Flexoelectrically controlled field effect transistor and preparation method thereof

Abstract

The invention relates to the technical field of semiconductor devices, in particular to a flexoelectric control field effect transistor and a preparation method thereof. The field effect transistor of the present invention comprises: a substrate having a groove; the two-dimensional material layer is arranged on one side, close to the groove, of the substrate and covers the groove; the two-dimensional material layer comprises a conductive two-dimensional material; a first electrode; a second electrode; the first electrode and the second electrode are arranged at the two ends, opposite to the groove, of the two-dimensional material layer respectively, and both the first electrode and the second electrode make contact with the substrate; the shortest distance between the first electrode and the central axis of the groove is different from the shortest distance between the second electrode and the central axis of the groove. The interface barrier height of the flexoelectric regulation and control field effect transistor is smaller than that of a traditional field effect transistor, the carrier transport capacity is improved, the output characteristic of the transistor is further regulated and controlled, and the characteristic that the unidirectional current is adjustable is shown.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor devices, and particularly to a flexoelectricity-regulated field-effect transistor and a preparation method thereof. Background Art

[0002] In the field of modern electronic technology, the field-effect transistor (FET) is used as a basic component and is widely applied in various electronic devices and circuits. With the continuous development of microelectronic technology, the requirements for the performance of transistors are also constantly increasing. Due to their unique physical properties and excellent electronic properties, two-dimensional materials have gradually become a research hotspot for a new generation of electronic devices. As a typical two-dimensional transition metal dichalcogenide material, molybdenum disulfide (MoS₂) is considered an ideal material for constructing high-performance field-effect transistors because of its good semiconductor characteristics, high electron mobility, and large bandgap.

[0003] Traditional MoS₂ field-effect transistors usually adopt a symmetric structure, and their output characteristic curves also show symmetry. However, in practical applications, achieving unidirectional tunability of the transistor output characteristics is of great significance for constructing new electronic devices, improving device integration, and functional diversity. Traditional methods are difficult to effectively break this symmetry, which limits the application of MoS₂ field-effect transistors in complex electronic circuits. The flexoelectric effect refers to the phenomenon that when a material is subjected to mechanical stress (such as bending, stretching, etc.), an electric field or potential change will occur inside the material. This effect can regulate the electrical properties of the material through an external mechanical force and break the above symmetry.

[0004] Therefore, it is urgent to develop a flexoelectricity-regulated field-effect transistor and a preparation method thereof. Summary of the Invention

[0005] The present invention aims to solve at least one of the technical problems in the related art to some extent. For this purpose, the present invention provides a flexoelectricity-regulated field-effect transistor and a preparation method thereof. The flexoelectricity-regulated field-effect transistor of the present invention exhibits the characteristic of unidirectional current tunability.

[0006] For this purpose, in a first aspect of the present invention, a flexoelectricity-regulated field-effect transistor is provided, including:

[0007] A substrate having a groove;

[0008] A two-dimensional material layer disposed on one side of the substrate close to the groove and covering the groove; the two-dimensional material layer includes a conductive two-dimensional material;

[0009] A first electrode;

[0010] The second electrode; the first electrode and the second electrode are respectively disposed at two ends of the two-dimensional material layer relative to the groove, and both the first electrode and the second electrode are in contact with the substrate;

[0011] The distance between the first electrode and the central axis of the groove is different from the distance between the second electrode and the central axis of the groove.

[0012] The interfacial barrier height of the flexoelectricity-regulated field-effect transistor of the present invention is less than that of the conventional field-effect transistor, which improves the carrier transport ability, thereby regulating the output characteristics of the transistor, breaking the symmetry of the output curve of the conventional transistor, presenting the characteristic of adjustable unidirectional current, and having the advantages of simple structure and strong regulation ability.

[0013] In some embodiments of the present invention, the shortest distance between the first electrode and the central axis of the groove is greater than the shortest distance between the second electrode and the central axis of the groove.

[0014] In some embodiments of the present invention, the difference between the shortest distance between the first electrode and the central axis of the groove and the shortest distance between the second electrode and the central axis of the groove is 1-3 μm.

[0015] In some embodiments of the present invention, the conductive two-dimensional material includes one or more of molybdenum disulfide (MoS2), tungsten diselenide (WSe2), molybdenum diselenide (MoSe2), tungsten disulfide (WS2), tungsten diselenide (WSe2), platinum diselenide (PtSe2), molybdenum ditelluride (MoTe2), tungsten ditelluride (WTe2), vanadium diselenide (VSe2), chromium disulfide (CrS2), chromium diselenide (CrSe2), black phosphorus (BP), silicene, germanene, two-dimensional metal nanosheets (for example, silver nanosheets (Ag), gold nanosheets (Au)), transition metal carbides (MXene).

[0016] In some embodiments of the present invention, the thickness of the two-dimensional material layer is 0.7-50 nm.

[0017] In some embodiments of the present invention, the groove is filled with air. The two-dimensional material covering the groove area naturally sags, forming a huge strain gradient, thereby inducing flexoelectric polarization.

[0018] In some embodiments of the present invention, the horizontal distance from the central axis of the groove to the edge of the groove is 1-2 μm.

[0019] In some embodiments of the present invention, the depth of the groove is 1-2 μm.

[0020] In some embodiments of the present invention, the cross-sectional shape of the groove in the width direction is any one of a circle, a rectangle, an ellipse, and a polygon.

[0021] In some embodiments of the present invention, the substrate includes a silicon dioxide layer and a silicon layer, and the silicon dioxide layer is disposed on the side close to the two-dimensional material layer.

[0022] In some embodiments of the present invention, in the substrate, the thickness of the silicon dioxide layer is 100 - 300 nm, and the thickness of the silicon layer is 100 - 500 μm.

[0023] In some embodiments of the present invention, a part of the first electrode covers the substrate, and another part covers one end of the two-dimensional material layer relative to the groove; a part of the second electrode covers the substrate, and another part covers the other end of the two-dimensional material layer relative to the groove.

[0024] In some embodiments of the present invention, the material of the first electrode includes gold; the material of the second electrode includes gold.

[0025] The second aspect of the present invention provides a method for manufacturing the above-mentioned flexoelectricity-regulated field-effect transistor, including the following steps:

[0026] Prepare a substrate with a groove;

[0027] Dispose a two-dimensional material layer on one side of the substrate and cover the groove; the two-dimensional material layer includes a conductive two-dimensional material;

[0028] Dispose a first electrode and a second electrode at both ends of the two-dimensional material layer relative to the groove respectively. Both the first electrode and the second electrode are in contact with the substrate, and the shortest distance between the first electrode and the central axis of the groove is different from the shortest distance between the second electrode and the central axis of the groove, thereby obtaining a flexoelectricity-regulated field-effect transistor.

[0029] The additional aspects and advantages of the present invention will be partially given in the following description, partially become obvious from the following description, or be understood through the practice of the present invention. Description of the Drawings

[0030] The above and / or additional aspects and advantages of the present invention will become obvious and easy to understand from the description of the embodiments in conjunction with the following drawings, wherein:

[0031] Figure 1 Shows a schematic structural diagram of a flexoelectricity-regulated field-effect transistor according to an embodiment of the present invention;

[0032] Figure 2Shows a schematic diagram of the interfacial barrier of the first electrode contact in a flexoelectricity-regulated field-effect transistor according to an embodiment of the present invention;

[0033] Figure 3 Shows a flowchart for fabricating a flexoelectricity-regulated field-effect transistor according to an embodiment of the present invention;

[0034] Figure 4 Shows the output curve of the flexoelectricity-regulated field-effect transistor of Example 1 of the present invention;

[0035] Figure 5 Shows the output curve of the flexoelectricity-regulated field-effect transistor of Example 2 of the present invention;

[0036] Figure 6 Shows the output curve of the flexoelectricity-regulated field-effect transistor of Comparative Example 1 of the present invention.

[0037] Explanation of reference numerals:

[0038] 01: Substrate; 02: Two-dimensional material layer; 03: Second electrode; 04: Groove; 05: First electrode. Detailed description of the specific implementation

[0039] The embodiments of the present invention will be described in detail below. The following described embodiments are exemplary and are only used to explain the present invention and should not be construed as a limitation to the present invention.

[0040] It should be noted that the terms "first" and "second" are only used for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. Further, in the description of the present invention, unless otherwise specified, the meaning of "a plurality" is two or more.

[0041] The first aspect of the present invention provides a flexoelectricity-regulated field-effect transistor, comprising:

[0042] A substrate having a groove;

[0043] A two-dimensional material layer provided on one side of the substrate close to the groove and covering the groove; the two-dimensional material layer includes a conductive two-dimensional material;

[0044] A first electrode;

[0045] A second electrode; the first electrode and the second electrode are respectively provided at two ends of the two-dimensional material layer relative to the groove, and both the first electrode and the second electrode are in contact with the substrate;

[0046] The shortest distance between the first electrode and the central axis of the groove is different from the shortest distance between the second electrode and the central axis of the groove.

[0047] The interfacial barrier height of the flexoelectricity-regulated field-effect transistor of the present invention is less than that of the conventional field-effect transistor, which improves the carrier transport ability, and then regulates the output characteristics of the transistor, breaks the symmetry of the output curve of the conventional transistor, and presents the characteristic of adjustable unidirectional current. It has the advantages of simple structure and strong regulation ability.

[0048] In some embodiments of the present invention, the structure of the flexoelectricity-regulated field-effect transistor is as Figure 1 shown. It can be seen that the flexoelectricity-regulated field-effect transistor includes: a substrate 01 having a groove 04; a two-dimensional material layer 02 disposed on the side of the substrate close to the groove and covering the groove; a first electrode 05; a second electrode 03; the first electrode 05 and the second electrode 03 are respectively located at two ends of the two-dimensional material layer relative to the groove, and both the first electrode 05 and the second electrode 03 are in contact with the substrate 01.

[0049] In some embodiments of the present invention, the shortest distance between the first electrode and the central axis of the groove is greater than the shortest distance between the second electrode and the central axis of the groove.

[0050] In some embodiments of the present invention, the difference between the shortest distance between the first electrode and the central axis of the groove and the shortest distance between the second electrode and the central axis of the groove is 1-3 μm. As an example, the difference between the shortest distance between the first electrode and the central axis of the groove and the shortest distance between the second electrode and the central axis of the groove can be 1, 1.5, 2, 2.5, 3 μm.

[0051] In some embodiments of the present invention, the conductive two-dimensional material includes one or more of molybdenum disulfide (MoS2), tungsten diselenide (WSe2), molybdenum diselenide (MoSe2), tungsten disulfide (WS2), tungsten diselenide (WSe2), platinum diselenide (PtSe2), molybdenum ditelluride (MoTe2), tungsten ditelluride (WTe2), vanadium diselenide (VSe2), chromium disulfide (CrS2), chromium diselenide (CrSe2), black phosphorus (BP), silicene, germanene, two-dimensional metal nanosheets (for example, silver nanosheets (Ag), gold nanosheets (Au)), transition metal carbides (MXene); further, the conductive two-dimensional material includes molybdenum disulfide.

[0052] In some embodiments of the present invention, the thickness of the two-dimensional material layer is 0.7 - 50 nm. As an example, the thickness of the two-dimensional material layer can be 0.7, 0.8, 0.9, 1, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 25, 30, 35, 40, 45, 50 nm.

[0053] In some embodiments of the present invention, there is no special limitation on the filling material in the groove, and it is defaulted to air.

[0054] In some embodiments of the present invention, the horizontal distance from the central axis of the groove to the edge of the groove is 1 - 2 μm. As an example, the horizontal distance from the central axis of the groove to the edge of the groove can be 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2 μm.

[0055] In some preferred embodiments of the present invention, the horizontal distance from the central axis of the groove to the edge of the groove is 1.5 - 2 μm.

[0056] In some embodiments of the present invention, the depth of the groove is 1 - 2 μm. As an example, the depth of the groove can be 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2 μm. Grooves with a certain width and depth cause the two-dimensional material covering the groove area to sag naturally, forming a huge strain gradient, thereby inducing flexoelectric polarization.

[0057] In some embodiments of the present invention, the shape of the cross-section of the groove in the width direction is any one of a circle, a rectangle, an ellipse, and a polygon.

[0058] In some embodiments of the present invention, the groove is a cylindrical hole. At this time, the cross-section of the groove in the width direction is a rectangle, and the horizontal distance from the central axis of the groove to the edge of the groove can be understood as the radius of the hole of the groove.

[0059] In some embodiments of the present invention, the substrate includes a silicon dioxide layer and a silicon layer, and the silicon dioxide layer is disposed on the side close to the two-dimensional material layer.

[0060] In some embodiments of the present invention, in the substrate, the thickness of the silicon dioxide layer is 100 - 300 nm. As an example, the thickness of the silicon dioxide layer can be 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 250, 300 nm.

[0061] In some embodiments of the present invention, in the substrate, the thickness of the silicon layer is 100 - 500 μm. As an example, the thickness of the silicon layer can be 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 250, 300, 350, 400, 450, 500 μm.

[0062] In some embodiments of the present invention, a part of the first electrode covers the substrate, and another part covers one end of the two-dimensional material layer relative to the groove; a part of the second electrode covers the substrate, and another part covers the other end of the two-dimensional material layer relative to the groove.

[0063] In some embodiments of the present invention, the material of the first electrode includes gold; the material of the second electrode includes gold.

[0064] In some embodiments of the present invention, a schematic diagram of the interface barrier where two-dimensional MoS2 contacts the first electrode is as Figure 2 shown, where E F is the Fermi level of the first electrode, CB and VB are respectively the conduction band top and valence band bottom of two-dimensional MoS2, the dashed line is the interface barrier of a traditional field-effect transistor, is the interface barrier height of a traditional field-effect transistor, is the interface barrier height of the flexoelectricity-regulated field-effect transistor of the present invention. Flexoelectric polarization makes decrease, less than the interface barrier height of a traditional field-effect transistor, improving the carrier transport ability, and thus regulating the output characteristics of the transistor.

[0065] The second aspect of the present invention provides a method for manufacturing the above-mentioned flexoelectricity-regulated field-effect transistor, including the following steps:

[0066] S100. Prepare a substrate with a groove.

[0067] In some embodiments of the present invention, a groove is formed on the substrate, and the groove can be etched on the substrate by means of ultraviolet lithography, electron beam lithography, reactive ion etching or inductively coupled plasma etching.

[0068] In some embodiments of the present invention, the groove is filled with air. The two-dimensional material covering the groove area naturally sags, forming a large strain gradient, thereby inducing flexoelectric polarization.

[0069] In some embodiments of the present invention, the depth of the groove is 1 - 2 μm. As an example, the depth of the groove can be 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2 μm.

[0070] In some embodiments of the present invention, the cross-sectional shape of the groove in the width direction is any one of a circle, a rectangle, an ellipse, and a polygon.

[0071] In some embodiments of the present invention, the substrate includes a silicon dioxide layer and a silicon layer; the silicon dioxide layer is disposed on the side close to the two-dimensional material layer.

[0072] In some embodiments of the present invention, in the substrate, the thickness of the silicon dioxide layer is 100 - 300 nm.

[0073] In some embodiments of the present invention, in the substrate, the thickness of the silicon layer is 100 - 500 μm.

[0074] S200. Dispose the two-dimensional material layer on one side of the substrate and cover the groove; the two-dimensional material layer includes a conductive two-dimensional material.

[0075] In some embodiments of the present invention, the two-dimensional material layer is disposed on one side of the substrate by a mechanical exfoliation method or a chemical vapor deposition method.

[0076] In some embodiments of the present invention, disposing the two-dimensional material layer on one side of the substrate by a mechanical exfoliation method and covering the groove specifically includes:

[0077] Stick a MoS2 crystal with tape to obtain two-dimensional MoS2 disposed on the tape, and use polydimethylsiloxane (PDMS) to remove the two-dimensional MoS2 from the tape; transfer the two-dimensional MoS2 to a substrate with a groove, heat to reduce the viscosity of the PDMS, and separate the PDMS and the two-dimensional MoS2.

[0078] In some embodiments of the present invention, the conductive two-dimensional material includes one or more of molybdenum disulfide (MoS2), tungsten diselenide (WSe2), molybdenum diselenide (MoSe2), tungsten disulfide (WS2), tungsten diselenide (WSe2), platinum diselenide (PtSe2), molybdenum ditelluride (MoTe2), tungsten ditelluride (WTe2), vanadium diselenide (VSe2), chromium disulfide (CrS2), chromium diselenide (CrSe2), black phosphorus (BP), silicene, germanene, two-dimensional metal nanosheets (for example, silver nanosheets (Ag), gold nanosheets (Au)), and transition metal carbides (MXene); further, the conductive two-dimensional material includes molybdenum disulfide.

[0079] In some embodiments of the present invention, the thickness of the two-dimensional material layer is 0.7 - 50 nm.

[0080] S300. A first electrode and a second electrode are respectively disposed at two ends of the two-dimensional material layer relative to the groove. Both the first electrode and the second electrode are in contact with the substrate, and the shortest distance between the first electrode and the central axis of the groove is different from the shortest distance between the second electrode and the central axis of the groove, thereby obtaining a flexoelectricity-regulated field-effect transistor.

[0081] In some embodiments of the present invention, the first electrode is prepared by evaporation coating; the second electrode is prepared by evaporation coating.

[0082] In some embodiments of the present invention, the evaporation coating method includes: first evaporating an adhesion layer, and then evaporating a metal electrode; the evaporation rate is 0.1 - 0.5 nm / s.

[0083] In some embodiments of the present invention, a part of the first electrode covers the substrate, and another part covers one end of the two-dimensional material layer relative to the groove; a part of the second electrode covers the substrate, and another part covers the other end of the two-dimensional material layer relative to the groove.

[0084] In some embodiments of the present invention, the material of the first electrode includes gold; the material of the second electrode includes gold.

[0085] In some embodiments of the present invention, before the first electrode and the second electrode are respectively disposed at two ends of the two-dimensional material layer relative to the groove, the preparation method of the flexoelectricity-regulated field-effect transistor further includes the following steps carried out in sequence: applying photoresist, drying, exposing, developing, and removing the photoresist.

[0086] In some embodiments of the present invention, the step of applying photoresist is carried out by spin coating;

[0087] The application of photoresist specifically includes:

[0088] Drop the photoresist onto the surface of the two-dimensional material layer, spin coat at a low speed for 5 - 10 s first, and then spin coat at a high speed for 20 - 50 s. The rotation speed of the low-speed spin coating is 500 - 600 rpm; the rotation speed of the high-speed spin coating is 4000 - 5000 rpm; the amount of the dropped photoresist is 1.5 - 3 mL.

[0089] In some embodiments of the present invention, the drying temperature is 100 - 150 °C, and the time is 90 - 120 s.

[0090] In some embodiments of the present invention, ultraviolet lithography machine is used for the exposure, and the precise alignment of the mask pattern and the MoS2 channel region is achieved through an optical microscope, and the exposure time is 5 - 10 s.

[0091] In some embodiments of the present invention, the developer used for development includes one or more of tetramethylammonium hydroxide, tetrabutylammonium hydroxide, ethyltrimethylammonium hydroxide, choline hydroxide, and tris(2-hydroxyethyl)methylammonium hydroxide.

[0092] In some embodiments of the present invention, the photoresist stripping is carried out using an organic solvent; the organic solvent includes N-methylpyrrolidone.

[0093] The solutions of the present disclosure will be explained below with reference to examples. Those skilled in the art will understand that the following examples are only for illustrating the present disclosure and should not be regarded as limiting the scope of the present disclosure. For those not specified in the examples regarding specific techniques or conditions, they shall be carried out according to the techniques or conditions described in the literature in this field or according to the product specifications. For the reagents or instruments not specified as to the manufacturer, they are all conventional products that can be obtained through commercial purchase.

[0094] Example 1

[0095] The flexoelectricity-regulated field-effect transistor of this example is composed of a substrate and a two-dimensional MoS2 layer stacked in sequence. The substrate has a cylindrical groove. The first electrode is located on the right side of the two-dimensional material layer relative to the groove, and the second electrode is located on the left side of the two-dimensional material layer relative to the groove. Both the first electrode and the second electrode are in contact with the substrate; the substrate includes a silicon dioxide layer and a silicon layer. The silicon dioxide layer is in contact with the two-dimensional MoS2 layer. The thickness of the silicon layer is 500 μm, the thickness of the silicon dioxide layer is 285 nm, the depth of the groove is 1 μm, the pore diameter is 4 μm, and the thickness of the two-dimensional MoS2 layer is 10 nm.

[0096] The preparation process of the flexoelectricity-regulated field-effect transistor of this example is as Figure 3 shown and specifically includes the following steps:

[0097] (1) Preparation of the groove: First, perform a photolithography process, then use a reactive ion etcher (RIE) to etch the silicon dioxide layer by 285 nm, use a deep reactive ion etcher to etch the silicon layer by 715 nm, with a total etching depth of 1 μm, and finally remove the photoresist.

[0098] (2) Transfer of two-dimensional MoS2 onto the grooved substrate: Use a special blue tape for mechanical exfoliation to thin the MoS2 crystal, then use low-viscosity polydimethylsiloxane (PDMS) to remove the two-dimensional MoS2 from the blue tape; finally, use a two-dimensional material positioning and transfer platform to transfer the two-dimensional MoS2 onto the substrate, heat it to further reduce the viscosity of the PDMS, and separate the PDMS and the two-dimensional MoS2, thus successfully transferring the two-dimensional MoS2 onto the substrate.

[0099] (3) Preparation of the first electrode Au and the second electrode Au:

[0100] ① Photoresist coating: Use positive photoresist (AZ 5214), with a dropping volume of 1.5 mL. First, perform low-speed pre-spin coating (500 rpm, 5 s), and then high-speed (4000 rpm, 30 s) spin coating.

[0101] ② Pre-baking: Place the substrate with the coated photoresist on a hot plate, set the temperature to 110 °C, and bake for 90 s.

[0102] ③ Alignment exposure: Use an ultraviolet lithography machine to achieve precise alignment of the mask pattern with the MoS2 channel region through an optical microscope. Expose for 5 s, and control the horizontal distance between the left side of the first electrode and the central axis of the hole to be 3 μm, and the horizontal distance between the right side of the second electrode and the central axis of the hole to be 5 μm.

[0103] ④ Development, inspection: Use a 0.38% aqueous solution of tetramethylammonium hydroxide (TMAH), with a development time of 45 s. Use a high-resolution microscope to detect the integrity of the developed pattern.

[0104] ⑤ Thermal evaporation of gold: Simultaneously prepare the first electrode Au and the second electrode Au. First, evaporate chromium as an adhesion layer with a thickness of 5 nm, and then evaporate gold. The evaporation rate is maintained at 0.1 nm / s. The thickness of the first electrode gold and the second electrode gold is 50 nm.

[0105] ⑥ Photoresist removal, inspection process: Immerse the sample in N-methylpyrrolidone (NMP) for 45 minutes to dissolve the photoresist, obtaining a flexoelectricity-regulated field-effect transistor. Use a high-resolution microscope to observe the integrity of the metal pattern.

[0106] Example 2

[0107] The field-effect transistor in this example is only different from that in Example 1 in that: the hole diameter is 2 μm; the remaining steps are carried out according to the method in Example 1. The obtained field-effect transistor has a groove structure with a hole diameter of 2 μm.

[0108] Comparative Example 1

[0109] The field-effect transistor in this comparative example is only different from that in Example 1 in that: this comparative example omits step (1); the remaining steps are carried out according to the method in Example 1. The obtained field-effect transistor in this comparative example has no groove structure.

[0110] Test Example

[0111] Use a semiconductor parameter analyzer to test the output characteristics of the field-effect transistors obtained in Examples 1, 2, and Comparative Example 1. The first electrode Au and the second electrode Au are connected to the channels of the semiconductor parameter analyzer SMU (Source Measurement Unit) through micro-nano probes, and the gate is connected to the high-voltage SMU. After calibration, perform the test, and the scanning range is VDS (Source-drain voltage) is -0.8 to 0.8 V, and the gate voltage V GS is set to -10 V, 0 V, and 10 V.

[0112] The test results are as Figures 4 - 6 shown, Figure 4 where the abscissa is the source-drain voltage and the ordinate is the output current. It can be seen from Figure 4 that the field-effect transistor obtained in Example 1 breaks the characteristic of the symmetric output curve of the traditional transistor and presents the characteristic of adjustable unidirectional current.

[0113] It can be seen from Figure 5 that the field-effect transistor obtained in Example 2 also breaks the characteristic of the symmetric output curve of the traditional transistor and presents the characteristic of adjustable unidirectional current, proving that the method of using different shortest distances between the first electrode and the central axis of the groove and the shortest distance between the second electrode and the central axis of the groove can effectively regulate the output characteristics of the field-effect transistor.

[0114] Further analyze the transconductance (gm) of the field-effect transistors in Example 1 and Example 2:

[0115] gm = ΔI DS / ΔV GS

[0116] where I DS is the source-drain current and V GS is the gate voltage.

[0117] Calculate the transconductance (gm) at V DS = -0.5 V. The transconductance gm of the field-effect transistor in Example 1 is -39.9 pA / V, and the transconductance gm of the field-effect transistor in Example 2 is -13.6 pA / V. The results show that the gate voltage control sensitivity of the field-effect transistor in Example 1 is higher.

[0118] It can be seen from Figure 6 that under the regulation of the gate voltage V GS , both the positive and negative outputs of the source-drain voltage V DS can be adjusted, presenting the characteristic of adjustable traditional bidirectional current. Further calculate the transconductance (gm) of the field-effect transistor in Comparative Example 1. At V DS = -0.5 V, gm = -25.8 pA / V. The experimental results of Example 1, Example 2, and Comparative Example 1 show that when the pore diameter (4 μm) is appropriate, the flexoelectrically regulated field-effect transistor can improve the gate voltage control sensitivity of the device.

[0119] For the flexoelectrically regulated field-effect transistor of Example 1 of the present invention, under illumination with different powers of a 405 nm wavelength laser source, its output current IDS . That is to say, this flexoelectrically regulated field-effect transistor has three methods for adjustable output, namely source-drain voltage V DS、 gate voltage V GS and laser source power. Conventional field-effect transistors only have two methods for adjustable output, namely gate voltage V GS and laser source power. Based on this, four conventional field-effect transistors are required to implement NAND and NOR gate logic functions, while a single device of the present invention can implement NAND and NOR gate logic functions.

[0120] In the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "examples", "specific examples", "some implementation manners" or "some examples", etc. means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0121] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A flexoelectrically regulated field effect transistor, characterized in that, Comprising: A substrate with a groove; A two-dimensional material layer disposed on a side of the substrate close to the groove and covering the groove; the two-dimensional material layer includes a conductive two-dimensional material; A first electrode; A second electrode; The first electrode and the second electrode are respectively disposed at two ends of the two-dimensional material layer relative to the groove, and both the first electrode and the second electrode are in contact with the substrate; The shortest distance between the first electrode and the central axis of the groove is different from the shortest distance between the second electrode and the central axis of the groove.

2. The flexoelectricity-regulated field-effect transistor according to claim 1, wherein The shortest distance between the first electrode and the central axis of the groove is greater than the shortest distance between the second electrode and the central axis of the groove.

3. The flexoelectrically regulated field effect transistor according to claim 2, wherein The difference between the shortest distance between the first electrode and the central axis of the groove and the shortest distance between the second electrode and the central axis of the groove is 1 - 3 μm.

4. The flexoelectrically regulated field effect transistor according to claim 1, characterized in that, The conductive two-dimensional material includes one or more of molybdenum disulfide, tungsten diselenide, molybdenum diselenide, tungsten disulfide, tungsten diselenide, platinum diselenide, molybdenum ditelluride, tungsten ditelluride, vanadium diselenide, chromium disulfide, chromium diselenide, black phosphorus, silicene, germanene, two-dimensional metal nanosheets, transition metal carbides; And / or, the thickness of the two-dimensional material layer is 0.7 - 50 nm.

5. The flexoelectricity-regulated field effect transistor according to claim 1, characterized in that The horizontal distance from the central axis of the groove to the side of the groove is 1 - 2 μm; And / or, the depth of the groove is 1 - 2 μm.

6. The flexoelectricity-regulated field-effect transistor according to claim 1, wherein The substrate includes a silicon dioxide layer and a silicon layer, and the silicon dioxide layer is disposed on a side close to the two-dimensional material layer.

7. The flexoelectrically controlled field effect transistor according to claim 6, wherein In the substrate, the thickness of the silicon dioxide layer is 100 - 300 nm, and the thickness of the silicon layer is 100 - 500 μm.

8. The flexoelectrically regulated field effect transistor according to claim 1, characterized in that A part of the first electrode covers the substrate, and another part covers one end of the two-dimensional material layer relative to the groove; a part of the second electrode covers the substrate, and another part covers the other end of the two-dimensional material layer relative to the groove.

9. The flexoelectrically regulated field effect transistor according to claim 1, characterized in that, The material of the first electrode includes gold; the material of the second electrode includes gold.

10. A preparation method of a flexoelectricity-regulated field effect transistor, characterized in that, Including the following steps: Preparing a substrate with a groove; Disposing a two-dimensional material layer on one side of the substrate and covering the groove; the two-dimensional material layer includes a conductive two-dimensional material; Respectively disposing a first electrode and a second electrode at two ends of the two-dimensional material layer relative to the groove, both the first electrode and the second electrode are in contact with the substrate, and the shortest distance between the first electrode and the central axis of the groove is different from the shortest distance between the second electrode and the central axis of the groove, to obtain a flexoelectricity-regulated field-effect transistor.

Images