A method for dynamic tuning control of metamaterials based on IGZO Schottky diodes

Abstract

The present invention relates to a method for dynamically adjusting and controlling a metamaterial based on an IGZO Schottky diode. The IGZO Schottky diode includes a substrate, a Schottky electrode, an amorphous indium gallium zinc oxide (AGIZO) active layer, and an ohmic electrode, grown sequentially from bottom to top. The method involves the following steps: (1) using a metamaterial as the Schottky electrode, allowing the amorphous Indium Gallium Zinc Oxide (AGIZO) active layer to completely cover the metamaterial's capacitive structure, which then couples with the AGIZO active layer to form a Schottky barrier; (2) dynamically adjusting and controlling the metamaterial via the IGZO Schottky diode processed in step (1). The method achieves large dynamic modulation of the metamaterial's electromagnetic properties, including transmittance, reflectance, and absorption, without affecting the resonant frequency of the metamaterial structure design. This method is applicable to various metamaterial devices and plasmonic devices with metamaterial structures, enabling dynamic tuning of both space-transmitted and surface-transmitted electromagnetic waves.

Description

[Technical field]

[0001] The present invention relates to a method for dynamic tuning control of metamaterials based on IGZO Schottky diodes, which belongs to the fields of semiconductor device technology, electromagnetic field and microwave technology, etc. [Background technology]

[0002] Metamaterials, also known as "supermaterials", "unnatural materials" or "extraordinary materials", refer to artificial composite structures or materials with extraordinary physical properties not found in natural materials. Metamaterials are generally composed of artificially designed metallic or dielectric microstructures with uniform periodic distribution and subwavelength size, and achieve specific electromagnetic responses through the coupling between these microstructures and incident electromagnetic waves. In recent years, metamaterials whose electromagnetic properties can be artificially designed have well filled the gap of traditional materials, and by combining these metamaterials with tunable and controllable material systems such as semiconductors, liquid crystals, and superconductors, active tuning and control over the electromagnetic properties of metamaterials can be realized by external excitations such as light, applied electric field, applied magnetic field, stress, or chemical reagents.

[0003] Among these methods of active tuning control of metamaterials, the most commonly used is to use a field effect transistor (triode) structure to tune the carrier density of the material. For example, for tuning control of the oxide semiconductor IGZO, see Xu, WZ et al. Electrically tunable terahertz metamaterials with embedded large-area transparent thin-film transistor arrays. Sci. Rep. 6, 23486(2016). For tuning and controlling graphene, see Ju, L. et al. Graphene plasmonics for tunable terahertz metamaterials. Nat Nanotechnol. 6, 630-634(2011); Jadidi, MM et al. Tunable Terahertz Hybrid Metal-Graphene Plasmons. Nano Lett. 15, 7099-7104 (2015); and Balci, O. et al. Graphene-enabled electrically switchable radar-absorbing surfaces. Nat. Commun. 6, 6628(2015). So far, most active metamaterial tuning control is based on graphene transistors, whose tuning depth is limited by the quality of the graphene, see Geim, AK & Novoselov, KS The rise of graphene, Nat. Mater. 6, 183-191(2007), metamaterials based on IGZO field effect transistors have a very low tuning depth, and the transistor gate has a negative effect on the electromagnetic properties of the metamaterial.

[0004] In addition, Schottky diodes can dynamically tune metamaterials by tuning the carrier concentration of the semiconductor channel. In 2006, active tuning of metamaterials at terahertz frequencies using gallium arsenide (GaAs) Schottky diodes was reported, see Chen, H.-T. et al. Active terahertz metamaterial devices. Nature 444, 597-600(2006) and Chen, H.-T. et al. A metamaterial solid-state terahertz phase modulator. Nature Photonics 3, 148-151(2009). However, currently, no other Schottky diodes can achieve dynamic tuning of metamaterials. The GaAs substrates used in the solutions reported in the above articles are rigid and expensive, and are not suitable for large-area or flexible circuits, nor for cost-effective metamaterial dynamic tuning applications. Summary of the Invention [Problem to be solved by the invention]

[0005] In view of the shortcomings of the prior art, the present invention provides a method for dynamic tuning control of metamaterials based on IGZO Schottky diodes.

[0006] The present invention is the first to use IGZO Schottky diodes to realize dynamic tuning control of metamaterials. The present invention overcomes the problems of low modulation depth, high cost, complex manufacturing process, and unsuitability for flexible circuits in multiple types of solutions for traditional metamaterial active tuning control by using IGZO Schottky diodes with high electron mobility (10-50 cm). 2IGZO, which has low EMI (electrochemical loss), low cost, simple growth and fabrication process, and good uniformity, is used as the active layer to fabricate a metal metamaterial, while fabricating Schottky and ohmic electrodes to form a Schottky diode, and active tuning control of the electromagnetic properties of the metamaterial is realized by applying voltage to the ohmic and Schottky electrodes. Compared with semiconductors with narrow bandwidth or no energy gap, such as gallium arsenide and graphene, IGZO has a wide energy band and excellent stability, so the dynamic tuning control of the IGZO Schottky diode can function in visible light and a wide temperature range. IGZO Schottky diodes can be fabricated by magnetic co-sputtering at room temperature, which has the advantages of large area, high yield, low cost, and can be used in flexible circuits.

[0007] Explanation of terms: 1. DECON refers to decon cleaning agent. 2. IGZO is indium gallium zinc oxide, an oxide semiconductor, and is the active layer of Schottky diodes. 3. Capacitive metamaterials refer to metamaterials that have an equivalent capacitance in the circuit model, including split-ring metamaterials, capacitive inductive resonant metamaterials, and their various variants and composite metamaterials. 4. A surface plasmon transmission line is a new type of ultrafine transmission line that is fabricated on a dielectric substrate, has a subwavelength wrinkled structure, and has deep subwavelength electric field localization and is capable of resonant transmission. By forming an equivalent negative dielectric constant through the subwavelength structure, it realizes surface plasmon-like characteristics in the microwave and terahertz frequency bands. 5. Split ring metamaterial, the English name split ring resonator, refers to a metal ring structure with a gap, the metal wire can be regarded as inductance, the gap generates capacitance, and in a changing magnetic field, electric charges will accumulate on both ends of the gap, forming resonance. 6. Capacitive inductive resonant metamaterials, English name electric-LC metamaterials, the equivalent circuit model is an LC resonant circuit, the metal line can be regarded as inductance, and the gap can be regarded as capacitance, forming resonance. 7. The quasi-ring structure refers to a metal ring structure that shorts the gap of the split resonant ring. 8. Bandstop response refers to a response in which the signal strength is significantly attenuated in a specific spectral range and there is no signal attenuation outside the specific spectral range. [Means for solving the problem]

[0008] The technical solutions of the present invention are as follows:

[0009] A method for dynamic tuning control of a metamaterial based on an IGZO Schottky diode, the IGZO Schottky diode including a substrate, a Schottky electrode, an amorphous indium gallium zinc oxide active layer, and an ohmic electrode, which are sequentially grown from bottom to top, the method including the steps of: (1) using a metamaterial as the Schottky electrode, making the amorphous indium gallium zinc oxide active layer completely cover the capacitive structure of the metamaterial, and the capacitive structure of the metamaterial combines with the amorphous indium gallium zinc oxide active layer to form a Schottky barrier; Since the two metal plates of the metamaterial's capacitive structure share a common electric potential, a Schottky barrier is formed at the surfaces of the two metal plates, making the metamaterial operate as it does in its normal mode of operation. The IGZO material covers the capacitive structure of the metamaterial, and the operation mechanism of the capacitive structure of the metamaterial can be understood as an RLC circuit. Here, L represents the inductance of the ring structure, C represents the capacitance in the gap, and Rg represents the variable attenuation due to free carrier absorption in the gap. In the method of the present invention, the contact between the IGZO material and the capacitive structure of the metamaterial needs to cover the gap to fill the capacitive structure of the metamaterial. After applying a forward bias voltage, the carriers of the IGZO move in the direction of the positive voltage, that is, from the ohmic electrode to the Schottky electrode, and the free carrier concentration of the IGZO material in the gap of the capacitive structure of the metamaterial increases, and the conductivity at the Schottky electrode also increases accordingly. In this way, the gap of the capacitive structure of the metamaterial is short-circuited, and the reconstruction and dynamic tuning of the material is realized. (2) Dynamically tune and control the metamaterial via the IGZO Schottky diode processed in step (1).

[0010] According to the invention, preferably the gap of the capacitive structure of said metamaterial is smaller than 5 μm.

[0011] To ensure that the IGZO in the gaps of the capacitive structure of the metamaterial is in an exhausted state under the condition of zero bias voltage, the size of the capacitive structure of the metamaterial, i.e., the gaps covered by IGZO, should not exceed 5 μm.

[0012] According to the present invention, preferably, the material of the metamaterial includes Ti / Au / Pd.

[0013] Ti is used to act as an adhesion layer and improve the bonding strength between the metal and the substrate. Metal Au has good electrical conductivity as the main signal transmission layer, and as the thickness of Au increases, the loss of the transmission signal also decreases accordingly across the entire frequency band. High work function metal Pd forms an oxygen-rich environment after being bombarded by oxygen plasma, and forms a Schottky barrier after bonding with the amorphous indium gallium zinc oxide active layer. The metamaterial can be used with high work function metal Pd as the Schottky electrode, but is not limited to it, and any other metal that can form a Schottky barrier with IGZO can be used.

[0014] According to the present invention, preferably, the metamaterial includes a split ring metamaterial, a capacitively inductively resonant metamaterial, a split ring metamaterial array, or a capacitively inductively resonant metamaterial array.

[0015] According to the present invention, preferably, in the step (2), the metamaterial is dynamically adjusted and controlled via the IGZO Schottky diode processed in the step (1), and the step includes the following steps: A, A positive voltage is applied to the Schottky electrode and a negative voltage is applied to the Ohmic electrode. B, Under zero bias condition, the IGZO in the amorphous indium gallium zinc oxide active layer covering the gap of the metamaterial capacitive structure is exhausted, and the metamaterial capacitive structure forms a strong LC resonance, resulting in a complete bandstop response, and produces a strong bandstop response down to -31 dB for 49 GHz electromagnetic waves. C. Continuously increase the voltage from zero to positive. With the increase of the positive voltage, the carriers in the IGZO of the amorphous indium gallium zinc oxide active layer move in the direction of the positive voltage, that is, from the ohmic electrode to the Schottky electrode, and the IGZO free carrier concentration of the amorphous indium gallium zinc oxide active layer in the gap of the capacitive structure of the metamaterial gradually increases, and the conductivity increases, so that the capacitance of the gap decreases until it is short-circuited, and the metamaterial structure gradually becomes a quasi-ring structure, which has a weaker attenuation response to electromagnetic signals and produces a higher transmittance.

[0016] According to the present invention, preferably, a method for fabricating an IGZO Schottky diode for dynamic tuning control of the metamaterial produced in step (1) comprises the steps of: (1) cleaning a substrate; (2) depositing the metamaterial on the substrate as a Schottky electrode in (1) using photolithography, electron beam evaporation, and lift-off techniques; Step (3) of fabricating an amorphous indium gallium zinc oxide active layer on the Schottky electrode of step (2); By photolithography, electron beam evaporation and lift-off techniques, an ohmic electrode is fabricated on the amorphous indium gallium zinc oxide active layer in step (3). The material is Ti / Au, and the thickness is 10 / 300 nm in step (4).

[0017] More preferably, step (1) includes first rinsing with DECON for 5 minutes, then with deionized water for 10 minutes, then with acetone for 5 minutes, immediately with ethanol for 5 minutes, then with deionized water, and finally with nitrogen for blowing dry.

[0018] More preferably, the step (3) includes transferring a pattern of the amorphous indium gallium zinc oxide active layer onto the sample of step (2) by photolithography, putting the sample into a plasma cleaner and cleaning it with oxygen plasma for 30 minutes to remove any remaining adhesive on the surface and create an oxygen-rich environment on the surface, and fabricating a 750 nm-thick amorphous indium gallium zinc oxide active layer by photolithography, magnetron sputtering and lift-off techniques. Effect of the Invention

[0019] The beneficial effects of the present invention are as follows:

[0020] In the present invention, the combination of IGZO Schottky diode structure and metamaterial is used to realize large dynamic modulation of the electromagnetic properties of metamaterials, such as transmittance, reflectance, and absorptance, while at the same time not affecting the resonant frequency of the metamaterial structure design. This can be applied to various metamaterial devices and plasmon devices with metamaterial structures to realize dynamic adjustment control of spatial transmission type electromagnetic waves and surface transmission type electromagnetic waves. [Brief description of the drawings]

[0021] [Figure 1] Figure 1(a) is a schematic diagram of Structure 1 of an IGZO Schottky diode with a single-ring split-ring metamaterial as the Schottky electrode, and (b) is a schematic diagram of Structure 2 of an IGZO Schottky diode with a single-ring split-ring metamaterial as the Schottky electrode. [Diagram 2] FIG. 2(a) is a schematic diagram of Structure 1 of an IGZO Schottky diode with a capacitive inductive resonant metamaterial as the Schottky electrode, and (b) is a schematic diagram of Structure 1 of an IGZO Schottky diode with a capacitive inductive resonant metamaterial as the Schottky electrode. [Diagram 3] Figure 3 is a schematic diagram of the structure of an IGZO Schottky diode with a split-ring metamaterial array as the Schottky electrode. [Figure 4] Figure 4 is a schematic diagram of the structure of an IGZO Schottky diode with a capacitively inductively resonant metamaterial array as the Schottky electrode. [Diagram 5] Figure 5 is a schematic diagram of the structure of an IGZO Schottky diode space with a split-ring metamaterial as the Schottky electrode. [Figure 6] Figure 6 is a schematic diagram of the structure of an IGZO Schottky diode space with a capacitive inductively resonant metamaterial as the Schottky electrode. [Figure 7] FIG. 7 is a schematic diagram of the operating principle of a metamaterial capacitive structure. [Figure 8] FIG. 8 is a schematic diagram of dynamic adjustment control of the transmission of electromagnetic waves (artificial surface plasmons) using the present invention. [Figure 9] FIG. 9 is a schematic diagram of dynamic adjustment control of the absorption of electromagnetic waves (artificial surface plasmons) using the present invention. [Figure 10] FIG. 10 is a schematic diagram comparing the signal transmittance of a metamaterial with a covered IGZO Schottky diode and a metamaterial with an uncovered IGZO Schottky diode when no voltage is applied. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] The present invention will now be further defined, but not limited, by reference to the following specification figures and examples.

[0023] Example 1 A method for dynamic tuning control of a metamaterial based on an IGZO Schottky diode, the IGZO Schottky diode including a substrate, a Schottky electrode, an amorphous indium gallium zinc oxide active layer, and an ohmic electrode, which are sequentially grown from bottom to top, the steps of which include: (1) using a metamaterial as the Schottky electrode, making the amorphous indium gallium zinc oxide active layer completely cover the capacitive structure of the metamaterial, and the capacitive structure of the metamaterial combines with the amorphous indium gallium zinc oxide active layer to form a Schottky barrier; Because the two metal plates in the metamaterial's capacitive structure share a common electric potential, a Schottky barrier is formed on the surfaces of the two metal plates, making the metamaterial operate as it does in its normal mode of operation. The IGZO material covers the capacitive structure of the metamaterial, and the operation mechanism of the capacitive structure of the metamaterial can be understood as an RLC circuit shown in Figure 7, where L is the inductance of the ring structure, C is the capacitance in the gap, and Rg is the variable attenuation due to free carrier absorption in the gap. In the method of the present invention, the contact between the IGZO material and the capacitive structure of the metamaterial needs to cover the gap to fill the capacitive structure of the metamaterial. After applying a forward bias voltage, the carriers of the IGZO move in the direction of the positive voltage, that is, from the ohmic electrode to the Schottky electrode, and the free carrier concentration of the IGZO material in the gap of the capacitive structure of the metamaterial increases, and the conductivity at the Schottky electrode also increases accordingly. In this way, the gap of the capacitive structure of the metamaterial is short-circuited, and the reconstruction and dynamic tuning of the material is realized. (2) The metamaterial was dynamically tuned via the IGZO Schottky diode processed in step (1).

[0024] Example 2 The dynamic tuning control method of the metamaterial based on IGZO Schottky diode according to the embodiment 1, the distinction being that the gap of the capacitive structure of the metamaterial is smaller than 5 μm.

[0025] To ensure that the IGZO in the gaps of the capacitive structure of the metamaterial is in an exhausted state under the condition of zero bias voltage, the size of the capacitive structure of the metamaterial, i.e., the gaps covered by IGZO, should not exceed 5 μm.

[0026] Example 3 The dynamic tuning control method of the metamaterial based on the IGZO Schottky diode according to the first embodiment, the distinction of which is as follows: The materials of the metamaterial include Ti / Au / Pd. Ti acts as an adhesive layer and is used to improve the bonding strength between the metal and the substrate. Metal Au has good electrical conductivity as the main signal transmission layer, and as the thickness of Au increases, the loss of the transmission signal also decreases accordingly across the entire frequency band. After being bombarded by oxygen plasma, high work function metal Pd formed an oxygen-rich environment and formed a Schottky barrier after bonding with the amorphous indium gallium zinc oxide active layer. The metamaterial can be used but is not limited to high work function metal Pd as the Schottky electrode, and all other metals that can form a Schottky barrier with IGZO can be used.

[0027] The metamaterial includes a split ring metamaterial, a capacitive inductive resonant metamaterial, a split ring metamaterial array, or a capacitive inductive resonant metamaterial array. As shown in FIG. 1(a), FIG. 1(a) is a structure 1 of an IGZO Schottky diode with a single ring split ring metamaterial as a Schottky electrode, FIG. 1(b) is a structure 2 of an IGZO Schottky diode with a single ring split ring metamaterial as a Schottky electrode, FIG. 2(a) is a structure 1 of an IGZO Schottky diode with a capacitive inductive resonant metamaterial as a Schottky electrode, FIG. 2(b) is a structure 2 of an IGZO Schottky diode with a capacitive inductive resonant metamaterial as a Schottky electrode, FIG. 3 and FIG. 5 are respectively shown, and FIG. 4 and FIG. 6 are respectively shown. Other types of split-ring metamaterials and capacitive inductive resonant metamaterials can also be combined with IGZO Schottky diodes to achieve dynamic control, and the combination methods are similar to those shown in Figures 1 to 6.

[0028] Example 4 The dynamic tuning control method of the metamaterial based on the IGZO Schottky diode according to the first embodiment, in which the distinction is as follows: Dynamically tuning and controlling the metamaterial via the IGZO Schottky diode processed in step (1) includes the following steps. A, A positive voltage was applied to the Schottky electrode and a negative voltage was applied to the ohmic electrode. B, In the zero bias state, the IGZO in the amorphous indium gallium zinc oxide active layer, which covers the gap of the capacitive structure of the metamaterial, is exhausted, and the capacitive structure of the metamaterial forms a strong LC resonance, resulting in a complete band-stop response, and produces a strong band-stop response down to -31 dB for 49 GHz electromagnetic waves, as shown in Figures 6-8. C. The voltage is continuously increased from zero to positive. With the increase of the positive voltage, the carriers in the IGZO of the amorphous indium gallium zinc oxide active layer move in the direction of the positive voltage, that is, from the Ohmic electrode to the Schottky electrode, and the free carrier concentration of the IGZO of the amorphous indium gallium zinc oxide active layer in the gap of the capacitive structure of the metamaterial gradually increases, and the conductivity increases, so that the capacitance of the gap decreases until it is short-circuited, and the metamaterial structure gradually becomes a quasi-ring structure, which has a weaker attenuation response to electromagnetic signals and produces a higher transmittance. The material of the Schottky electrode is Pd, the thickness of the Schottky electrode is greater than 10 nm, the thickness of the amorphous indium gallium zinc oxide active layer is greater than 10 nm, and the ohmic electrode is Ti or Au, the thickness of which is greater than 10 nm.

[0029] The fabrication method of the IGZO Schottky diode for dynamic tuning control of the above metamaterial includes the following steps. (1) Cleaning of the substrate: first, wash with DECON for 5 minutes, then with deionized water for 10 minutes, then with acetone for 5 minutes, immediately with ethanol for 5 minutes, then rinse with deionized water, and finally blow dry with nitrogen. (2) Using photolithography, electron beam evaporation, and lift-off techniques, the metamaterial on the substrate in step (1) was deposited as a Schottky electrode. (3) An amorphous indium gallium zinc oxide active layer was fabricated on the Schottky electrode in step (2). The pattern of the amorphous indium gallium zinc oxide active layer was transferred to the sample in step (2) by photolithography, the sample was put into a plasma cleaner and cleaned with oxygen plasma for 30 minutes to remove the adhesive remaining on the surface and create an oxygen-rich environment on the surface, and an amorphous indium gallium zinc oxide active layer with a thickness of 750 nm was fabricated by photolithography, magnetron sputtering, and lift-off techniques. (4) By photolithography, electron beam evaporation and lift-off techniques, an ohmic electrode was fabricated on the amorphous indium gallium zinc oxide active layer in step (3). The material is Ti / Au, and the thickness is 10 / 300 nm.

[0030] FIG. 8 is a schematic diagram of dynamic adjustment control of the transmission of electromagnetic waves (artificial surface plasmons) using the present invention.

[0031] Limited by the protection voltage of the high frequency test equipment, the upper limit of the test voltage is 46V. In order to obtain an ideal modulation range, the HFSS simulation software of Ansys was used to simulate the tuning effect of the IGZO Schottky diode on the metamaterial. From the DC test results of the split resonant ring, the variable conductivity value was extracted, and with the increase of the applied bias voltage, the conductivity of the IGZO material increased, and the actual variation range of the conductivity of the IGZO material was 7.9 × 10 -6 ~0.23 Sm. By adjusting the conductivity of the IGZO material in the simulation to 0.016 Sm, the ideal modulation range of the transmittance can be further increased to 67% and the ideal modulation range of the absorptance can be further increased to 32%. When the forward bias voltage is applied to 46 V, it can be seen that the transmittance of the signal can be modulated from -30 dB to -7 dB, and at the same time, there is no shift in the resonant frequency due to this modulation.

[0032] Fig. 9 is a schematic diagram of the dynamic adjustment control of the absorption of electromagnetic waves (artificial surface plasmons) using the present invention. As shown in Fig. 9, with the increase of the bias voltage, when a positive voltage of 46V is applied, the modulation range of the absorption rate of the metamaterial structure can reach 19%.

[0033] Figure 10 is a schematic diagram comparing the signal transmittance of the metamaterial with and without the IGZO Schottky diode covered when no voltage is applied. From Figure 10, it can be seen that the cover of the IGZO Schottky diode has little effect on the electromagnetic properties of the metamaterial, that is, the insertion loss of IGZO in the initial state of the device is very small. This is a very important advantage of the IGZO Schottky diode for dynamic tuning of the metamaterial.

Claims

1. A method for dynamic tuning control of a metamaterial based on a Schottky diode, the Schottky diode including, from bottom to top, a Schottky electrode, an amorphous indium gallium zinc oxide (IGZO) active layer, and an ohmic electrode; the Schottky electrode is a metamaterial and has a gap that is a capacitive structure of the metamaterial; (1) disposing the IGZO active layer to cover the gap and form a Schottky barrier between the IGZO active layer and the Schottky electrode; (2) dynamically adjusting and controlling the metamaterial by applying a positive voltage to the Schottky electrode and a negative voltage to the ohmic electrode to increase the IGZO free carrier concentration of the IGZO active layer disposed in the step (1) and short-circuiting the gap; Including, The gap is less than 5 μm. A method for dynamic tuning control of a Schottky diode-based metamaterial.

2. The method for dynamic tuning control of metamaterials based on Schottky diodes as claimed in claim 1, wherein the material of the metamaterial includes Ti / Au / Pd.

3. 2. The method for dynamic tuning control of a Schottky diode based metamaterial of claim 1, wherein the metamaterial comprises a split-ring metamaterial or a split-ring metamaterial array.

4. The method further comprises the step (3), in which, under a zero bias condition of a voltage between the Schottky electrode and the ohmic electrode, the IGZO between the gaps is depleted to form an RLC circuit in the metamaterial, resulting in a bandstop response; The method for dynamically adjusting and controlling a metamaterial based on a Schottky diode according to any one of claims 1 to 3, characterized in that the short-circuiting of the gap in step (2) increases the transmittance of electromagnetic waves.

5. The Schottky diode (a) cleaning a substrate; (b) forming a Schottky electrode on the substrate cleaned in (a) using photolithography, e-beam evaporation, and lift-off techniques; (c) forming the IGZO active layer on the Schottky electrode formed in (b); and (d) forming an ohmic electrode, the material of which is Ti / Au and the thickness of which is 10 / 300 nm, on the IGZO active layer formed in step (c) by photolithography, e-beam evaporation and lift-off techniques.

6. 6. The method for dynamic tuning control of Schottky diode-based metamaterials of claim 5, wherein the step (a) includes first cleaning with a cleaning agent for 5 minutes, then cleaning with deionized water for 10 minutes, then cleaning with acetone for 5 minutes, then cleaning with ethanol for 5 minutes, then rinsing with deionized water, and finally blowing dry with nitrogen.

7. 6. The method for dynamic tuning control of Schottky diode-based metamaterials as claimed in claim 5, wherein the step (c) includes: transferring a pattern of the IGZO active layer onto the sample of step (b) by photolithography, putting the sample into a plasma cleaner to clean it with oxygen plasma for 30 minutes to create an oxygen-rich environment on the surface of the sample, and forming the IGZO active layer with a thickness of 750 nm by photolithography, magnetron sputtering, and lift-off techniques.

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