An electro-optical modulation device based on a micro electric heater and a manufacturing method thereof

Abstract

The present invention discloses an electro-optical modulation device based on a micro electric heater and a method for manufacturing the same. The device includes a substrate layer and a covering layer. The substrate layer is divided into two layers, the middle of the covering layer bulges upward, so that there is a space between the covering layer and the substrate layer. A number of gold nanodisks are arranged in the space, each of which is provided with a phase change material. The covering layer covers the phase change material, and metal electrodes are arranged on both sides of the covering layer. The electro-optical modulation device based on a micro electric heater of the present invention is composed of a silicon dioxide substrate, a gold nanodisk, a phase change material, a top covering layer and a metal electrode. The metal electrode serves as an electrode control unit of the device, and the covering layer serves as a light field control unit. By applying a voltage externally, the covering layer continuously generates Joule heat to drive the phase change material to undergo a phase change, so that its optical dielectric constant changes significantly, thereby realizing dynamic electro-optical modulation of mid-infrared band light.

Description

Technical Field

[0001] The present invention relates to the field of electro-optic modulation technology, and in particular to an electro-optic modulation device based on a micro electric heater and a manufacturing method thereof. Background Art

[0002] At present, in order to be compatible with semiconductor processing technology, the best way for traditional optical modulators to prepare integrated, large-area, high-density, low-energy-consumption dimmable devices is still the top-down stacking solution. However, the top-down stacking configuration requires the top electrode (covering layer) to be transparent, resistant to high temperatures, and stable in state. ITO (indium tin oxide) meets these requirements, but ITO has high transmittance in the visible and near-infrared bands (400nm-2um), but low transmittance in the mid-infrared band (2-10um). In addition, the phase change material has a filamentation phenomenon during the phase change process, that is, the initially crystallized thin wire becomes a current conduit with higher conductivity than the surrounding amorphous matrix. The current will pass through the phase change material along the optimal path to prevent uniform crystallization of the entire volume, hindering the dynamic switching of the phase change material between the crystalline and amorphous states.

[0003] A "spatial light-type electro-optical modulation device based on phase change material and its manufacturing method" disclosed in Chinese patent literature, with the announcement number CN113376870A, the device is composed of a multi-layer composite structure of a substrate, a lower electrode layer, a phase change layer, an upper electrode layer and a covering layer, wherein the upper and lower electrode layers respectively contain regularly arranged N-position and M-position metal micro-nano gratings, which serve as the device's electrodes and light field control units. By controlling the upper and lower electrode biases, the phase change material forms phase change regions with different degrees of crystallization, resulting in a significant change in the optical dielectric constant, thereby dynamically electro-modulating the reflected light and the resonant absorption peak of the device. Although the device of this invention has the advantages of being able to achieve nearly 100% perfect absorption, achieving a modulation depth of about 80% when transitioning between amorphous and crystalline states, and being able to dynamically control the amplitude of spatial incident light, it does not solve the problem of filamentation of phase change materials during the phase change process and low transmittance in the mid-infrared band. Summary of the invention

[0004] The present invention aims to overcome the problems of filamentation and low transmittance in the mid-infrared band in the phase change process of the phase change material in the prior art, and provides an electro-optic modulation device based on a micro electric heater and a manufacturing method thereof.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] An electro-optical modulation device based on a micro electric heater includes a substrate layer and a covering layer, wherein the substrate layer is divided into two layers, the upper layer material is silicon dioxide, and the lower layer material is silicon, the middle of the covering layer bulges upward, so that there is a space between the covering layer and the substrate layer, and a plurality of gold nanodisks are arranged in the space, each of which is provided with a phase change material, and the covering layer covers the phase change material, and metal electrodes are arranged on both sides of the covering layer. An electro-optical modulation device based on a micro electric heater of the present invention is composed of a multi-layer composite of a silicon dioxide substrate, a gold nanodisk, a phase change material, a covering layer on the top, and a metal electrode, wherein the metal electrode serves as an electrode control unit of the device, and the covering layer serves as a light field control unit, and by applying a voltage externally, the covering layer continuously generates Joule heat to drive the phase change material to undergo a phase change, so that its optical dielectric constant changes significantly, thereby realizing dynamic electro-optical modulation of mid-infrared band light.

[0007] As a preferred embodiment of the present invention, the material of the cover layer is a two-dimensional Dirac semimetal PtSe 2 , the thickness of the covering layer is 100-300nm, and the width is 30μm×30μm. The semi-metallic material PtSe2 has the characteristics of good stability, non-oxidation, hydrophobicity, good conductivity and high light transmittance. The mid-infrared transparent PtSe2 can enhance the interaction between spatial light and phase change materials and reduce light loss; at the same time, the covering layer is used for device protection, which can effectively prevent the oxidation and volatilization of the phase change material; the thickness of the covering layer in the present invention can be selected in a variety of ways, all of which can achieve the results of the present invention.

[0008] As a preferred embodiment of the present invention, the shape of the gold nanodisk is circular, the diameter of the gold nanodisk is 200-1000 nm, the thickness of the gold nanodisk is 100-150 nm, and the distance between the gold nanodisks is the same as the diameter of the gold nanodisk.

[0009] As a preferred embodiment of the present invention, the shape of the phase change material is the same as that of the gold nanodisk. 2 Sb 2 Te 5 , all phase change materials make up Ge 2 Sb 2 Te 5 Nanopillar array, the diameter of the phase change material is the same as the diameter of the gold nanodisk, and the thickness of the phase change material is 150-200nm. 2 Sb 2 Te 5 After the phase change, no energy is required to maintain the state, which has the advantage of non-volatility. The phase change material is stimulated by a voltage pulse. The Ge 2 Sb 2 Te 5Phase change materials have a short crystallization time, and the phase state after phase change can exist stably and can be converted between different phases. The phase change process has the advantages of being fast, stable and reversible. The present invention deposits the phase change material in a pre-prepared nanopore array to form a disk-like structure. By shrinking Ge 2 Sb 2 Te 5 The volume to surface area ratio reduces the effect of filamentation.

[0010] As a preferred embodiment of the present invention, the shape of the gold nanodisk can also be one of square, rectangle, cross and ring.

[0011] As a preferred embodiment of the present invention, the material of the metal electrode is one of gold, silver, platinum, tungsten, aluminum and copper. The metal electrode needs to have the characteristics of high conductivity, good stability and non-oxidation, and can maintain the long-term stability of the device.

[0012] As a preferred solution of the present invention, the thickness of the upper silicon dioxide layer of the substrate layer is 210nm, the thickness of the lower silicon layer of the substrate layer is 400um, the thickness of the metal electrode is 100nm, and the width is 1nm×1nm. The thickness of the phase change material of the intermediate phase change layer is 150-200nm. By optimizing the structural parameters of the metal electrode, the phase change material and the cover layer, the best modulation capability of the spatial light can be obtained.

[0013] A method for manufacturing an electro-optical modulation device based on a micro electric heater comprises the following steps: S1: using a coating machine to spin-coat PMMA on a substrate layer; S2: exposing a pattern by electron beam and developing it; S3: using electron beam evaporation to deposit gold nanodisks and phase change materials on the substrate, and removing the residual glue; S4: using a two-dimensional material transfer technology to transfer the cover layer to the device at a fixed point; S4 specifically comprises: applying a single crystal PtSe with a lateral size of 1 mm to the substrate; 2 PtSe layered by multiple tearing on tape 2 Then, several layers of PtSe were torn off from the tape using a 500 μm thick PDMS film. 2 , and attached to a glass slide, and at a temperature of 110°C, the volume expansion of PDMS was used to expand several layers of PtSe 2 The present invention relates to a method for manufacturing an electro-optical modulator based on a micro-electric heater, which is suitable for manufacturing an electro-optical modulator based on a micro-electric heater. The device comprises a silicon dioxide substrate, a gold nanodisk, a phase change material, a top PtSe 2 The multilayer composite structure consists of a covering layer and a metal electrode; PtSe 2 / Ge 2 Sb2 Te 5 / Au three-layer stacked structure electro-optic modulator, semi-metallic multilayer PtSe 2 With Ge 2 Sb 2 Te 5 The film forms a heterojunction; the incident light and Ge 2 Sb 2 Te 5 The interaction forms a local surface plasma resonance, and the magnetic field is confined in the intermediate phase change layer (phase change material), generating magnetic plasmon resonance to achieve light field regulation; applying current pulses at both ends of the top metal electrode can induce the intermediate Ge 2 Sb 2 Te 5 Phase transition of nanopillar arrays makes Ge 2 Sb 2 Te 5 The optical dielectric constant of the device changes significantly, thereby dynamically electromodulating the reflected light and resonant absorption peak of the device.

[0014] Therefore, the present invention has the following beneficial effects: the semi-metallic material PtSe selected for the cover layer in the device of the present invention 2 PtSe has the characteristics of good stability, non-oxidation, hydrophobicity, good conductivity and high light transmittance. 2 It can enhance the interaction between spatial light and phase change materials and reduce light loss; at the same time, the cover layer is used for device protection, which can effectively prevent the phase change material from oxidation and volatilization; the phase change material Ge of the present invention 2 Sb 2 Te 5 After the phase change, no energy is required to maintain the state, which has the advantage of non-volatility. The phase change material is stimulated by a voltage pulse. The Ge 2 Sb 2 Te 5 Phase change materials have a short crystallization time, and the phase state after phase change can exist stably and can be converted between different phases. The phase change process has the advantages of being fast, stable and reversible. The present invention deposits the phase change material in a pre-prepared nanopore array to form a disk-like structure. By shrinking Ge 2 Sb 2 Te 5 The ratio of volume to surface area reduces the influence of filamentation; the present invention optimizes the structural parameters of metal electrodes, phase change materials and covering layers to obtain the best modulation capability of spatial light. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a cross-sectional view of a structural unit of the electro-optical modulation device of the present invention.

[0016] Figure 2 It is a top view of the structural unit of the electro-optical modulation device of the present invention.

[0017] Figure 3 It is a far-field infrared test principle diagram of the electro-optical modulation device of the present invention.

[0018] Figure 4 This is a spectrum test chart of the electro-optical modulation device of the present invention.

[0019] Figure 5 This is a spectrum test result diagram of the electro-optical modulation device based on a micro electric heater simulated by the present invention.

[0020] Figure 6 The electro-optical modulation device of the present invention has a thickness of 217.6nm PtSe 2 Reflection spectrum in the mid-infrared wavelength range before power is applied.

[0021] Figure 7 The electro-optical modulation device of the present invention has a thickness of 217.6nm PtSe 2 Reflection spectrum in the mid-infrared wavelength range after power is applied.

[0022] Figure 8 It is a method flow chart of a method for manufacturing an electro-optical modulation device based on a micro electric heater of the present invention.

[0023] Fig. 9 It is a schematic diagram of a method flow of a method for manufacturing an electro-optical modulation device based on a micro electric heater of the present invention.

[0024] In the figure: 1. upper substrate layer; 2. lower substrate layer; 3. gold nanodisk; 4. phase change material; 5. metal electrode; 6. covering layer. DETAILED DESCRIPTION

[0025] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments.

[0026] like Figure 1 and Figure 2 As shown, an electro-optical modulation device based on a micro electric heater includes a substrate layer and a covering layer 6, wherein the substrate layer is divided into an upper and a lower layer, wherein the material of the upper layer 1 of the substrate layer is silicon dioxide, and the material of the lower layer 2 of the substrate layer is silicon, wherein the middle of the covering layer 6 is convex upward, so that there is a space between the covering layer 6 and the substrate layer, wherein a plurality of gold nanodisks 3 are arranged in the space, wherein each gold nanodisk 3 is provided with a phase change material 4, wherein the covering layer 6 covers the phase change material 4, and wherein metal electrodes 5 are arranged on both sides of the covering layer 6; wherein the material of the covering layer 6 is a two-dimensional Dirac semimetal PtSe 2, the thickness of the covering layer 6 is 100-300nm, and the length and width are 30μm×30μm; the shape of the gold nanodisk 3 is circular, the diameter of the gold nanodisk 3 is 200-1000nm, the thickness of the gold nanodisk 3 is 100-150nm, and the distance between the gold nanodisks 3 is the same as the diameter of the gold nanodisk 3; the shape of the phase change material 4 is the same as that of the gold nanodisk 3, and the phase change material 4 is Ge 2 Sb 2 Te 5 , all phase change materials 4 form Ge 2 Sb 2 Te 5 Nanocolumn array, the diameter of the phase change material 4 is the same as the diameter of the gold nanodisk 3, and the thickness of the phase change material 4 is 150-200nm; the shape of the gold nanodisk 3 can also be one of square, rectangle, cross and circular ring; the material of the metal electrode 5 is one of gold, silver, platinum, tungsten, aluminum, and copper; the thickness of the upper silicon dioxide of the substrate layer is 210nm, the thickness of the lower silicon layer of the substrate layer is 400μm, the thickness of the metal electrode 5 is 100nm, and the length and width are 1nm×1nm.

[0027] The present invention relates to a phase change material 4Ge 2 Sb 2 Te 5 Specifically, it involves a multilayer composite structure including a substrate layer, a gold nanodisk 3, a phase change layer, i.e., a phase change material 4, a cover layer 6, and a metal electrode 5, wherein the top PtSe 2 The cover layer 6 and the phase change layer are in close contact to form a micro heater; the phase change layer is induced to undergo phase change by generating Joule heat through an external power supply to achieve dynamic regulation of the multi-layer composite metasurface on spatial infrared incident light, causing the reflected light frequency to change; the present invention induces the intermediate Ge by applying a current pulse at both ends of the top metal electrode 5 2 Sb 2 Te 5 Phase transition of nanopillar arrays makes Ge 2 Sb 2 Te 5 The optical dielectric constant actively changes significantly, thereby achieving the regulation of spatial light and perfect absorption peak in the mid-infrared band.

[0028] like Figure 8 and Fig. 9As shown, a method for manufacturing an electro-optical modulation device based on a micro electric heater includes the following steps: S1: using a glue spreader to spin-coat PMMA on a substrate layer; PMMA is polymethyl methacrylate; S2: exposing a pattern by electron beam and developing; S3: using electron beam evaporation to deposit a gold nanodisk 3 and a phase change material 4 on the substrate, and removing the residual glue; S4: using a two-dimensional material transfer technology to transfer a cover layer 6 to the device at a fixed point; S4 specifically includes: applying a single crystal PtSe with a lateral size of 1 mm to the substrate; 2 PtSe layered by multiple tearing on tape 2 Then, several layers of PtSe were torn off from the tape using a 500 μm thick PDMS film. 2 , and attached to a glass slide, and at a temperature of 110°C, the volume expansion of PDMS was used to expand several layers of PtSe 2 Transfer to the upper silicon dioxide layer of the substrate layer; S5: Use the overlay technique to overlay a layer of metal electrode 5 on the cover layer 6, and then use the lift-off technique to obtain the electro-optical modulation device.

[0029] In this embodiment, a structural unit of an electro-optical modulation device based on a micro electric heater is provided. The device comprises a silicon dioxide substrate, a gold nanodisk 3, a phase change layer, i.e., a phase change material 4, and a top PtSe 2 The gold nanodisk 3 with a diameter of 200-1000 nm is grown on the silicon dioxide substrate by electron beam evaporation. The thickness of the gold nanodisk 3 is 100-150 nm. The thickness of the substrate Si is 400 μm. 2 The thickness is 210nm, the metal electrode 5 is 100nm thick, and the width and length are both 1mm, the thickness of the intermediate phase change layer is about 150nm, and the covering layer 6 is 100-300nm thick, and the width and length are both about 30μm; the top metal electrode 5 can be selected from any one of gold, silver, platinum, tungsten, aluminum and copper. In this embodiment, the precious metal material gold is selected, which has the characteristics of high conductivity, good stability and not easy to oxidize, and can maintain the long-term stability of the device; the covering layer 6 is a two-dimensional Dirac semimetal PtSe2; the two ends of the metal electrode 5 serve as the electrode control unit of the device, and the covering layer 6 serves as the light field control unit. By applying voltage externally, PtSe 2 With Ge 2 Sb 2 Te 5 The contact surface continuously generates Joule heat to drive the phase change material 4 to undergo a phase change, causing its optical dielectric constant to change significantly, thereby achieving dynamic electro-optical modulation of mid-infrared light. 2 It has the characteristics of good stability, non-oxidation, hydrophobicity, good conductivity (conductivity σ = 64000S / m) and high light transmittance, making it an ideal "window" material; mid-infrared transparent PtSe2 The interaction between spatial light and phase change material 4 can be enhanced to reduce light loss. At the same time, the cover layer 6 is used for device protection and can effectively prevent the phase change layer from being oxidized and volatilized. In the present invention, the thickness of the cover layer 6 can be selected in a variety of ways, all of which can achieve the results of the present invention. The phase change layer is made of Ge 2 Sb 2 Te 5 , specifically Ge 2 Sb 2 Te 5 Nanocolumn array, diameter and shape are consistent with gold nanodisk 3, thickness is 150-200nm; the phase change layer can be made of Ge 2 Sb 2 Te 5 ,Ge 3 Sb 2 Te 6 、GeTe、Sb 2 Te 3 The phase change layer must have at least two crystalline phases, and different phases can be converted into each other and can exist independently and stably to achieve active tuning of the optical dielectric constant; ensure that in the local area, that is, PtSe 2 With Ge 2 Sb 2 Te 5 The contact part can generate enough Joule heat to drive Ge 2 Sb 2 Te 5 Phase change occurs; the device can induce phase change of phase change material 4 through voltage pulse, and change the voltage by external excitation so that Ge 2 Sb 2 Te 5 The dielectric constant changes significantly, realizing dynamic regulation of spatial incident light; the shape of the gold nanodisk 3 on the substrate can have different design schemes, such as square, strip, cross and circular shapes, and different shape designs can achieve the results of the present invention.

[0030] Cover layer 6 is a semi-metal material PtSe 2 Semi-metallic materials have excellent infrared performance and zero band gap. They can simultaneously exhibit electrical properties between semiconductors and metals, while meeting the requirements of high conductivity and high transmittance in the mid-infrared band. Compared with ITO and indium tin oxide, ITO is highly transmittant in the visible and near-infrared bands (0.4-2um), but in the mid-infrared band (2-10um), ITO is no longer transparent, so the semi-metallic PtSe 2It is a suitable "window" material for the mid-infrared band, has the characteristics of high conductivity and high light transmittance, and can enhance the interaction between spatial light and the phase change layer; the device of the present invention can work in the mid-infrared band of 2-10μm; when the thickness of PtSe2 is 217.6nm, at a frequency of 2661.1cm -1 The maximum modulation depth is 64.8%, which indicates that the phase change of Ge2Sb2Te5 will cause the red shift of the resonance peak, which plays an important role in light modulation.

[0031] The electro-optical modulation device of the present invention is composed of a top metal electrode 5, a covering layer 6, a phase change layer, a gold nanodisk 3, and a substrate layer composite structure. In the mid-infrared band range of 2-10μm, the present invention has the ability of near-perfect absorption; the present invention can induce phase change in the phase change material 4 and cause significant changes in the optical dielectric constant through external voltage, and can realize dynamic regulation of spatial light; the device designed by the present invention has the advantages of non-volatility, simple manufacturing process and integration.

[0032] like Figure 1 As shown in the figure, it is a cross-sectional view of the structural unit of the electro-optical modulation device based on the micro electric heater. The cross-sectional structure is from bottom to top: substrate layer lower layer 2, substrate layer upper layer 1, gold nanodisk 3, phase change material 4, PtSe 2 Covering layer 6 and metal electrode 5. Spatial light is incident obliquely on the covering layer 6, forming an interaction between light and phase change material 4.

[0033] like Figure 1 As shown in the figure, as a typical up-and-down stacking structure, the two ends of the metal electrode 5 serve as the electrode control unit of the device, and the cover layer 6 serves as the light field control unit. 2 With Ge 2 Sb 2 Te 5 The contact surface continuously generates Joule heat to drive the phase change material 4 to undergo phase change, causing its optical dielectric constant to change significantly, thereby achieving dynamic modulation of infrared light in space.

[0034] like Figure 2 As shown in FIG. 1 , a top view of a structural unit of an electro-optical modulation device based on a micro electric heater is shown, wherein a metal electrode 5 is obtained by electron beam exposure, development, and electron beam evaporation coating, and is pressed on a PtSe 2 Above the cover layer 6. After continuous size optimization, the metal electrode 5 finally selected has a thickness of 100nm, a length and a width of 1mm×1mm. At this time, the electrode has the characteristics of low energy consumption and high heating efficiency, which can further reduce the size of the device.

[0035] like Figure 2 The figure shows a top view of the structural unit of the electro-optical modulation device based on a micro electric heater, in which PtSe2 The two-dimensional material transfer technology is used to transfer the PtSe to the corresponding position. Scotch tape is used to mechanically peel off the PtSe 2 The mechanical stress generated by the tape will offset the interlayer van der Waals force. 2 PtSe layered by multiple tearing on tape 2 , and then use the 500μm thick PDMS film to tear off the multi-layer or few-layer PtSe from the tape 2 At a heating temperature of 110°C, the volume expansion of PDMS was used to form a multi-layer or a few-layer PtSe 2 Slowly transfer to a silicon dioxide substrate.

[0036] like Figure 3 The figure shows the far-field test principle of the electro-optical modulation device based on the micro electric heater. The test results are mainly based on the spatial incident light and Ge 2 Sb 2 Te 5 The interaction forms a local surface plasmon resonance, and the magnetic field is confined in the intermediate phase change layer, generating magnetic plasmon resonance. Figure 6 The resonance peak and Ge 2 Sb 2 Te 5 When the electro-optic modulator is in the initial state, within a specific frequency range, the amplitude of the reflection peak can be close to 1, which has the characteristic of total reflection. 2 Sb 2 Te 5 After the film is transformed from amorphous to crystalline, the resonance peak will be significantly red-shifted. 2 Sb 2 Te 5 The increase in refractive index and extinction coefficient improves the structural light absorption capacity, and the resonance intensity shows a decrease to varying degrees.

[0037] like Figure 4 The figure shows the spectrum test simulation structure of the electro-optical modulation device based on the micro electric heater, which is composed of a silicon dioxide substrate, a gold film, and Ge 2 Sb 2 Te 5 Phase change layer, PtSe 2 The multilayer composite structure of the cover layer 6 and the metal electrode 5. In the simulation calculation, the thickness of the selected silicon dioxide substrate is 300nm, the thickness of the gold film is 100nm, and the Ge 2 Sb 2 Te 5 The thickness of the phase change layer is 150nm, PtSe 2The thickness of the cover layer 6 is 150 nm, and the thickness of the metal electrode 5 is 100 nm.

[0038] like Figure 5 As shown, the Ge 2 Sb 2 Te 5 Reflection spectra before and after phase transition. From the simulation results, it can be seen that amorphous Ge 2 Sb 2 Te 5 At 2523.7cm -1 The maximum absorption peak is reached at 2191.8cm -1 The maximum absorption peak is reached at Δω~331.9cm -1 At 2523.7cm -1 A modulation depth of 74.2% was achieved.

[0039] like Figure 6 The figure shows the electro-optical modulation device in the amorphous state. 2 The reflection spectrum in the mid-infrared wavelength range before power is applied, such as Figure 7 The figure shows the PtSe when the electro-optic modulation device is in the crystalline state. 2 Reflection spectrum in the mid-infrared wavelength range after power is applied. The optimal impedance matching is achieved after optimizing the structural dimensions, which enhances the Joule heat generated by powering on the device. 2 Sb 2 Te 5 The phase change occurs, thereby effectively changing its dielectric constant, so that it can achieve active tuning of the resonant wavelength redshift or blueshift. In the wavelength range of 2-10μm, when the phase change material 4 is in an amorphous state, the extinction coefficient k≈0, which is equivalent to the medium transmittance≈0, and the formula for the absorptivity can be simplified to A(ω)≈1-R(ω). Where A is the absorbance, R is the reflectivity, and ω is the frequency. The selected PtSe 2 The thickness is 217.6nm and the frequency is 2661.1cm -1 The maximum modulation depth is 64.8%. 2 Sb 2 Te 5 After the amorphous state is converted to the crystalline state, the first resonance peak of the reflectance spectrum measurement value changes from the frequency of 1332.5cm -1 Redshifted to a frequency of 991.17 cm -1 Δω~341.33cm -1 ; The second resonance peak is at a frequency of 2229.2cm -1 Redshifted to a frequency of 1895.6 cm -1Δω~333.6cm -1 ; The third resonance peak is at a frequency of 3370.8cm -1 Redshifted to a frequency of 2636.1 cm -1 Δω~734.7cm -1 From the shift of the absorption peak, it can be seen that the effective dielectric constant changes greatly before and after the phase change, the resonance wavelength shifts significantly, and the absorption spectrum undergoes a significant red shift.

[0040] The present invention discloses an electro-optical modulation device based on a micro electric heater and a manufacturing method thereof. The device comprises a silicon dioxide substrate, a gold nanodisk 3, a phase change layer, a top PtSe 2 The PtSe 2 / Ge 2 Sb 2 Te 5 / Au three-layer stacked structure electro-optic modulator, semi-metallic multilayer PtSe 2 With Ge 2 Sb 2 Te 5 The film forms a heterojunction. The incident light and Ge 2 Sb 2 Te 5 The interaction forms a local surface plasma resonance, and the magnetic field is confined in the intermediate phase change layer, generating magnetic plasmon resonance to achieve light field control. By applying a current pulse at both ends of the top gold electrode, the intermediate Ge 2 Sb 2 Te 5 Phase transition of nanopillar arrays makes Ge 2 Sb 2 Te 5 The optical dielectric constant of the device changes significantly, thereby dynamically electromodulating the reflected light and the resonance absorption peak of the device. The device involved in the present invention can work in the mid-infrared (MIR) band of 2-10μm. 2 When the thickness is 217.6nm, the frequency is 2661.1cm -1 At , the maximum modulation depth is 64.8%. This indicates that Ge 2 Sb 2 Te 5 The phase change will cause the red shift of the resonance peak, which plays an important role in light modulation.

[0041] The core idea of ​​the present invention is: in view of the structural modeling of traditional optical modulators and the problems existing in the phase change of new electro-optical materials - phase change material 4, an electro-optical modulation device based on a micro-electric heater is proposed to solve the problems of opaque top electrode materials, large light loss and filamentation phenomenon in the phase change of phase change material 4 of traditional electro-optical modulators. Referring to the mature process flow, in order to be compatible with semiconductor processing technology, the best way to prepare integrated, large-area, high-density, low-energy consumption adjustable light devices is still the up and down stacking solution. However, the up and down stacking configuration requires that the top electrode must be transparent, resistant to high temperatures, and environmentally stable. ITO and indium tin oxide meet these requirements. ITO has high transmittance in the visible light and near-infrared bands (400nm-2um), but low transmittance in the mid-infrared band (2-10um). Semi-metallic material PtSe 2 It has the characteristics of good stability, non-oxidation, hydrophobicity, good conductivity (conductivity σ = 64000S / m) and high light transmittance (MIR). 2 Due to its high transmittance in the mid-infrared band and good conductivity, the present invention uses the two-dimensional Dirac semimetal PtSe 2 As the cover layer 6, the mid-infrared light is modulated as a modulation unit of the electric field and the optical field.

[0042] In addition, there is a filamentation phenomenon during the phase change process of the phase change material 4, that is, the initially crystallized thin wire becomes a current conduit with higher conductivity than the surrounding amorphous matrix, and the current will pass through the phase change material 4 along the optimal path to prevent uniform crystallization of the entire volume. Filamentation will hinder the dynamic switching of the phase change material 4 between the crystalline and amorphous states. Therefore, another key to the present invention is how to set the structure and size of the device to avoid the filamentation phenomenon. In the present invention, the phase change material 4 is deposited in a nanopore array prepared in advance, and the influence of the filamentation phenomenon is reduced by reducing the ratio of the volume and surface area of ​​the phase change material 4.

[0043] On the other hand, in order to solve the problem of increased optical loss caused by the cover layer 6, the present invention proposes to use a thinner cover layer 6 to achieve better overlap of the optical field and the electric field without increasing the optical loss. The optimal thickness of the cover layer 6 is determined by comprehensively considering the minimum thickness of the cover layer 6 and the electro-optical overlap factor under the premise of fixed additional optical loss.

[0044] The specific embodiments described herein are merely examples of the spirit of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in similar ways, but they will not deviate from the spirit of the present invention or exceed the scope defined by the appended claims.

[0045] Although the terms such as phase change layer, cover layer, electron beam exposure and two-dimensional material transfer are used more frequently in this article, the possibility of using other terms is not excluded. These terms are used only to more conveniently describe and explain the essence of the present invention, and interpreting them as any additional limitation is contrary to the spirit of the present invention.

[0046] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto, and any changes or substitutions that are not conceived through creative work should be included in the protection scope of the present invention.

Claims

1. An electro-optical modulation device based on a micro electric heater, Its characteristics are: It includes a substrate layer and a covering layer. The substrate layer is divided into an upper and lower layer. The upper layer material is silicon dioxide, and the lower layer material is silicon. The middle of the covering layer bulges upward so that there is a space between the covering layer and the substrate layer. Several gold nanodisks are arranged in the space, each of which is provided with a phase change material. The covering layer covers the phase change material, and metal electrodes are arranged on both sides of the covering layer.

2. An electro-optical modulation device based on a micro electric heater according to claim 1, Its characteristics are: The material of the covering layer is a two-dimensional Dirac semimetal PtSe 2 The covering layer has a thickness of 100-300 nm and a width of 30 μm×30 μm.

3. The electro-optical modulation device based on a micro electric heater according to claim 1, Its characteristics are: The shape of the gold nanodisk is circular, the diameter of the gold nanodisk is 200-1000 nm, the thickness of the gold nanodisk is 100-150 nm, and the distance between the gold nanodisks is the same as the diameter of the gold nanodisk.

4. The electro-optical modulation device based on a micro electric heater according to claim 1, Its characteristics are: The shape of the phase change material is the same as that of the gold nanodisk. The phase change material is Ge 2 Sb 2 Te 5 , all phase change materials make up Ge 2 Sb 2 Te 5 Nanopillar array, the diameter of the phase change material is the same as the diameter of the gold nanodisk, and the thickness of the phase change material is 150-200nm.

5. An electro-optical modulation device based on a micro electric heater according to claim 1 or 4, Its characteristics are: The shape of the gold nanodisk can also be one of square, rectangle, cross and ring.

6. The electro-optical modulation device based on a micro electric heater according to claim 5, Its characteristics are: The material of the metal electrode is one of gold, silver, platinum, tungsten, aluminum and copper.

7. The electro-optical modulation device based on a micro electric heater according to claim 1, Its characteristics are: The thickness of the upper silicon dioxide layer of the substrate layer is 210 nm, the thickness of the lower silicon layer of the substrate layer is 400 μm, the thickness of the metal electrode is 100 nm, and the width is 1 nm×1 nm.

8. A method for manufacturing an electro-optical modulation device based on a micro electric heater according to claim 1, Its characteristics are: The following steps are involved: S1: Spin-coat PMMA on the substrate layer using a coating machine; S2: Expose the pattern by electron beam and develop; S3: Depositing gold nanodisks and phase change materials on the substrate using electron beam evaporation and removing the residual glue; S4: Use 2D material transfer technology to transfer the cover layer to the device; S5: A layer of metal electrode is overlaid on the cover layer using overlay technology, and then an electro-optical modulation device is obtained using a lift-off technology.

9. The method for manufacturing an electro-optical modulation device based on a micro electric heater according to claim 8, Its characteristics are: The S4 is specifically as follows: a single crystal PtSe with a lateral size of 1 mm is placed 2 PtSe layered by multiple tearing on tape 2 Then, several layers of PtSe were torn off from the tape using a 500 μm thick PDMS film. 2 , and attached to a glass slide, and at a temperature of 110°C, the volume expansion of PDMS was used to expand several layers of PtSe 2 Transfer to the upper silicon dioxide layer of the substrate layer.

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