Photoelectric detector integrating ferroelectric polarization and plasma resonance effect and preparation method thereof

Abstract

The present invention proposes a photoelectric detector integrating ferroelectric polarization and plasma resonance effect and a preparation method thereof, wherein the photoelectric detector comprises a conductive substrate layer, a ferroelectric material layer, a non-precious metal plasma layer and a top electrode layer arranged in sequence from bottom to top. 3+ Nd doping, a rare earth element with similar valence and ionic radius, can inhibit Bi 3+ vacancies and oxygen vacancies without changing the Bi 4 Ti 3 O 12 structure, and at the same time form a one-dimensional nanofiber structure, which can increase the surface area. Compared with the commonly used ferroelectric thin film samples, it is more conducive to promoting the formation of a single domain structure, thereby improving the ferroelectric polarization performance; the use of non-precious metal nanosheets to self-assemble Bi metal microspheres can not only produce surface plasmon resonance similar to precious metal Au, enhance the electric field strength in the near-field region and the ability to capture linear light, but also save preparation costs to avoid the problem of metal nanoparticle agglomeration.

Description

Technical Field

[0001] The present invention relates to the field of optoelectronic information technology, and in particular to a photoelectric detector integrating ferroelectric polarization and plasma resonance effects and a preparation method thereof. Background Art

[0002] Photodetectors that convert light signals into electrical signals are one of the core components of the modern electronics industry and have important applications in the fields of health, industry and science, including medicine, space exploration, environmental monitoring, astronomy and secure communications. However, most of the photodetectors reported so far require an external power supply to start working, which undoubtedly restricts the development of photodetectors towards portability, energy saving and miniaturization.

[0003] Ferroelectric materials have a non-centrosymmetric crystal structure and a high spontaneous ferroelectric polarization intensity that can form a built-in electric field. 12 It is a type of single-phase multiferroic material that exhibits both ferroelectricity and ferromagnetism at room temperature or above. Its layered stacking makes it easy for its lattice to deform in the stacking direction, making it possible to regulate its own built-in electric field and improve its photoelectric conversion efficiency. 12 There are also disadvantages such as small residual polarization, large coercive field and high high temperature dielectric loss, which limit its application. In order to improve its performance, doping substitution is Bi4Ti3O 12 One of the most commonly used modification methods is to replace the volatile Bi with the rare earth element Nd, which is more chemically stable than Bi. By reducing the Bi content, oxygen vacancies can be reduced, thereby increasing the residual polarization.

[0004] In addition, the traditional straight photodetector has a weak ability to capture line light, which to some extent limits the further improvement of performance indicators such as the photodetector response rate. Therefore, improving light absorption is one of the most pressing issues. Precious metals such as Au and Ag, which are commonly used to enhance light absorption, are expensive and difficult to meet actual needs. The non-precious metal Bi also has a similar surface plasmon effect. Compared with precious metals such as Au and Ag, the non-precious metal Bi single metal has the advantages of simple preparation and low price, but it also has the problem of insufficient stability.

[0005] Based on this, it is necessary to solve many problems such as the need for external bias voltage in photodetectors, insufficient response sensitivity of ferroelectric materials, weak light absorption and expensive and complicated preparation process, and develop a low-cost technology for manufacturing photodetectors to obtain high-performance, self-driven photodetection devices based on ferroelectric materials. Summary of the invention

[0006] Based on this, the purpose of the present invention is to provide a photodetector that integrates ferroelectric polarization and plasma resonance effects to solve the current problems that restrict the development of ferroelectric photodetectors towards miniaturization and integration, such as the need for an external power supply, weak ferroelectric polarization ability and weak light absorption; and by constructing a nanosheet self-assembled Bi metal microsphere and a rare earth element Nd-doped ferroelectric Bi4Ti3O 12 Nanofibers, using ferroelectric polarization and plasma resonance effects to regulate and enhance the performance of self-driven photodetectors.

[0007] Specifically, the present invention provides a photodetector integrating ferroelectric polarization and plasma resonance effects, wherein the photodetector comprises a conductive substrate layer (1), a ferroelectric material layer (2), a non-precious metal plasma layer (3) and a top electrode layer (4) arranged in sequence from bottom to top;

[0008] The conductive substrate layer (1) is composed of a Pt-plated silicon substrate;

[0009] The ferroelectric material layer (2) is made of rare earth element Nd doped ferroelectric Bi4Ti3O 12 Nanofibers are used to enhance Bi4Ti3O by A-site ion doping and dimensionality control. 12 The ferroelectric polarization ability of the ferroelectric can be controlled by electric field.

[0010] The non-noble metal plasma layer (3) is composed of a nanosheet self-assembled Bi metal microsphere array, which is used to generate a noble metal-like plasma resonance effect to enhance the light absorption of the ferroelectric layer and reduce the device preparation cost;

[0011] The top electrode layer (4) is composed of an Au-plated electrode.

[0012] The photoelectric detector integrating ferroelectric polarization and plasma resonance effect, wherein, in the conductive substrate layer (1), the thickness of the Pt layer corresponding to the Pt plating is in the range of 300 to 500 nm.

[0013] The photoelectric detector integrating ferroelectric polarization and plasma resonance effect, wherein in the ferroelectric material layer (2), the ratio of the doping amount of Nd to the content of Bi is in the range of 1 to 8 mol%, and the Nd-doped Bi4Ti3O 12 The diameter of the nanofibers ranges from 50 to 200 nm, the thickness ranges from 200 to 1500 nm, and the ferroelectric polarization capacity ranges from 30 to 80 μC / cm 2 .

[0014] The photoelectric detector integrating ferroelectric polarization and plasma resonance effect, wherein in the non-precious metal plasma layer (3), in the nanosheet self-assembled Bi metal microspheres, the thickness of the nanosheets is in the range of 5 to 20 nm, and the diameter of the metal microspheres is in the range of 200 to 800 nm.

[0015] The photoelectric detector integrating ferroelectric polarization and plasma resonance effect, wherein in the top electrode layer (4), the thickness of the Au layer ranges from 300 to 500 nm.

[0016] The present invention also provides a method for preparing a photoelectric detector integrating ferroelectric polarization and plasma resonance effect, wherein the method for preparing the photoelectric detector integrating ferroelectric polarization and plasma resonance effect as described above comprises the following steps:

[0017] Step S1: Preparation of a conductive substrate layer:

[0018] The Pt layer was deposited on the silicon substrate by magnetron sputtering, wherein the purity of the Pt target was 99.99%;

[0019] Step S2: Preparation of ferroelectric material layer:

[0020] The rare earth element Nd-doped ferroelectric Bi4Ti3O 12 Nanofibers;

[0021] Step S3: Preparation of plasma layer:

[0022] The nanosheet self-assembled Bi metal microspheres were prepared by a one-step solvothermal method, and the nanosheet self-assembled Bi metal microspheres were uniformly dispersed in the Nd-doped Bi4Ti3O 12 The surface of the nanofibers;

[0023] Step S4: Preparation of top electrode layer:

[0024] The Au film was deposited as the top electrode by magnetron sputtering, where the purity of the Au target was 99.99%.

[0025] The method for preparing the photoelectric detector integrating ferroelectric polarization and plasma resonance effect, wherein in the step S2, the method for preparing the ferroelectric material layer comprises the following steps:

[0026] Precursor solution preparation: Dissolve bismuth acetate, neodymium nitrate and tetrabutyl titanate in a preset molar mass ratio in a mixed solvent of acetic acid and N,N-dimethylformamide in a volume ratio of 1:1, then add 1.25g of polyvinyl pyrrolidone and stir at room temperature for 6-12h to obtain Nd-doped ferroelectric Bi4Ti3O 12Nanofiber precursor solution;

[0027] Electrospinning nanofibers: The conductive substrate layer obtained in step S1 is used as a receiving substrate, the spinning voltage is controlled to be 8-18 KV, the distance between the spinneret and the receiving substrate is 8-18 cm, the propulsion speed is 0.01-0.1 mm / min, the relative humidity is 20%-40%, and Nd-doped ferroelectric Bi4Ti3O 12 Nanofiber precursors;

[0028] Heat treatment: Nd doped ferroelectric Bi4Ti3O 12 The nanofiber precursor is placed in a tube furnace, and the calcination temperature is controlled to be 500-600°C, the calcination time is 1-2h, and the heating rate is 1-3°C / min, so as to finally obtain Nd-doped ferroelectric Bi4Ti3O 12 Nanofibers.

[0029] The method for preparing the photoelectric detector integrating ferroelectric polarization and plasma resonance effect, wherein in the step S3, the method for preparing the plasma layer comprises the following steps:

[0030] Dissolve 0.1-0.6 g of bismuth nitrate in 10-40 mL of ethylene glycol to obtain a bismuth nitrate solution, and add 0.2-1 g of polyvinyl pyrrolidone; wherein the ethylene glycol is used as a reducing agent to reduce bismuth ions to bismuth element, and the polyvinyl pyrrolidone is used as a surfactant to self-assemble Bi nanosheets into microspheres;

[0031] The mixture is stirred at 100° C. for 2 to 12 hours, subjected to a solvent thermal reaction at 120 to 180° C. for 2 to 12 hours, cooled at room temperature, and washed with deionized water to obtain nanosheet self-assembled Bi metal microspheres.

[0032] The advantages of the present invention are:

[0033] (1) The present invention adopts Bi 3+ Nd doping, a rare earth element with similar valence and ionic radius, can inhibit Bi 3+ vacancies and oxygen vacancies without changing the Bi4Ti3O 12 The structure of the ferroelectric film is formed at the same time, and a one-dimensional nanofiber structure is formed, which can increase the surface area. Compared with the commonly used ferroelectric thin film samples, it is more conducive to promoting the formation of a single domain structure, thereby improving the ferroelectric polarization performance;

[0034] (2) The non-precious metal nanosheet self-assembled Bi metal microspheres used in the present invention can not only generate surface plasmon resonance similar to the precious metal Au, enhance the electric field strength in the near field region and the ability to capture linear light, but also save preparation costs to avoid the problem of metal nanoparticle agglomeration;

[0035] (3) Compared with the traditional PN junction, heterojunction and Schottky junction, the present invention achieves self-driven carrier separation through the built-in electric field of the interface, and the coupling ferroelectric polarization and plasma resonance effect enhance the self-driven photoelectric detection performance, and the direction of the photocurrent can be changed by changing the Bi4Ti3O 12 to switch the polarization direction.

[0036] Other features and advantages of the present disclosure will be set forth in the following description, or some features and advantages may be inferred or unambiguously determined from the description, or may be learned by implementing the above-mentioned technology of the present disclosure.

[0037] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 A schematic diagram of the structure of a photodetector enhanced by integrated ferroelectric polarization and plasma resonance effect constructed by the present invention;

[0039] Figure 2 The Nd-doped ferroelectric Bi4Ti3O synthesized in the first embodiment of the present invention 12 Scanning electron microscopy images of nanofibers;

[0040] Figure 3 The Nd-doped ferroelectric Bi4Ti3O synthesized in the first embodiment of the present invention 12 Ferroelectric hysteresis curve of nanofibers;

[0041] Figure 4 The Nd-doped ferroelectric Bi4Ti3O synthesized in the first embodiment of the present invention 12 The nanofibers were prepolarized at ±5 V and irradiated with a 390 nm laser (power 1.31 mW / cm 2 )’s current-time curve;

[0042] Figure 5 This is a scanning electron microscope image of the nanosheet self-assembled Bi metal microspheres synthesized in the first embodiment of the present invention;

[0043] Figure 6 Bi@Nd doped Bi4Ti3O synthesized in the first embodiment of the present invention 12 Nanofibers were irradiated with 390nm laser (power 1.31mW / cm 2 )’s current-time curve. DETAILED DESCRIPTION

[0044] In order to facilitate understanding of the present invention, the present invention will be described more fully below with reference to the relevant drawings. The preferred embodiments of the present invention are shown in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present invention more thorough and comprehensive.

[0045] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0046] See also Figure 1 The present invention provides a photodetector that integrates ferroelectric polarization and plasma resonance effects, wherein the photodetector comprises a conductive substrate layer (1), a ferroelectric material layer (2), a non-precious metal plasma layer (3) and a top electrode layer (4) arranged in sequence from bottom to top.

[0047] In the present invention, the above-mentioned conductive substrate layer (1) is composed of a silicon substrate plated with Pt. In the conductive substrate layer (1), the thickness of the Pt layer corresponding to the Pt plating is in the range of 300 to 500 nm.

[0048] In addition, the ferroelectric material layer (2) is made of rare earth element Nd doped ferroelectric Bi4Ti3O 12 The ferroelectric material layer (2) is used to enhance the Bi4Ti3O 12 The ferroelectric polarization ability of the material can be controlled by the electric field.

[0049] It should be noted that in the ferroelectric material layer (2), the ratio of the doping amount of Nd to the content of Bi is in the range of 1 to 8 mol%. 12 The diameter of the nanofibers ranges from 50 to 200 nm, the thickness ranges from 200 to 1500 nm, and the ferroelectric polarization capacity ranges from 30 to 80 μC / cm 2 .

[0050] Furthermore, the non-noble metal plasma layer (3) is composed of a nanosheet self-assembled Bi metal microsphere array. The non-noble metal plasma layer (3) is used to generate a noble metal-like plasma resonance effect to enhance the light absorption of the ferroelectric layer and reduce the device preparation cost.

[0051] It should be supplemented here that in the non-precious metal plasma layer (3), in the nanosheet self-assembled Bi metal microspheres, the thickness of the nanosheets ranges from 5 to 20 nm, and the diameter of the metal microspheres ranges from 200 to 800 nm.

[0052] Furthermore, the top electrode layer (4) is composed of an Au-plated electrode, that is, the top electrode layer (4) is an Au electrode.

[0053] In the top electrode layer (4), the thickness of the Au layer ranges from 300 to 500 nm.

[0054] The present invention also provides a method for preparing a photoelectric detector integrating ferroelectric polarization and plasma resonance effect, wherein the method for preparing the photoelectric detector integrating ferroelectric polarization and plasma resonance effect as described above comprises the following steps:

[0055] Step S1: Preparation of a conductive substrate layer:

[0056] The Pt layer is deposited on the silicon substrate by magnetron sputtering, wherein the purity of the Pt target is 99.99%.

[0057] Step S2: Preparation of ferroelectric material layer:

[0058] The rare earth element Nd-doped ferroelectric Bi4Ti3O 12 Nanofibers.

[0059] Specifically, in step S2, the method for preparing the ferroelectric material layer includes the following steps:

[0060] Precursor solution configuration:

[0061] The preset molar mass ratio of bismuth acetate, neodymium nitrate and tetrabutyl titanate was dissolved in a mixed solvent of acetic acid and N,N-dimethylformamide in a volume ratio of 1:1, and then 1.25g of polyvinyl pyrrolidone was added and stirred at room temperature for 6-12h to obtain Nd-doped ferroelectric Bi4Ti3O 12 Nanofiber precursor solution.

[0062] Electrospinning Nanofibers:

[0063] The conductive substrate layer obtained in step S1 is used as a receiving substrate, the spinning voltage is controlled to be 8-18 KV, the distance between the spinneret and the receiving substrate is 8-18 cm, the propulsion speed is 0.01-0.1 mm / min, the relative humidity is 20%-40%, and Nd-doped ferroelectric Bi4Ti3O is obtained by spinning. 12 Nanofiber Precursors.

[0064] Heat Treatment:

[0065] Nd doped ferroelectric Bi4Ti3O 12 The nanofiber precursor is placed in a tube furnace, and the calcination temperature is controlled to be 500-600°C, the calcination time is 1-2h, and the heating rate is 1-3°C / min, so as to finally obtain Nd-doped ferroelectric Bi4Ti3O 12 Nanofibers.

[0066] Step S3: Preparation of plasma layer:

[0067] The nanosheet self-assembled Bi metal microspheres were prepared by a one-step solvothermal method, and the nanosheet self-assembled Bi metal microspheres were uniformly dispersed in the Nd-doped Bi4Ti3O 12 The surface of nanofibers.

[0068] In step S3, the method for preparing the plasma layer comprises the following steps:

[0069] Dissolve 0.1-0.6 g of bismuth nitrate in 10-40 mL of ethylene glycol to obtain a bismuth nitrate solution, and add 0.2-1 g of polyvinyl pyrrolidone; wherein the ethylene glycol is used as a reducing agent to reduce bismuth ions to bismuth element, and the polyvinyl pyrrolidone is used as a surfactant to self-assemble Bi nanosheets into microspheres;

[0070] The mixture is stirred at 100° C. for 2 to 12 hours, subjected to a solvent thermal reaction at 120 to 180° C. for 2 to 12 hours, cooled at room temperature, and washed with deionized water to obtain nanosheet self-assembled Bi metal microspheres.

[0071] Step S4: Preparation of top electrode layer:

[0072] The Au film was deposited as the top electrode by magnetron sputtering, where the purity of the Au target was 99.99%.

[0073] The preparation method of the photoelectric detector integrating ferroelectric polarization and plasma resonance effect proposed by the present invention is described in detail below with reference to several specific embodiments.

[0074] Embodiment 1:

[0075] The first embodiment of the present invention provides a method for preparing a photoelectric detector integrating ferroelectric polarization and plasma resonance effect, which specifically includes the following steps:

[0076] Step S1: Preparation of a conductive substrate layer:

[0077] The Pt layer is deposited on the silicon substrate by magnetron sputtering, wherein the purity of the Pt target is 99.99%. In this embodiment, the thickness of the obtained Pt layer is 300 nm.

[0078] Step S2: Preparation of ferroelectric material layer:

[0079] The rare earth element Nd-doped ferroelectric Bi4Ti3O was prepared on the conductive substrate obtained in step S1 by using a sol-gel method, an electrospinning method and a high temperature calcination method. 12 Nanofiber, the specific steps include:

[0080] Precursor solution preparation: Dissolve bismuth acetate, neodymium nitrate and tetrabutyl titanate in a molar mass ratio of 3.8:0.2:3 in a mixed solvent of acetic acid and N,N-dimethylformamide in a volume ratio of 1:1, then add 1.25g of polyvinyl pyrrolidone and stir at room temperature for 12h to form Nd-doped ferroelectric Bi4Ti3O 12 Nanofiber precursor solution.

[0081] Electrospinning Nanofibers:

[0082] The conductive substrate layer obtained in step S1 was used as a receiving substrate, the spinning voltage was controlled to be 15 KV, the distance between the spinneret and the receiving substrate was 15 cm, the propulsion speed was 0.03 mm / min, the relative humidity was 30%, and Nd-doped ferroelectric Bi4Ti3O was obtained by spinning. 12 Nanofiber Precursors.

[0083] Heat Treatment:

[0084] Nd doped ferroelectric Bi4Ti3O 12 The nanofiber precursor was placed in a tube furnace, and the calcination temperature was controlled to be 550 °C, the calcination time was 1.5 h, and the heating rate was 2 °C / min. Finally, Nd-doped ferroelectric Bi4Ti3O 12 Nanofibers.

[0085] from Figure 2 It can be seen that after high-temperature calcination, with the volatilization and crystallization of polyvinyl pyrrolidone, ferroelectric nanofibers with good uniformity (Nd-doped ferroelectric Bi4Ti3O 12 Nanofibers). Moreover, the ferroelectric nanofibers have uniform size, controllable morphology, and a diameter concentrated at 120nm. Figure 3 As shown in the figure, an external electric field is applied to the obtained ferroelectric nanofibers. It can be seen that the polarization of the ferroelectric changes with the electric field strength. The polarization strength and the external electric field have a nonlinear relationship. The ferroelectric polarization capacity of the ferroelectric nanofibers is 33.13μC / cm 2 .

[0086] like Figure 4 As shown in the figure, the obtained ferroelectric nanofibers were plated with Au as the top electrode, and the devices were prepolarized at ±5 V for 5 min, respectively, and the 390 nm laser irradiation (power 1.31 mW / cm2 ) current-time curve. Figure 4 As shown in the figure, the photocurrent of the pre-polarized device is improved compared with that in the original state. The photocurrents under negative polarization and positive polarization reach -120.77nA and 57.9InA, which are 6 times and 2 times higher than that in the original state (photocurrent 22.55nA), respectively. It can be seen that ferroelectric polarization can regulate the photocurrent size and direction of the photodetection device.

[0087] Step S3: Preparation of plasma layer:

[0088] Nanosheet self-assembled Bi metal microspheres were prepared by a one-step solvothermal method. 0.48 g of bismuth nitrate was dissolved in 30 mL of ethylene glycol to obtain a bismuth nitrate solution, and 0.886 g of polyvinyl pyrrolidone was added. Ethylene glycol was used as a reducing agent to reduce bismuth ions to bismuth elemental substance, and polyvinyl pyrrolidone was used as a surfactant to self-assemble Bi nanosheets into microspheres. The solution was stirred at 100°C for 3 h, subjected to a solvothermal reaction at 160°C for 8 h, and then cooled to room temperature and washed with deionized water to obtain nanosheet self-assembled Bi metal microspheres.

[0089] like Figure 5 As shown, the method can prepare large-scale nanosheet self-assembled Bi metal microspheres with uniform size and uniform dispersion, wherein the thickness of the nanosheet is about 20nm and the diameter of the microsphere is about 500nm. Further, the spin coating titration method is used to uniformly disperse the Bi metal microspheres in the Nd-doped Bi4Ti3O 12 Nanofiber surface.

[0090] S4. Preparation of top electrode layer:

[0091] The Au film was deposited as the top electrode by magnetron sputtering, the purity of the Au target was 99.99%, and the thickness of the Au layer was 400 nm.

[0092] like Figure 6 As shown in the figure, the prepared optoelectronic device, under 390nm laser irradiation (power 1.31mW / cm 2 ) current-time curve, from which we can see that Bi@Bi 3.8 Nd 0.2 Ti3O 12 Photocurrent compared to Bi 3.8 Nd 0.2 Ti3O 12 Its photocurrent increased from -120.77nA to -500nA, an increase of 4.2 times, and compared with the original polarization state (photocurrent 22.55nA), it increased by nearly 22.2 times. Therefore, coupling ferroelectric polarization and plasma resonance effects can effectively improve the photoelectric detection performance.

[0093] Embodiment 2:

[0094] The second embodiment of the present invention provides a method for preparing a photoelectric detector integrating ferroelectric polarization and plasma resonance effect, which specifically comprises the following steps:

[0095] Step S1: Preparation of a conductive substrate layer:

[0096] The Pt layer is deposited on the Si substrate by magnetron sputtering, wherein the purity of the Pt target is 99.99%. In this embodiment, the thickness of the obtained Pt layer is 400 nm.

[0097] Step S2: Preparation of ferroelectric material layer:

[0098] The rare earth element Nd-doped ferroelectric Bi4Ti3O was prepared on the conductive substrate obtained in step S1 by using a sol-gel method, an electrospinning method and a high temperature calcination method. 12 Nanofiber, the specific steps include:

[0099] Precursor solution configuration:

[0100] Bismuth acetate, neodymium nitrate and tetrabutyl titanate with a molar mass ratio of 3.6:0.4:3 were dissolved in a mixed solvent of acetic acid and N,N-dimethylformamide with a volume ratio of 1:1, and then 1.25 g of polyvinyl pyrrolidone was added and stirred at room temperature for 10 h to form Nd-doped ferroelectric Bi4Ti3O 12 Nanofiber precursor solution.

[0101] Electrospinning Nanofibers:

[0102] The conductive substrate layer obtained in step S1 was used as a receiving substrate, the spinning voltage was controlled to be 10 KV, the distance between the spinneret and the receiving substrate was 15 cm, the propulsion speed was 0.03 mm / min, the relative humidity was 30%, and Nd-doped ferroelectric Bi4Ti3O was obtained by spinning. 12 Nanofiber Precursors.

[0103] Heat Treatment:

[0104] Nd doped ferroelectric Bi4Ti3O 12 The nanofiber precursor was placed in a tube furnace, and the calcination temperature was controlled to be 500 °C, the calcination time was 2 h, and the heating rate was 2 °C / min. Finally, Nd-doped ferroelectric Bi4Ti3O 12 Nanofibers.

[0105] Step S3: Preparation of plasma layer:

[0106] Nanosheet self-assembled Bi metal microspheres were prepared by a one-step solvothermal method. 0.4 g of bismuth nitrate was dissolved in 40 mL of ethylene glycol to obtain a bismuth nitrate solution, and 0.886 g of polyvinyl pyrrolidone was added. Ethylene glycol was used as a reducing agent to reduce bismuth ions to bismuth elemental substance, and polyvinyl pyrrolidone was used as a surfactant to self-assemble Bi nanosheets into microspheres. The mixture was stirred at 100°C for 2 h, subjected to a solvothermal reaction at 140°C for 8 h, and then cooled to room temperature and washed with deionized water to obtain nanosheet self-assembled Bi metal microspheres.

[0107] Furthermore, the Bi metal microspheres are uniformly dispersed in the Nd-doped Bi4Ti3O 12 Nanofiber surface.

[0108] Step S4: Preparation of top electrode layer:

[0109] The Au film was deposited as the top electrode by magnetron sputtering, the purity of the Au target was 99.99%, and the thickness of the Au layer was 400 nm.

[0110] Embodiment three:

[0111] The third embodiment of the present invention provides a method for preparing a photoelectric detector integrating ferroelectric polarization and plasma resonance effect, which specifically includes the following steps:

[0112] Step S1: Preparation of a conductive substrate layer:

[0113] The Pt layer is deposited on the silicon substrate by magnetron sputtering, wherein the purity of the Pt target is 99.99%. In this embodiment, the thickness of the obtained Pt layer is 300 nm.

[0114] Step S2: Preparation of ferroelectric material layer:

[0115] The rare earth element Nd-doped ferroelectric Bi4Ti3O was prepared on the conductive substrate obtained in step S1 by using a sol-gel method, an electrospinning method and a high temperature calcination method. 12 Nanofiber, the specific steps include:

[0116] Precursor solution configuration:

[0117] Bismuth acetate, neodymium nitrate and tetrabutyl titanate with a molar mass ratio of 3.5:0.5:3 were dissolved in a mixed solvent of acetic acid and N,N-dimethylformamide with a volume ratio of 1:1, and then 1.25 g of polyvinyl pyrrolidone was added and stirred at room temperature for 8 h to form Nd-doped ferroelectric Bi4Ti3O 12 Nanofiber precursor solution.

[0118] Electrospinning Nanofibers:

[0119] The conductive substrate layer obtained in step S1 was used as a receiving substrate, the spinning voltage was controlled to be 10 KV, the distance between the spinneret and the receiving substrate was 10 cm, the propulsion speed was 0.08 mm / min, the relative humidity was 30%, and Nd-doped ferroelectric Bi4Ti3O was obtained by spinning. 12 Nanofiber Precursors.

[0120] Heat Treatment:

[0121] Nd doped ferroelectric Bi4Ti3O 12 The nanofiber precursor was placed in a tube furnace, and the calcination temperature was controlled to be 600 °C, the calcination time was 2 h, and the heating rate was 3 °C / min. Finally, Nd-doped ferroelectric Bi4Ti3O 12 Nanofibers.

[0122] Step S3: Preparation of plasma layer:

[0123] Nanosheet self-assembled Bi metal microspheres were prepared by a one-step solvothermal method. 0.5 g of bismuth nitrate was dissolved in 40 mL of ethylene glycol to obtain a bismuth nitrate solution, and 0.886 g of polyvinyl pyrrolidone was added. Ethylene glycol was used as a reducing agent to reduce bismuth ions to bismuth elemental substance, and polyvinyl pyrrolidone was used as a surfactant to self-assemble Bi nanosheets into microspheres. The mixture was stirred at 100°C for 2 h, subjected to a solvothermal reaction at 160°C for 10 h, and then cooled to room temperature and washed with deionized water to obtain nanosheet self-assembled Bi metal microspheres.

[0124] Furthermore, the Bi metal microspheres are uniformly dispersed in the Nd-doped Bi4Ti3O 12 Nanofiber surface.

[0125] Step S4: Preparation of top electrode layer:

[0126] The Au film was deposited as the top electrode by magnetron sputtering, the purity of the Au target was 99.99%, and the thickness of the Au layer was 300 nm.

[0127] The advantages of the present invention are:

[0128] (1) The present invention adopts 3+ Nd doping, a rare earth element with similar valence and ionic radius, can inhibit Bi 3+ vacancies and oxygen vacancies without changing the Bi4Ti3O 12 The structure of the ferroelectric film is formed at the same time, and a one-dimensional nanofiber structure is formed, which can increase the surface area. Compared with the commonly used ferroelectric thin film samples, it is more conducive to promoting the formation of a single domain structure, thereby improving the ferroelectric polarization performance;

[0129] (2) The non-precious metal nanosheet self-assembled Bi metal microspheres used in the present invention can not only generate surface plasmon resonance similar to the precious metal Au, enhance the electric field strength in the near field region and the ability to capture linear light, but also save preparation costs to avoid the problem of metal nanoparticle agglomeration;

[0130] (3) Compared with the traditional PN junction, heterojunction and Schottky junction, the present invention achieves self-driven separation of carriers through the built-in electric field of the interface, and the coupling of ferroelectric polarization and plasma resonance effect enhances the self-driven photoelectric detection performance, and the direction of the photocurrent can be changed by changing the Bi4Ti3O 12 to switch the polarization direction.

[0131] Finally, it should be noted that the above-described embodiments are only specific implementations of the present invention, which are used to illustrate the technical solutions of the present invention, rather than to limit them. The protection scope of the present invention is not limited thereto. Although the present invention is described in detail with reference to the above-described embodiments, ordinary technicians in the field should understand that any technician familiar with the technical field can still modify the technical solutions recorded in the above-described embodiments within the technical scope disclosed by the present invention, or can easily think of changes, or make equivalent replacements for some of the technical features therein; and these modifications, changes or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A method for preparing a photodetector integrating ferroelectric polarization and plasma resonance effects, characterized in that: The method comprises the following steps: Step S1: Preparation of a conductive substrate layer: The Pt layer was deposited on the silicon substrate by magnetron sputtering, where the purity of the Pt target was 99.99%; Step S2: Preparation of ferroelectric material layer: The rare earth element Nd-doped ferroelectric Bi4Ti3O 12 Nanofibers; Step S3: Preparation of plasma layer: The nanosheet self-assembled Bi metal microspheres were prepared by a one-step solvothermal method, and the nanosheet self-assembled Bi metal microspheres were uniformly dispersed in the Nd-doped Bi4Ti3O 12 The surface of the nanofibers; Step S4: Preparation of top electrode layer: The Au film was deposited by magnetron sputtering as the top electrode, where the purity of the Au target was 99.99%; In step S2, the method for preparing the ferroelectric material layer comprises the following steps: Precursor solution preparation: Dissolve bismuth acetate, neodymium nitrate and tetrabutyl titanate in a preset molar mass ratio in a mixed solvent of acetic acid and N,N-dimethylformamide in a volume ratio of 1:1, then add 1.25 g of polyvinyl pyrrolidone and stir at room temperature for 6-12 hours to obtain Nd-doped ferroelectric Bi4Ti3O 12 Nanofiber precursor solution; Electrospinning nanofibers: The conductive substrate layer obtained in step S1 was used as a receiving substrate, the spinning voltage was controlled to be 8-18 KV, the distance between the spinneret and the receiving substrate was 8-18 cm, the propulsion speed was 0.01-0.1 mm / min, the relative humidity was 20%-40%, and Nd-doped ferroelectric Bi4Ti3O 12 Nanofiber precursors; Heat treatment: Nd doped ferroelectric Bi4Ti3O 12 The nanofiber precursor was placed in a tube furnace, and the calcination temperature was controlled to be 500-600 °C, the calcination time was 1-2 h, and the heating rate was 1-3 °C / min, so as to finally obtain Nd-doped ferroelectric Bi4Ti3O 12 Nanofibers; In step S3, the method for preparing the plasma layer comprises the following steps: Dissolve 0.1-0.6 g of bismuth nitrate in 10-40 mL of ethylene glycol to obtain a bismuth nitrate solution, and add 0.2-1 g of polyvinyl pyrrolidone; wherein the ethylene glycol is used as a reducing agent to reduce bismuth ions to bismuth element, and the polyvinyl pyrrolidone is used as a surfactant to self-assemble Bi nanosheets into microspheres; The mixture was stirred at 100°C for 2-12 hours, subjected to a solvothermal reaction at 120-180°C for 2-12 hours, cooled to room temperature, and washed with deionized water to obtain nanosheet self-assembled Bi metal microspheres.

2. A photodetector integrating ferroelectric polarization and plasma resonance effects, characterized in that: The photodetector is prepared by using the method for preparing a photodetector with integrated ferroelectric polarization and plasma resonance effect as described in claim 1, and the photodetector comprises a conductive substrate layer (1), a ferroelectric material layer (2), a non-precious metal plasma layer (3) and a top electrode layer (4) arranged in sequence from bottom to top; The conductive substrate layer (1) is composed of a Pt-plated silicon substrate; The ferroelectric material layer (2) is made of ferroelectric Bi4Ti3O doped with rare earth element Nd. 12 Nanofibers are used to enhance Bi4Ti3O by A-site ion doping and dimensionality control. 12 The ferroelectric polarization ability of the ferroelectric can be controlled by electric field. The non-noble metal plasma layer (3) is composed of a nanosheet self-assembled Bi metal microsphere array, which is used to generate a noble metal-like plasma resonance effect to enhance the light absorption of the ferroelectric layer and reduce the device preparation cost; The top electrode layer (4) is composed of an Au-plated electrode.

3. The photoelectric detector integrating ferroelectric polarization and plasma resonance effect according to claim 2, characterized in that: In the conductive substrate layer (1), the thickness of the Pt layer corresponding to Pt plating is in the range of 300-500 nm.

4. The photoelectric detector integrating ferroelectric polarization and plasma resonance effect according to claim 2, characterized in that: In the ferroelectric material layer (2), the ratio of the doping amount of Nd to the content of Bi is in the range of 1-8 mol%. 12 The diameter of the nanofibers ranges from 50 to 200 nm, the thickness ranges from 200 to 1500 nm, and the ferroelectric polarization capacity ranges from 30 to 80 μC / cm 2 .

5. The photoelectric detector integrating ferroelectric polarization and plasma resonance effect according to claim 2, characterized in that: In the non-precious metal plasma layer (3), in the nanosheet self-assembled Bi metal microspheres, the thickness of the nanosheets ranges from 5 to 20 nm, and the diameter of the metal microspheres ranges from 200 to 800 nm.

6. The photoelectric detector integrating ferroelectric polarization and plasma resonance effect according to claim 2, characterized in that: In the top electrode layer (4), the Au layer has a thickness ranging from 300 to 500 nm.

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