when an electromagnetic wave is incident from the upper surface according to an exemplary embodiment.

[0054] Figure 11 3 is a coordinate diagram showing the effect of thickness variation of the second dielectric layer on the absorption spectrum of an ultra-wideband absorber when electromagnetic waves are incident from the bottom surface according to an exemplary embodiment.

[0055] Figure 12 1 is a coordinate diagram showing the effect of height variation of a protruding structure array on the absorption spectrum of an ultra-wideband absorber when an electromagnetic wave is incident from the upper surface according to an exemplary embodiment.

[0056] Figure 13 1 is a coordinate diagram showing the effect of height variation of a protruding structure array on the absorption spectrum of an ultra-wideband absorber when electromagnetic waves are incident from the bottom surface according to an exemplary embodiment.

[0057] Figure 14 1 is a coordinate diagram showing the effect of width variation of a protrusion structure array on the absorption spectrum of an ultra-wideband absorber when an electromagnetic wave is incident from the upper surface according to an exemplary embodiment.

[0058] Figure 15 1 is a coordinate diagram showing the effect of width variation of a protrusion structure array on the absorption spectrum of an ultra-wideband absorber when electromagnetic waves are incident from the bottom surface according to an exemplary embodiment.

[0059] Figure 16 FIG. 1 is an absorption spectrum of an ultra-wideband absorber when an electromagnetic wave is incident at 0° from the upper surface when a third dielectric layer is provided according to an exemplary embodiment.

[0060] Figure 17 FIG. 1 is an absorption spectrum of an ultra-wideband absorber when an electromagnetic wave is incident at 0° from the bottom surface when a third dielectric layer is provided according to an exemplary embodiment.

[0061] Figure 18 1 is a schematic diagram of the processing steps of a method for preparing an ultra-wideband absorber according to an exemplary embodiment (I).

[0062] Figure 19 Schematic diagram (2) of the processing steps of a method for preparing an ultra-wideband absorber according to an exemplary embodiment.

[0063] Figure 20 Schematic diagram (3) of the processing steps of a method for preparing an ultra-wideband absorber according to an exemplary embodiment.

[0064] Figure 21 Schematic diagram (four) of the processing steps of a method for preparing an ultra-wideband absorber according to an exemplary embodiment.

[0065] Figure 22 Schematic diagram (V) of the processing steps of a method for preparing an ultra-wideband absorber according to an exemplary embodiment.

[0066] The description of the accompanying drawings is as follows:

[0067] 1. Substrate; 2. First dielectric layer; 21. Protruding structure; 3. First metal layer; 4. Second dielectric layer; 5. Second metal layer; 6. Third dielectric layer; 7. First mask; 8. Second mask; 9. Third mask; 10. Fourth mask; 11. Fifth mask; 12. Sixth mask. DETAILED DESCRIPTION

[0068] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0069] It should be noted that, in the specification and claims of this application and the above-mentioned drawings, relational terms such as "first" and "second" are merely used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or specific order or precedence between these entities or operations. It should be understood that the terms used in this manner are interchangeable where appropriate, so that the embodiments of the present application described herein can, for example, be implemented in an order other than those illustrated or described herein.

[0070] Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, or any other variants thereof, are intended to encompass non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also includes other elements not expressly listed or that are inherent to such process, method, article, or apparatus. For example, a process, method, system, product, or apparatus that includes a list of steps or units is not necessarily limited to those steps or units expressly listed but may include other steps or units not expressly listed or that are inherent to such process, method, product, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a . . . ." does not preclude the presence of additional identical elements in the process, method, article, or apparatus that includes the element.

[0071] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used herein to describe the spatial positional relationship of a device or feature to other devices or features as shown in the figures. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figures. For example, if the device in the drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0072] In order to keep the following description of the embodiments of the present disclosure clear and concise, the present disclosure omits detailed descriptions of known functions and known components.

[0073] The embodiment of the present disclosure provides an ultra-wideband absorber, the structure of which is shown in FIG. Figure 1-Figure 2 As shown in the figure, it includes a substrate 1, a first dielectric layer 2 is provided on the substrate 1, an array of protrusion structures 21 is formed on the side of the first dielectric layer 2 facing away from the substrate 1, and a first metal layer 3, a second dielectric layer 4 and a second metal layer 5 are sequentially provided on the side of the array of protrusion structures 21 facing away from the substrate 1.

[0074] It should be noted that the upper surface of the ultra-wideband absorber in the embodiment of the present disclosure is the side of the second metal layer 5 away from the second dielectric layer 4 , and the lower surface of the ultra-wideband absorber is the side of the substrate 1 away from the first dielectric layer 2 .

[0075] The above-mentioned configuration enables the ultra-wideband absorber to achieve bidirectional wide-angle and efficient absorption from visible light to infrared bands, and the bandwidth of the ultra-wideband absorber can reach 3600nm. Figure 1 and Figure 3 As shown in the , within the 400nm-4000nm band, the average absorption efficiency of the upper surface of the ultra-wideband absorber is about 92%, and the average absorption of the lower surface is close to 85%, with high light energy utilization. The absorption performance in the visible-infrared band has high absorption efficiency, bidirectionality, and wide angle.

[0076] Furthermore, the adjacent second metal layers 5 on two adjacent arrays of protruding structures 21 abut against each other on their adjacent surfaces. In this case, after the first metal layer 3, second dielectric layer 4, and second metal layer 5 are sequentially arranged on the adjacent arrays of protruding structures 21, the surface of the first dielectric layer 2 facing away from the substrate 1 is completely covered by the first metal layer 3, second dielectric layer 4, and second metal layer 5, respectively, resulting in a better absorption effect.

[0077] Reference Figure 1 and Figure 4 As described in , when electromagnetic waves are incident from the top surface, when the incident angles are 0°, 15°, 30°, 45°, and 60°, the average absorption efficiency of the absorbing structure is 92%, 92%, 93%, 94%, and 90%, respectively. Figure 1 and Figure 5 As described in the , when electromagnetic waves are incident from the bottom surface, when the incident angles are 0°, 15°, 30°, 45°, and 60°, the average absorption efficiency of the ultra-wideband absorber is 81%, 82%, 85%, 93%, and 96%, respectively. Therefore, the ultra-wideband absorber of the present application has a large angular tolerance and can still maintain good bidirectional absorption performance at an incident angle of 60°, with an average absorption of greater than 92% on the upper surface and greater than 80% on the lower surface. Therefore, the structure of the present invention has significant advantages in specific applications such as stealth, thermal emission, light display, thermophotovoltaics, and solar cells.

[0078] Specifically, the term "ultra-wideband" in this application refers to electromagnetic waves from the visible to infrared range. "Bidirectional" refers to electromagnetic waves incident from both the top and bottom surfaces of an ultra-wideband absorbing structure placed horizontally. "Wide-angle" refers to an incident angle within a ±60° range when the ultra-wideband bidirectional wide-angle absorbing structure is placed horizontally.

[0079] Reference Figure 1-Figure 2Furthermore, the raised structures 21 are formed on the first dielectric layer 2 via nanoimprinting or photolithography. This can be achieved by imprinting or photolithographically forming an array of raised structures 21 on the upper surface of the first dielectric layer 2, combined with coating technology. This facilitates large-scale, batch production and is easily integrated with optoelectronic devices, finding widespread application in fields such as displays, solar cells, and thermophotovoltaics. Specifically, the structure of the ultra-wideband absorber can trap electromagnetic waves, which are absorbed by the multilayer metal-dielectric composite micro-nanostructure, achieving broadband and wide-angle efficient absorption.

[0080] Furthermore, the material of the substrate 1 can be polyethylene terephthalate, polymethyl methacrylate, quartz, UV resin, polycarbonate or polydimethylsiloxane, silicon dioxide, aluminum dioxide, etc.

[0081] Furthermore, the first dielectric layer 2 and the second dielectric layer 4 can both be made of silicon dioxide or aluminum dioxide.

[0082] Furthermore, the first metal layer 3 , the second dielectric layer 4 and the second metal layer 5 are all layered structures with uniform thickness, thereby ensuring the absorption effect of electromagnetic waves.

[0083] Specifically, the thickness of the substrate 1 and the first dielectric layer 2 is not limited in this application, and those skilled in the art can select substrates 1 and first dielectric layers 2 of different thicknesses according to needs and other conditions.

[0084] Reference Figure 1-Figure 2 Furthermore, the first metal layer 3 and the second metal layer 5 can both be nickel, chromium or titanium.

[0085] Furthermore, the thickness of the first metal layer 3 is in the range of 0 nm to 800 nm. Optionally, the thickness of the first metal layer 3 is 300 nm. Figure 1 and Figure 6 When electromagnetic waves are incident from the top surface, the absorption performance of the ultra-wideband absorber slightly decreases within the 1000nm-1700nm wavelength range when the thickness of the first metal layer 3 varies from 0nm to 800nm, while the absorption performance in the 2000nm-4000nm band is significantly improved. When the thickness of the first metal layer 3 is 0nm, 200nm, 400nm, 600nm, and 800nm, the average absorption efficiency of the ultra-wideband absorber is 89%, 92%, 92%, 92%, and 92%, respectively. Therefore, when electromagnetic waves are incident from the top surface, the first metal layer 3 improves the average absorption efficiency of the ultra-wideband absorber in the 400nm-4000nm band.

[0086] Reference Figure 1 and Figure 7As shown in the figure, when electromagnetic waves are incident from the bottom surface, when the thickness of the first metal layer 3 is in the range of 0nm–800nm, the absorption performance of the ultra-wideband absorber at wavelengths of 400nm–1600nm is slightly reduced, while the absorption performance in the 1600nm–4000nm band is improved. When the thickness of the first metal layer 3 is 0nm, 200nm, 400nm, 600nm, and 800nm, the average absorption efficiency of the ultra-wideband absorber is 75%, 81%, 79%, 77%, and 75%, respectively. Therefore, when electromagnetic waves are incident from the bottom surface, selecting an appropriate thickness of the first metal layer 3 improves the average absorption efficiency of the ultra-wideband absorber in the 400nm–400nm band. Overall, the thickness of the first metal layer 3 has a regulatory effect on the device's bandwidth and absorption efficiency. When the thickness of the first metal layer 3 is 300 nm, the absorption efficiency of electromagnetic waves when incident from the upper surface and from the lower surface is better. Therefore, in the embodiment of the present disclosure, the thickness of the first metal layer 3 is 300 nm.

[0087] Furthermore, the thickness of the second metal layer 5 is in the range of 200nm-500nm. Optionally, the thickness of the second metal layer 5 is 300nm. Figure 1 and Figure 8 When electromagnetic waves are incident from the top surface, the absorption performance of the ultra-wideband absorber in the 1250nm-4000nm band is improved when the thickness of the second metal layer 5 varies from 200nm to 500nm. When the thickness of the second metal layer 5 is 0nm, 100nm, 200nm, 300nm, 400nm, and 500nm, the average absorption efficiency of the ultra-wideband absorber is 72%, 82%, 85%, 92%, 95%, and 95%, respectively. Therefore, when electromagnetic waves are incident from the top surface, the second metal layer 5 improves the absorption performance of the ultra-wideband absorber in the 400nm-4000nm band.

[0088] Reference Figure 1 and Figure 9As shown in the figure, when electromagnetic waves are incident from the bottom surface, when the thickness of the second metal layer 5 varies from 200nm to 500nm, the second metal layer 5 improves the absorption performance of the ultra-wideband absorber in the 1500nm to 4000nm band. When the thickness of the second metal layer 5 is 0nm, 100nm, 200nm, 300nm, 400nm, and 500nm, the average absorption efficiency of the ultra-wideband absorber is 67%, 74%, 77%, 81%, 80%, and 79%, respectively. It can be seen that when electromagnetic waves are incident from the bottom surface, the second metal layer 5 improves the absorption performance of the ultra-wideband absorber in the 400nm to 4000nm band. Overall, the thickness of the second metal layer 5 has a regulatory effect on the bandwidth and absorption efficiency of the device. When the second metal layer 5 is 300nm thick, the absorption efficiency is better when electromagnetic waves are incident from both the top and bottom surfaces. Therefore, the thickness of the second metal layer 5 is 300nm in the embodiment of the present disclosure.

[0089] Furthermore, the thickness of the second dielectric layer 4 is in the range of 50 nm to 250 nm. Optionally, the thickness of the second dielectric layer 4 is 200 nm. Figure 10 When electromagnetic waves are incident from the top surface, the absorption performance of the ultra-wideband absorber in the 2000nm-3250nm band decreases slightly when the thickness of the second dielectric layer 4 varies within the range of 50nm-250nm, while the absorption performance in the 3250nm-4000nm band improves. When the thickness of the second dielectric layer 4 is 0nm, 50nm, 100nm, 150nm, 200nm, and 250nm, the average absorption efficiency of the ultra-wideband absorber is 92%, 93%, 93%, 93%, 92%, and 91%, respectively. Therefore, when electromagnetic waves are incident from the top surface, the second dielectric layer 4 improves the absorption performance of the ultra-wideband absorber in the 400nm-4000nm band.

[0090] Reference Figure 1 and Figure 11As shown in the figure, when electromagnetic waves are incident from the bottom surface, the absorption performance in the 400nm-1200nm and 1500nm-4000nm bands is improved when the thickness of the second dielectric layer 4 varies within the range of 50nm-250nm. When the thickness of the second dielectric layer 4 is 0nm, 50nm, 100nm, 150nm, 200nm, and 250nm, the average absorption efficiency of the ultra-wideband absorber is 65%, 72%, 77%, 79%, 81%, and 81%, respectively. Therefore, when electromagnetic waves are incident from the bottom surface, the second dielectric layer 4 improves the absorption performance of the ultra-wideband absorber in the 400nm-4000nm band. Overall, the thickness of the second dielectric layer 4 has a regulatory effect on the device's bandwidth and absorption efficiency. Furthermore, when the second dielectric layer 4 is 200nm thick, the absorption efficiency is better when electromagnetic waves are incident from both the top and bottom surfaces. Therefore, the thickness of the second dielectric layer 4 is 200nm in the disclosed embodiment.

[0091] Furthermore, the shape of the protruding structure 21 can be a semi-ellipsoid, a cone, a truncated cone, a triangular pyramid or a quadrangular pyramid, etc. Those skilled in the art can set the shape of the protruding structure 21 as required according to processing convenience and actual needs.

[0092] Furthermore, the array of protrusion structures 21 may be a periodic structure or a non-periodic structure.

[0093] Specifically, the array of protruding structures 21 can be arranged in a rectangular, square, triangle, rhombus, parallelogram, hexagon, etc. The array of protruding structures 21 in the embodiment of the present disclosure is arranged in a periodic square.

[0094] Furthermore, the height of the protrusion structure 21 in the cross section parallel to the thickness direction of the first dielectric layer 2 is in the range of 100 nm to 1600 nm. Optionally, the height of the protrusion structure 21 in the cross section parallel to the thickness direction of the first dielectric layer 2 is 400 nm. Figure 1 and Figure 12 As shown in the figure, when electromagnetic waves are incident from the top surface, the absorption performance of the ultra-wideband absorber in the 400nm-4000nm band is improved when the height of the array of protrusion structures 21 varies within the range of 100nm-1600nm. When the height of the array of protrusion structures 21 is 100nm, 400nm, 700nm, 1000nm, 1300nm, and 1600nm, the average absorption efficiency of the ultra-wideband absorber is 85%, 92%, 94%, 95%, 97%, and 98%, respectively. Therefore, when electromagnetic waves are incident from the top surface, the height of the array of protrusion structures 21 improves the absorption performance of the ultra-wideband absorber in the 400nm-4000nm band.

[0095] Reference Figure 1 and Figure 13 As shown in the figure, when electromagnetic waves are incident from the bottom surface, the absorption performance of the ultra-wideband absorber in the 400nm-4000nm band is improved when the height of the array of protrusion structures 21 varies within the range of 100nm-1600nm. When the height of the array of protrusion structures 21 is 100nm, 400nm, 700nm, 1000nm, 1300nm, and 1600nm, the average absorption efficiency of the ultra-wideband absorber is 75%, 81%, 82%, 83%, 84%, and 84%, respectively. Therefore, when electromagnetic waves are incident from the bottom surface, the height of the array of protrusion structures 21 improves the absorption performance of the structure in the 400nm-4000nm band. In summary, the height of the array of raised structures 21 regulates the bandwidth and absorption efficiency of the device, and when the height of the array of raised structures 21 is 400 nm, the absorption efficiency of electromagnetic waves is better when incident from the upper surface and from the lower surface. Therefore, the height of the array of raised structures 21 in the embodiment of the present disclosure is 400 nm.

[0096] Furthermore, the width of the protrusion structure 21 in the cross section parallel to the thickness direction of the first dielectric layer 2 is in the range of 100 nm to 350 nm. Optionally, the width of the protrusion structure 21 in the cross section parallel to the thickness direction of the first dielectric layer 2 is 350 nm. Figure 1 、 Figure 14 and Figure 15 As shown, in the case of a periodic array of the protrusion structures 21, when the widths of the cross sections of the protrusion structures 21 parallel to the thickness direction of the first dielectric layer 2 are 100 nm, 150 nm, 200 nm, 250 nm, 300 nm and 350 nm respectively, when the electromagnetic wave is incident from the upper surface, the average absorption efficiency of the ultra-wideband absorber is 74%, 78%, 81%, 85%, 88% and 91% respectively; when the electromagnetic wave is incident from the lower surface, the average absorption efficiency of the ultra-wideband absorber is 73%, 74%, 75%, 76%, 77% and 80% respectively. It can be seen that the width of the cross section of the protrusion structure array 21 parallel to the thickness direction of the first dielectric layer 2 plays a role in regulating the absorption efficiency of the upper surface. When the width of the protrusion structure array 21 is 350nm, that is, the gap between the bottoms of the two second metal layers on two adjacent protrusion structures 21 is 0nm, the absorption efficiency of the upper and lower surfaces of the ultra-wideband absorber is the highest; when the width of the cross-section of the protrusion structure array 21 parallel to the thickness direction of the first dielectric layer 2 is less than 350nm, that is, the gap between the bottoms of the two second metal layers on two adjacent protrusion structures 21 is greater than 0nm, the absorption efficiency of the upper and lower surfaces of the ultra-wideband absorber decreases.

[0097] Reference Figure 1 and Figure 2A third dielectric layer 6 is provided on the side of the second metal layer 5 facing away from the second dielectric layer 4. The third dielectric layer 6 can improve the absorption efficiency and protect the structure of the ultra-wideband absorber, making it easier to integrate with other devices.

[0098] Optionally, the third dielectric layer 6 may be silicon dioxide or aluminum dioxide.

[0099] Furthermore, the side of the third dielectric layer 6 facing away from the second metal layer 5 is a planar structure. By setting the side of the third dielectric layer 6 facing away from the substrate 1 as a planar structure, the third dielectric layer 6 can protect other components of the ultra-wideband absorber, making it easier to integrate the ultra-wideband absorber with other components.

[0100] Optionally, in the thickness direction of the substrate 1, the maximum distance between the side of the third dielectric layer 6 facing away from the second metal layer 5 and the side of the second metal layer 5 facing away from the second dielectric layer 4 is H, where H is ≤ 1600 nm. Optionally, the maximum distance between the side of the third dielectric layer 6 facing away from the second metal layer 5 and the side of the second metal layer 5 facing away from the second dielectric layer 4 is 400 nm or 1400 nm.

[0101] Combine Figure 16 and Figure 17 As shown, when the thickness of the third dielectric layer 6 is 0 nm, 200 nm, 400 nm, 600 nm, 800 nm, 1000 nm, 1200 nm, 1400 nm and 1600 nm, respectively, when the electromagnetic wave is incident from the upper surface, the average absorption efficiency of the ultra-wideband absorber is 92%, 92%, 93%, 90%, 86%, 86%, 90%, 93% and 91%, respectively; when the electromagnetic wave is incident from the lower surface, the average absorption efficiency of the ultra-wideband absorber is 81%, 78%, 79%, 80%, 80%, 79%, 79%, 79% and 79%, respectively. When the third dielectric layer 6 faces away from the second metal layer 5, and the maximum distance H between it and the side of the second metal layer 5 facing away from the first dielectric layer 2 is 400 nm and 1400 nm, respectively, the average absorption efficiency of the ultra-wideband absorber is 93% when electromagnetic waves are incident from the top surface. In this case, the average absorption efficiency of the ultra-wideband absorber is slightly improved when electromagnetic waves are incident from the top surface. It can be seen that the provision of the third dielectric layer 6 not only protects the second metal layer 5 and facilitates integration with other devices, but also improves the absorption efficiency when electromagnetic waves are incident from the top surface.

[0102] Reference Figures 1-19 The present disclosure also provides a method for preparing an ultra-wideband absorber, comprising:

[0103] forming the first dielectric layer 2 on the substrate 1;

[0104] The array of protrusion structures 21 is formed on the side of the first dielectric layer 2 facing away from the substrate 1 by using nanoimprint technology or photolithography technology;

[0105] Using a first mask 7 to form the first metal layer 3 on the surface of the array of protrusion structures 21;

[0106] forming the second dielectric layer 4 on the surface of the first metal layer 3 using a second mask 8;

[0107] The second metal layer 5 is formed on the surface of the second dielectric layer 4 using a third mask 9 .

[0108] Through simple nanoimprinting or lithography technology, combined with coating and deposition technology, it can be prepared in large quantities, conveniently and quickly mass-produced and put on the market.

[0109] Furthermore, the hollowing dimension of the first mask 7 is the sum of the thickness of the first metal layer 3 and the width of the cross section of the protruding structure 21 in the thickness direction of the substrate 1;

[0110] The hollowing dimension of the second mask 8 is the sum of the hollowing dimension of the first mask 7 and the thickness of the second dielectric layer 4;

[0111] The hollowing dimension of the third mask 9 is the sum of the hollowing dimension of the second mask 8 and the thickness of the second metal layer 5 .

[0112] Reference Figure 18-19 Specifically, the first dielectric layer 2 is provided on the substrate 1 by coating with photoresist; the first metal layer 3 and the second metal layer 5 can be formed by electron beam evaporation, thermal evaporation or magnetron sputtering; the second dielectric layer 4 is formed by inductively coupled plasma chemical vapor deposition or atomic layer deposition. The ultra-wideband absorber provided in this application is formed by the above method, without the need to adopt the existing electron beam lithography / ion beam lithography, etching and other processes. The production cost is low, it is convenient for large-scale and batch production, and it is easy to integrate with optoelectronic devices. It is expected to be widely used in the fields of display, printing, photovoltaics, etc. For example, in the display field, it can be used to form the black matrix on the color filter substrate of the liquid crystal display panel. In the field of green printing, it is expected to replace heavily polluting dyes / pigments to produce black. In the photovoltaic field, it can be used to capture sunlight energy. It can also be used for stealth, electromagnetic shielding, etc.

[0113] During the manufacturing process, a first dielectric layer 2 is deposited on a substrate 1, and the first dielectric layer 2 may be silicon dioxide or aluminum dioxide; a nanoimprinting technique or a photolithography technique is used to form an array of protrusion structures 21 on the side of the first dielectric layer 2 facing away from the substrate 1, wherein the array of protrusion structures 21 may be a periodic array or a non-periodic array; a first metal layer 3 may be formed on the surface of the array of nano-protrusion structures 21 of the first dielectric layer 2 by electron beam evaporation, thermal evaporation or magnetron sputtering using a first mask 7, and the first metal layer 3 may be nickel, chromium, titanium or other metals; a second dielectric layer 4 may be formed on the surface of the first metal layer 3 by inductively coupled plasma chemical vapor deposition or atomic layer deposition using a second mask 8, and the second dielectric layer 4 may be silicon dioxide or aluminum dioxide; a third mask 9 may be used to form a second metal layer 5 on the surface of the second dielectric layer 4 by electron beam evaporation, thermal evaporation or magnetron sputtering, and the second metal layer 5 may be nickel, chromium, titanium or other metals.

[0114] Specifically, the hollowing scale of the first mask 7 is the sum of the width of the protruding structure 21 in the cross section parallel to the thickness direction of the substrate 1 and the thickness of the first metal layer 3; the hollowing scale of the second mask 8 is the sum of the hollowing scale of the first mask 7 and the thickness of the second dielectric layer 4; the hollowing scale of the third mask 9 is the sum of the hollowing scale of the first mask 7 and the thickness of the second dielectric layer 4.

[0115] Combine Figure 2 Furthermore, the method for preparing the ultra-wideband absorber of the present application further includes forming a third dielectric layer 6 on the surface of the second metal layer 5. The third dielectric layer 6 may be silicon dioxide or aluminum dioxide and may be formed on the second metal layer 5 by inductively coupled plasma chemical vapor deposition or atomic layer deposition. The third dielectric layer 6 protects other components of the ultra-wideband absorber, facilitating integration of the ultra-wideband absorber with other components.

[0116] Further, refer to Figure 1-Figure 22 As shown, the embodiment of the present disclosure also provides a method for preparing an ultra-wideband absorber, comprising:

[0117] forming the first dielectric layer 2 on the substrate 1;

[0118] The array of protrusion structures 21 is formed on the side of the first dielectric layer 2 facing away from the substrate 1 by using nanoimprint technology or photolithography technology;

[0119] forming a metal layer on the surface of the array of protruding structures 21, and etching the metal layer through a fourth mask 10 to form the first metal layer 3;

[0120] forming a dielectric layer on the surface of the first metal layer 3, and etching the dielectric layer through a fifth mask 11 to form the second dielectric layer 4;

[0121] A metal layer is formed on the surface of the second dielectric layer 4 , and the metal layer is etched using a sixth mask 12 to form a second metal layer 5 .

[0122] Reference Figure 20-22 During the manufacturing process, a first dielectric layer 2 is deposited on a substrate 1; an array of raised structures 21 is formed on the side of the first dielectric layer 2 facing away from the substrate 1 using nanoimprint technology or photolithography technology; a metal layer is formed on the surface of the array of raised structures 21 of the first dielectric layer 2. The metal of the metal layer can be nickel, chromium, titanium, etc., and the metal layer is etched using a fourth mask 10 to form a first metal layer 3; a dielectric layer is formed on the surface of the first metal layer 3. The dielectric layer can be silicon dioxide or aluminum dioxide. The dielectric layer is etched using a fifth mask 11 to form a second dielectric layer 4; a metal layer is formed on the surface of the second dielectric layer 4. The metal of the metal layer can be nickel, chromium, titanium, etc., and the metal layer is etched using a sixth mask 12 to form a second metal layer 5.

[0123] Furthermore, the raised structures 21 form a periodic array, and the hollowing dimension of the fourth mask 10 is the difference between the array period of the raised structures 21, the thickness of the first metal layer 3, and the width of the cross section of the raised structures 21 in the thickness direction of the substrate 1; the hollowing dimension of the fifth mask 11 is the difference between the hollowing dimension of the fourth mask 10 and the thickness of the second dielectric layer 4; and the hollowing dimension of the sixth mask 12 is the difference between the hollowing dimension of the fifth mask 11 and the thickness of the second metal layer 5. Specifically, the array period of the raised structures 21 can be selected based on actual needs and other circumstances.

[0124] Furthermore, the etching may be a reactive ion etching technique, or other etching methods in the prior art.

[0125] It should be noted that the ultra-wideband absorber provided in this application can be applied to many optoelectronic fields, such as solar cells, thermophotovoltaics, stealth, etc. It can provide a solution for achieving black in ink-free printing, and can also be used as a black matrix in the display field to improve the contrast of the image displayed by the display panel.

[0126] The above description is only a preferred embodiment of the present application and is not intended to limit the present invention. It should be pointed out that for ordinary technicians in this field, without departing from the concept of the present invention, they can also make several modifications and improvements, such as expanding from a cone structure array to a triangular pyramid or quadrangular pyramid structure array, changing the arrangement of the array, optimizing the period, height, and width of the cone structure array, changing the coating material and coating thickness, etc., so as to obtain a wider bandwidth and angular tolerance, all of which fall within the scope of protection of the present invention.

[0127] The general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application are intended to be included within the scope of protection of this application. Therefore, this application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features of this application.

Claims

1. An ultra-wideband absorber, characterized in that: The invention comprises a substrate, a first dielectric layer is provided on the substrate, a convex structure array is formed on a side of the first dielectric layer facing away from the substrate, and a first metal layer, a second dielectric layer and a second metal layer are sequentially provided on a side of the convex structure array facing away from the substrate; The adjacent second metal layers on the adjacent two protrusion structure arrays are in contact with each other at their respective sides; The shape of the protrusion structure is a semi-ellipsoid, a cone, a truncated cone, a triangular pyramid or a quadrangular pyramid; In the wavelength range of 400nm-4000nm, the average absorption efficiency of the upper surface of the ultra-wideband absorber is 92%, and the average absorption efficiency of the lower surface is 81%.

2. The ultra-wideband absorber according to claim 1, wherein The height of the protruding structure in a cross section parallel to the thickness direction of the first dielectric layer ranges from 100 nm to 1600 nm.

3. The ultra-wideband absorber according to claim 1, wherein The width of the protrusion structure in a cross section parallel to the thickness direction of the first dielectric layer ranges from 100 nm to 350 nm.

4. The ultra-wideband absorber according to claim 1, wherein The thickness of the first metal layer is greater than 0 nm and less than or equal to 800 nm.

5. The ultra-wideband absorber according to claim 1, wherein The thickness of the second dielectric layer is in the range of 50 nm to 250 nm.

6. The ultra-wideband absorber according to claim 1, wherein The thickness of the second metal layer is in the range of 200 nm to 500 nm.

7. The ultra-wideband absorber according to claim 1, wherein The ultra-wideband absorber absorbs light from the visible to infrared wavelengths.

8. The ultra-wideband absorber according to claim 1, wherein A third dielectric layer is provided on a side of the second metal layer facing away from the second dielectric layer.

9. The ultra-wideband absorber according to claim 8, wherein A side of the third dielectric layer facing away from the second metal layer is a planar structure.

10. The ultra-wideband absorber according to claim 8, wherein In the thickness direction of the substrate, the maximum distance between a side of the third dielectric layer facing away from the second metal layer and a side of the second metal layer facing away from the second dielectric layer is H, where H is less than or equal to 1600 nm.

11. The ultra-wideband absorber according to claim 1, wherein The protrusion structure is a periodic array.

12. A method for preparing an ultra-wideband absorber according to any one of claims 1 to 11, characterized in that: include: forming the first dielectric layer on the substrate; forming the protrusion structure array on a side of the first dielectric layer facing away from the substrate by using nanoimprint technology or photolithography technology; forming the first metal layer on the surface of the protrusion structure array using a first mask; forming the second dielectric layer on the surface of the first metal layer using a second mask; The second metal layer is formed on the surface of the second dielectric layer using a third mask.

13. The method for preparing an ultra-wideband absorber according to claim 12, wherein: The hollowing dimension of the first mask is the sum of the thickness of the first metal layer and the width of the cross section of the protruding structure in the thickness direction of the substrate; The hollowing dimension of the second mask is the sum of the hollowing dimension of the first mask and the thickness of the second dielectric layer; The hollowing dimension of the third mask is the sum of the hollowing dimension of the second mask and the thickness of the second metal layer.

14. The method for preparing an ultra-wideband absorber according to claim 12, wherein: The preparation method of the ultra-wideband absorber further includes: A third dielectric layer is formed on the surface of the second metal layer.

15. The method for preparing an ultra-wideband absorber according to claim 12, wherein: The first metal layer and the second metal layer can be formed by electron beam evaporation, thermal evaporation or magnetron sputtering.

16. The method for preparing an ultra-wideband absorber according to claim 12, wherein: The second dielectric layer is formed by inductively coupled plasma chemical vapor deposition or atomic layer deposition.

17. A method for preparing an ultra-wideband absorber according to any one of claims 1 to 11, characterized in that: include: forming the first dielectric layer on the substrate; forming the protrusion structure array on a side of the first dielectric layer facing away from the substrate by using nanoimprint technology or photolithography technology; forming a metal layer on the surface of the protrusion structure array, and etching the metal layer through a fourth mask to form the first metal layer; forming a dielectric layer on the surface of the first metal layer, and etching the dielectric layer through a fifth mask to form the second dielectric layer; A metal layer is formed on the surface of the second dielectric layer, and the metal layer is etched using a sixth mask to form a second metal layer.

18. The method for preparing an ultra-wideband absorber according to claim 17, wherein: The protrusion structure is a periodic array, and the hollowing dimension of the fourth mask is the difference between the array period of the protrusion structure, the thickness of the first metal layer, and the width of the cross section of the protrusion structure in the thickness direction of the substrate; The hollowing dimension of the fifth mask is the difference between the hollowing dimension of the fourth mask and the thickness of the second dielectric layer; The hollowing dimension of the sixth mask is the difference between the hollowing dimension of the fifth mask and the thickness of the second metal layer.

19. The method for preparing an ultra-wideband absorber according to claim 17, wherein: The etching may be performed using reactive ion etching technology.

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