Organic tunneling field effect transistor and method of making the same

Abstract

The application provides an organic tunneling field effect transistor and a preparation method thereof, and relates to the technical field of the organic tunneling field effect transistor. The application inserts a molecular insertion layer between an organic semiconductor single crystal thin film layer and a metal oxide layer, can effectively prevent the penetration and damage of the metal oxide layer to the organic semiconductor single crystal thin film layer, avoids the diffusion of the first motor layer clusters into the organic semiconductor single crystal thin film layer to cause a large number of defects, strain and disordered states, weakens the Fermi level pinning effect of the organic semiconductor single crystal thin film layer and the metal oxide layer, reduces the tunneling barrier, improves the transmission probability of BTBT, and thus makes the subthreshold swing of the organic tunneling field effect transistor obviously less than 60 mV dec ‑1 , which indicates that the device can be turned on at a very fast speed.

Description

Technical Field

[0001] This invention relates to the technical field of organic tunneling field-effect transistors, and in particular to an organic tunneling field-effect transistor and its fabrication method. Background Technology

[0002] Organic thin-film transistors (TFTs) are fundamental building blocks for organic electronic and optoelectronic devices in integrated circuits. To date, the charge carrier mobility of TFTs has exceeded 10⁻⁶ cm⁻¹. 2 V -1 s -1 Comparable to commercially available amorphous silicon field-effect transistors, organic thin-film transistors (OSTs) achieve the electrical performance required for practical device applications. Using organic semiconductors as the conductive channel layer, OSTs offer several competitive advantages, including low cost, solution processability, and excellent intrinsic flexibility. Therefore, compared to widely used silicon transistors, OSTs hold great potential for flexible wearable electronics, accelerating the development of human-computer interaction, health monitoring, and the Internet of Things (IoT).

[0003] Besides carrier mobility, high signal amplification efficiency and low power consumption are also key factors for meeting these practical applications. Therefore, fabricating organic thin-film transistors (TFTs) with both high signal amplification efficiency and low power consumption is an important prerequisite for real-world device applications. Reducing the subthreshold swing (SS) of the transistor is a necessary prerequisite for achieving high signal amplification efficiency at low power. It has been reported that tunneling field-effect transistors (TEFETs) are a type of transistor that can overcome the theoretical limit of hot electron injection (SS < 60 mV / dec). -1 Unlike the hot carrier injection mechanism of traditional transistors, tunneling transistors primarily employ a cold charge injection mechanism called band-to-band tunneling (BTBT), where charge carriers transfer from the valence band to the conduction band or vice versa. Tunneling transistors have been successfully implemented on various inorganic semiconductor materials, including silicon, carbon nanotubes, and two-dimensional materials.

[0004] In traditional tunneling transistors (TTPTs), the interband BBT transport path is established by designing a heterojunction. This heterojunction uses either a heavily doped N+ type semiconductor as the source electrode and a P-type semiconductor as the channel, or a heavily doped P+ type semiconductor as the source electrode and an N-type semiconductor as the channel. Since heavy doping of organic semiconductors with P-type or N-type semiconductors remains a recognized challenge, establishing an all-organic heterojunction for BBT transport presents a key technical hurdle. Using heavily doped inorganic materials as the source metal electrode to establish an inorganic source-organic channel heterojunction may be an alternative. However, traditional inorganic-organic interfaces are often plagued by severe Fermi level pinning, resulting in a high energy barrier at the tunnel junction and reducing the BBT transport probability. This is because several types of interactions are difficult to avoid at the interface of two different materials. First, due to the high deposition temperature of inorganic materials, high-energy inorganic atoms or clusters can bombard organic semiconductors, generating high heat and disrupting molecular packing, creating numerous defects on the semiconductor surface. Second, the diffusion of atoms or clusters can induce significant strain in the crystal lattice, altering the band structure of the organic semiconductor. Third, the extended wavefunctions from heavily doped inorganic materials severely disrupt the environment of organic semiconductors. Due to the significant differences in carrier concentration between them, some molecular energy levels may be split, forming new defect state energy levels in the band gap of organic semiconductors. Therefore, although inorganic-organic heterojunctions are a promising approach, successfully realizing tunneling transistors using organic semiconductors as channel materials remains a significant challenge. Summary of the Invention

[0005] The first aspect of the present invention is to provide an organic tunneling field-effect transistor that solves the technical problem of low BTBT transmission probability in the prior art.

[0006] A second aspect of the present invention is to provide a method for fabricating an organic tunneling field-effect transistor.

[0007] According to a first aspect of the present invention, the present invention provides an organic tunneling field-effect transistor, comprising, from bottom to top, a gate layer, an oxide layer, a polymer layer, an organic semiconductor single crystal thin film layer, a molecular insertion layer and an electrode layer, wherein the electrode layer has, from bottom to top, a metal oxide layer and a metal layer.

[0008] The material of the organic semiconductor single crystal thin film layer is a P-type organic small molecule semiconductor material, the material of the molecular insertion layer is an N-type organic small molecule semiconductor material with an ionization energy higher than that of the P-type organic small molecule semiconductor material, and the material of the metal oxide layer is a heavily doped N-type semiconductor material with a high work function.

[0009] Optionally, the thickness of the molecular insertion layer is any value in the range of 4 nm to 6 nm;

[0010] The thickness of the metal oxide layer is any value in the range of 4 nm to 6 nm.

[0011] Optionally, the material of the organic semiconductor single-crystal thin film layer includes C8-BTBT, C... 10 -BTBT, C 10 -DNTT, C8-DNBDT-NW, Ph-BTBT-C8, 2,8-difluoro-5,11-bis(triethylsilylethynyl)anthrathiophene, 6,13-bis(triisopropylsilylethynyl)pentabenzene;

[0012] The material of the metal oxide layer includes any one of molybdenum trioxide, chromium trioxide, vanadium pentoxide, and tungsten trioxide;

[0013] The material of the molecular insertion layer includes any one of BPE-PTCDI, C8-PTCDI, and C60.

[0014] According to a second aspect of the present invention, the present invention provides a method for fabricating an organic field tunneling transistor as described above, comprising the following steps:

[0015] A polymer layer is formed on an N-type heavily doped SiO2 / Si substrate to obtain the substrate.

[0016] A solution containing the P-type organic small molecule semiconductor material is coated onto the substrate to form an organic semiconductor single crystal thin film on the substrate.

[0017] A metal mask is fixed on the surface of the organic semiconductor single crystal thin film;

[0018] The N-type organic small molecule semiconductor material with a higher ionization energy than the P-type organic small molecule semiconductor material is deposited by thermal evaporation to prepare the molecular insertion layer on the organic semiconductor single crystal thin film and to create a conductive channel;

[0019] The heavily doped N-type semiconductor material with a high work function is deposited by thermal evaporation to form the metal oxide layer on the molecular insertion layer;

[0020] Silver is deposited by thermal evaporation to form the metal layer on the metal oxide layer.

[0021] Optionally, the step of coating the substrate with a solution of the P-type organic small molecule semiconductor material to form the organic semiconductor single crystal thin film on the substrate specifically includes the following steps:

[0022] The substrate is placed on the substrate of the coating machine, such that there is a preset distance between the substrate and the scraper located above the substrate, and the scraper and the substrate are at a preset angle.

[0023] A solution containing the P-type organic small molecule semiconductor material is applied into the gap between the substrate and the scraper;

[0024] The scraper is controlled to move at a preset speed so that the meniscus formed near the gap crystallizes rapidly under the guidance of the scraper, thereby forming the organic semiconductor single crystal thin film.

[0025] Optionally, the preset spacing is any value in the range of 80 μm-120 μm;

[0026] The preset angle is any value within the range of 15°-50°.

[0027] Optionally, the preset speed is in the range of 230 μm·s. -1 -270 μm·s -1 Any value in;

[0028] The volume of the solution containing the p-type organic small molecule semiconductor material is any value between 8 μL and 12 μL.

[0029] Optionally, the step of preparing a polymer layer on an N-type heavily doped SiO2 / Si substrate to obtain a substrate specifically includes the following steps:

[0030] The polymer layer material is spin-coated onto the N-type heavily doped SiO2 / Si substrate for a first preset time at a preset rotation speed;

[0031] Crosslinking treatment is performed by ultraviolet exposure for a second preset duration, the second preset duration being longer than the first preset duration;

[0032] The substrate is heated at a preset temperature for a third preset time to remove residual solvent, thereby obtaining the substrate. The third preset time is longer than the second preset time.

[0033] Optionally, the preset rotational speed is any value within the range of 2200 rpm to 2700 rpm;

[0034] The first preset duration is any value within the range of 15s-40s;

[0035] The second preset duration is any value within the range of 50min-70min.

[0036] Optionally, the preset temperature is any value within the range of 90℃-110℃;

[0037] The third preset duration is any value within the range of 1.5 h to 2.5 h.

[0038] The organic tunneling field-effect transistor (OTPT) of this invention comprises, from bottom to top, a gate layer, an oxide layer, a polymer layer, an organic semiconductor single-crystal thin film layer, a molecular insertion layer, and an electrode layer. The electrode layer has, from bottom to top, a metal oxide layer and a metal layer. The organic semiconductor single-crystal thin film layer is made of a p-type organic small-molecule semiconductor material, the molecular insertion layer is made of an n-type organic small-molecule semiconductor material with an ionization energy higher than that of the p-type organic small-molecule semiconductor material, and the metal oxide layer is made of a heavily doped n-type semiconductor material with a high work function. This technical solution inserts a molecular insertion layer between the organic semiconductor single-crystal thin film layer and the metal oxide layer, which effectively prevents the metal oxide layer from penetrating and damaging the organic semiconductor single-crystal thin film layer, avoids the diffusion of first-electrode layer clusters into the organic semiconductor single-crystal thin film layer leading to a large number of defects, strains, and disordered states, weakens the Fermi level pinning effect between the organic semiconductor single-crystal thin film layer and the metal oxide layer, reduces the tunneling barrier, and improves the transmission probability of the BTBT. Therefore, the subthreshold swing of the organic tunneling field-effect transistor is significantly less than 60 mV dec. -1 This indicates that the device can be turned on at an extremely fast speed.

[0039] The above and other objects, advantages and features of the present invention will become more apparent to those skilled in the art from the following detailed description of specific embodiments of the invention in conjunction with the accompanying drawings. Attached Figure Description

[0040] The following sections will describe some specific embodiments of the invention in detail by way of example and not limitation, with reference to the accompanying drawings. The same reference numerals in the drawings denote the same or similar parts or portions. Those skilled in the art should understand that these drawings are not necessarily drawn to scale. In the drawings:

[0041] Figure 1 This is a schematic structural diagram of an organic tunneling field-effect transistor according to an embodiment of the present invention;

[0042] Figure 2 This is a schematic flowchart of a method for fabricating an organic tunneling field-effect transistor according to an embodiment of the present invention;

[0043] Figure 3 This is a schematic flowchart of a method for fabricating an organic tunneling field-effect transistor according to another embodiment of the present invention;

[0044] Figure 4 (a) is a polarization optical microscope image of an organic tunneling field-effect transistor with a molecular insertion layer after the electrode layer and the molecular insertion layer have been removed;

[0045] Figure 4 (b) is a schematic cross-sectional view of an organic tunneling field-effect transistor without a molecular insertion layer;

[0046] Figure 4 (c) is a polarization optical microscope image of an organic tunneling field-effect transistor without a molecular insertion layer after the electrode layer has been removed;

[0047] Figure 5 (a) is a cross-sectional transmission electron microscope image and a dark-field scanning transmission image of an organic tunneling field-effect transistor with a molecular insertion layer;

[0048] Figure 5 (b) are cross-sectional transmission electron microscope images and dark-field scanning transmission images of organic tunneling field-effect transistors without molecular insertion layers;

[0049] Figure 6 It is to fix different drain voltages V at room temperature DS Drain current -I DS With gate voltage V GS Relationship diagram;

[0050] Figure 7 It is the drain current -I DS The square root of the gate voltage V GS Relationship diagram;

[0051] Figure 8 It is the gate voltage V GS Output characteristic curves of organic tunneling field-effect transistors located between 0.3V and -1V;

[0052] Figure 9 The subthreshold swing SS and drain current -I of organic tunneling field-effect transistors with and without molecular intercalation layers are compared. DS The functional relationship graph;

[0053] Figure 10 yes Figure 9 Enlarged schematic diagram of the part;

[0054] Figure 11 The drain voltage V is within the temperature range of 195K to 300K. DS =-1V drain current -I DS With gate voltage V GS Characteristic curves;

[0055] Figure 12 The graphs show the subthreshold swing SS of organic tunneling field-effect transistors (OTFETs) with and without molecular intercalation layers as a function of temperature.

[0056] Figure 13 This is a circuit diagram of an amplifier composed of a current source and an organic tunneling field-effect transistor.

[0057] Figure 14 It is the power supply voltage V dd The amplifier's output voltage V at 2V out and gain as a function of input voltage V in Changing electrical test diagram;

[0058] Figure 15 The amplifier's power consumption varies with the input voltage V. in A diagram showing the changing relationships.

[0059] Figure label:

[0060] 10-Gate layer, 21-Oxide layer, 22-Polymer layer, 20-Insulating layer, 30-Organic semiconductor single crystal thin film layer, 40-Molecular insertion layer, 50-Electrode layer, 51-Metal oxide layer, 52-Metal layer. Detailed Implementation

[0061] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0062] In recent years, many inorganic tunneling transistors based on silicon, carbon nanotubes, and two-dimensional materials have been reported, and these methods have successfully achieved voltage reduction rates below 60 mV / dec. -1 The subthreshold swing significantly reduces the operating voltage and power consumption of the device. However, due to their inherent rigidity, inorganic tunneling transistors cannot be bent, making them difficult to apply to flexible wearable electronic devices. The field of organic tunneling field-effect transistors has been pursuing low SS (stable voltage drop), but the severe Fermi level pinning problem at the gold-semiconductor interface has hindered the breakthrough of SS to 60 mV / dec. -1 .

[0063] Figure 1 This is a schematic structural diagram of an organic tunneling field-effect transistor according to an embodiment of the present invention. Figure 1As shown, in this embodiment, the organic tunneling field-effect transistor includes, from bottom to top, a gate layer, an oxide layer, a polymer layer, an organic semiconductor single-crystal thin film layer, a molecular insertion layer, and an electrode layer. The electrode layer has a metal oxide layer and a metal layer formed from bottom to top. The organic semiconductor single-crystal thin film layer is made of a P-type organic small-molecule semiconductor material, the molecular insertion layer is made of an N-type organic small-molecule semiconductor material with an ionization energy higher than that of the P-type organic small-molecule semiconductor material, and the metal oxide layer is made of a heavily doped N-type semiconductor material with a high work function, the work function of which is greater than 5.4 eV. Here, the gate layer is made of N-type heavily doped silicon. The oxide layer and the polymer layer together constitute an insulating layer, and together provide dielectric capacitance. The oxide layer is made of silicon dioxide, and the metal layer is made of silver.

[0064] This embodiment inserts a molecular intercalation layer between the organic semiconductor single-crystal thin film layer and the metal oxide layer. This effectively prevents the metal oxide layer from penetrating and damaging the organic semiconductor single-crystal thin film layer, avoiding the diffusion of the first motor layer clusters into the organic semiconductor single-crystal thin film layer, which would lead to a large number of defects, strain, and disordered states. It also weakens the Fermi level pinning effect between the organic semiconductor single-crystal thin film layer and the metal oxide layer and reduces the tunneling barrier, thereby increasing the transmission probability of the BTBT. This results in the subthreshold swing of the organic tunneling field-effect transistor being significantly less than 60 mV dec. -1 This indicates that the device can be turned on at an extremely fast speed.

[0065] The SS of low-voltage organic tunneling field-effect transistors is limited by thermoelectric potential and cannot exceed 60 mV dec. -1 Tunneling transistors based on the band-to-band tunneling mechanism hold promise for achieving this goal, but the severe Fermi level pinning effect between organic and inorganic heterojunctions hinders its realization. This embodiment mainly invents a method for decoupling a molecular insertion layer, which weakens the Fermi level pinning effect at the interface between the P-type organic semiconductor single-crystal thin film and the N-type heavily doped oxide and reduces the tunneling barrier, successfully realizing an organic tunneling field-effect transistor based on an organic semiconductor active layer.

[0066] In this embodiment, the thickness of the molecular insertion layer is any value within the range of 4nm-6nm, and the thickness of the metal oxide layer is any value within the range of 4nm-6nm. For example, the thickness of the molecular insertion layer can be 4nm, 4.5nm, 5nm, 5.5nm, and 6nm. The thickness of the metal oxide layer can be 4nm, 4.5nm, 5nm, 5.5nm, and 6nm. When the thickness of the molecular insertion layer is less than 4nm, the molecular insertion layer cannot form a dense film on the surface of the organic semiconductor single crystal thin film layer, thus losing the interface decoupling effect, and the device exhibits a large subthreshold swing. When the thickness of the molecular insertion layer is greater than 6nm, the probability of charge carriers tunneling from the metal oxide layer to the conductive channel of the organic semiconductor single crystal thin film layer in the vertical direction is very low, which will cause the on-state current of the device to drop sharply. Therefore, when the thickness of the molecular insertion layer is within the range of 4nm-6nm, a dense film can be formed on the surface of the organic semiconductor single crystal thin film layer to ensure the interface decoupling effect, while also increasing the probability of the metal oxide layer tunneling to the conductive channel of the organic semiconductor single crystal thin film layer.

[0067] In this embodiment, the material of the organic semiconductor single-crystal thin film layer includes C n -BTBT, C n -DNTT、C n -DNBDT-NW, Ph-BTBT-C n The material is selected from any one of the following: 2,8-difluoro-5,11-bis(triethylsilylethynyl)anthrathiophene (Dif-TES-ADT) and 6,13-bis(triisopropylsilylethynyl)pentacene (Tips-pentacene). Here, the p-type organic small molecule semiconductor material is composed of long-range ordered arrangements of organic small molecules, with the entire crystal consisting of a single spatial lattice in three dimensions. The material used is an organic small molecule material that is easy to grow into high-crystallinity organic single crystals. Only a few special molecules in organic small molecule materials can be used to prepare organic single crystals; other molecules are mostly used to prepare polycrystalline or amorphous materials with high defect state density and multiple grain boundaries. Among them, C... n -BTBT can be C8-BTBT and C 10 -BTBT, C n -DNTT can be C 10 -DNTT, C n -DNBDT-NW can be C8-DNBDT-NW, Ph-BTBT-C n It can be Ph-BTBT-C8.

[0068] In this embodiment, the material of the metal oxide layer includes any one of molybdenum trioxide, chromium trioxide, vanadium pentoxide, and tungsten trioxide, namely MoO3, GrO3, V2O5, and WO3. In this device structure, the metal oxide layer and the metal layer together serve as the electrodes of the field-effect transistor.

[0069] In this embodiment, the material of the molecular insertion layer includes any one of BPE-PTCDI, C8-PTCDI, and C60. Here, the material used for the molecular insertion layer needs to have an ionization energy higher than that of p-type organic small molecule semiconductor materials, and also needs to be able to undergo thermal electroplating deposition and form a dense film on the organic semiconductor single crystal thin film layer.

[0070] Figure 2 This is a schematic flowchart illustrating a method for fabricating an organic tunneling field-effect transistor according to an embodiment of the present invention. Figure 2 As shown, in a specific embodiment, the fabrication method of the organic tunneling field-effect transistor includes the following steps:

[0071] Step S100: A polymer layer is formed on an N-type heavily doped SiO2 / Si substrate to obtain a substrate;

[0072] Step S200: A solution containing a P-type organic small molecule semiconductor material is coated onto a substrate to form an organic semiconductor single crystal thin film on the substrate.

[0073] Step S300: Fix a metal mask on the surface of the organic semiconductor single crystal thin film;

[0074] In step S400, an N-type organic small molecule semiconductor material with a higher ionization energy than the P-type organic small molecule semiconductor material is deposited by thermal evaporation to prepare a molecular insertion layer on the organic semiconductor single crystal thin film and to create a conductive channel.

[0075] Step S500: A heavily doped N-type semiconductor material with a high work function is deposited by thermal evaporation to form a metal oxide layer on the molecular insertion layer.

[0076] In step S600, silver is deposited by thermal evaporation to form a metal layer on the metal oxide layer.

[0077] Before step S100, the N-type heavily doped silicon wafer with a 300 nm oxide layer on its surface is first immersed in concentrated sulfuric acid for 12 h, and then ultrasonically treated in acetone, ethanol and deionized water for 15 min each, followed by drying in a nitrogen stream. After ultraviolet ozone treatment for 30 min, the polymer layer is then prepared.

[0078] In step S300, the device with an organic semiconductor single crystal thin film is transferred to a thermal evaporation apparatus and fixed on a special sample holder for evaporation. The metal mask has a hollow pattern and defines the length and width of the conductive channel of the organic tunneling field-effect transistor, which are 200 μm and 500 μm, respectively.

[0079] In step S400, the vacuum chamber in the thermal evaporation process is evacuated to 5 × 10⁻⁶. -5 After applying a basic pressure of Pa, vapor deposition is performed, with the molecular insertion layer deposited at 0.1 Å s. -1 The deposition rate is high enough to deposit on organic semiconductor single-crystal thin films.

[0080] In step S500, at 0.1 Å s -1 The deposition rate is such that a metal oxide layer with a thickness of about 5 nm is thermally evaporated on the molecular insertion layer.

[0081] In step S600, at 0.4 Å s -1 The deposition rate is such that Ag with a thickness of about 40 nm is thermally evaporated onto the metal oxide layer.

[0082] Figure 3 This is a schematic flowchart illustrating a method for fabricating an organic tunneling field-effect transistor according to another embodiment of the present invention. Figure 3 As shown, in this embodiment, step S100 specifically includes the following steps:

[0083] Step S110: Spin-coating a polymer layer material onto an N-type heavily doped SiO2 / Si substrate at a preset rotation speed for a first preset time. Here, the polymer layer material is a low-temperature crosslinkable poly(vinyl cinnamate) (PVC). n );

[0084] Step S120: Crosslinking treatment is performed by ultraviolet exposure for a second preset time, which is longer than the first preset time. Here, ultraviolet exposure is performed by an ultraviolet curing machine (UV Curer KW-4AC).

[0085] Step S130: Heat at a preset temperature for a third preset time to remove residual solvent, thereby obtaining a substrate. The third preset time is longer than the second preset time.

[0086] In this embodiment, the preset speed is any value within the range of 2200rpm-2700rpm, such as 2200rpm, 2300rpm, 2400rpm, 2500rpm, 2600rpm, and 2700rpm. In a preferred embodiment, the preset speed is 2500rpm.

[0087] In this embodiment, the first preset duration is any value within the range of 15s-40s, for example, it can be 15s, 20s, 25s, 30s, 35s, and 40s. In a preferred embodiment, the first preset duration is 30s.

[0088] In this embodiment, the second preset duration is any value within the range of 50 min to 70 min, for example, it can be 50 min, 55 min, 60 min, 65 min, and 70 min. In a preferred embodiment, the second preset duration is 60 min.

[0089] In this embodiment, the preset temperature is any value within the range of 90℃-110℃, for example, 90℃, 100℃, and 110℃. In a preferred embodiment, the preset temperature is 100℃. The third preset duration is any value within the range of 1.5h-2.5h, for example, 1.5h, 2h, and 2.5h.

[0090] In this embodiment, step S200 specifically includes the following steps:

[0091] Step S210: Place the substrate on the substrate of the squeegee, such that there is a preset distance between the substrate and the squeegee located above the substrate, and the squeegee and the substrate are at a preset angle.

[0092] Step S220: Apply a solution containing a P-type organic small molecule semiconductor material to the gap between the substrate and the scraper;

[0093] In step S230, the scraper is controlled to move at a preset speed so that the meniscus formed near the gap crystallizes rapidly under the guidance of the scraper, thereby forming an organic semiconductor single crystal thin film. Subsequent characterization of the organic single crystal thin film morphology and device uses typical C8-BTBT and BPE-PTCDI materials.

[0094] In step S200, an organic semiconductor single crystal thin film is formed at room temperature, and the doctor blade is treated with octadecyltrichlorosilane (OTS) before use.

[0095] In this embodiment, the preset spacing is any value within the range of 80μm-120μm, for example, 80μm, 90μm, 100μm, 110μm, and 110μm. The preset angle is any value within the range of 15°-50°, for example, 15°, 20°, 25°, 30°, 35°, 40°, 45°, and 50°. The preset speed is within the range of 230 μm·s. -1 -270 μm·s -1 Any value in it, for example, can be 230 μm·s -1 240μm·s -1 250 μm·s-1 260 μm·s -1 and 270 μm·s -1 .

[0096] In this embodiment, the volume of the solution containing the P-type organic small molecule semiconductor material is any value between 8 μL and 12 μL, for example, 8 μL, 9 μL, 10 μL, 11 μL and 12 μL.

[0097] In emerging application areas such as wearable technology, electronic skin, and bioelectronics, the pursuit of organic transistors with high signal amplification efficiency and low power consumption has become extremely prominent. For a long time, efforts have been made to develop innovative organic transistor technologies, but further improvements in signal amplification efficiency at low power consumption have been limited by the thermoelectric potential of 60 mVdec. -1 The SS (Self-Discharge) is hindered. Therefore, this embodiment presents a case of a subthermal electron organic tunneling field-effect transistor (OTFET) by inventing a decoupling method for interface interactions. A high-ionization-energy molecular insertion layer is inserted at the interface of the metal-oxide and organic semiconductor heterojunction, minimizing the interfacial gap states and achieving a record-low SS of 35.2 ± 7.6 mV dec. -1 It achieves a record-high signal amplification efficiency of 68.4 ± 14.7 SA with ultra-low power consumption. -1 .

[0098] Figure 4 (a) is a polarization optical microscope image of an organic tunneling field-effect transistor with a molecular insertion layer after the electrode layer and the molecular insertion layer have been removed. Figure 4 (b) is a schematic cross-sectional view of an organic tunneling field-effect transistor without a molecular insertion layer. Figure 4 (c) is a polarization optical microscope image of an organic tunneling field-effect transistor without a molecular insertion layer after the electrode layer has been removed. Figure 4 (a) Figure 4 (b) and Figure 4 As shown in (c), the molecular intercalation layer effectively prevents MoO3 from penetrating and damaging the organic semiconductor single-crystal thin film. This embodiment mechanically peels the deposited metal electrode, MoO3, and molecular intercalation layer from the surface of the organic single-crystal thin film, as... Figure 4 As shown in (a), the area enclosed by the white dashed line originally covered the electrode film. After the electrode was peeled off, the underlying organic semiconductor single-crystal film retained its original disk-like morphology without any obvious damage. Conversely, without the molecular intercalation layer passivating the gold semi-contact interface, such as Figure 4As shown in (b), the thermally deposited MoO3 clusters bombard the organic semiconductor single-crystal film with high energy, causing surface crystal defects. Furthermore, the MoO3 clusters diffuse into the crystal lattice, resulting in numerous defects, strains, and disordered states. The deposited MoO3 clusters typically form a strong interaction with the underlying organic semiconductor single-crystal film and adhere tightly to it. Therefore, when the deposited metal electrode and MoO3 are mechanically peeled off from the surface of the organic semiconductor single-crystal film, the underlying organic semiconductor single-crystal film is also simultaneously damaged, such as... Figure 4 As shown in (c), the area within the white dashed box originally had a deposition size of 200 × 300 μm. 2 The MoO3 electrode in this region is where the organic semiconductor single-crystal film disappears as the MoO3 is peeled off.

[0099] Figure 5 (a) is a cross-sectional transmission electron microscope image and a dark-field scanning transmission electron image of an organic tunneling field-effect transistor with a molecular insertion layer. Figure 5 (b) shows cross-sectional transmission electron microscopy (TEM) images and dark-field scanning transmission electron microscopy (DSS) images of an organic tunneling field-effect transistor without a molecular insertion layer. For example... Figure 5 (a) and Figure 5 As shown in (b), the cross-sectional transmission electron microscopy (TEM) image further demonstrates that the molecular intercalation layer effectively passivates the metal-semiconductor interface. In this embodiment, a 100 nm thick organic semiconductor single-crystal thin film / molecular intercalation layer / MoO3 cross-sectional sheet was first cut using focused ion beam technology, and then observed using a cross-sectional transmission electron microscope. Figure 5 As shown in (a), with the protection of the molecular intercalation layer, a clear material interface is formed due to the effective separation of the organic semiconductor single-crystal thin film layer and the MoO3 layer. MoO3 is completely not observed in the organic semiconductor single-crystal thin film layer, indicating that almost no structural disorder or defects are generated. Conversely, as... Figure 5 As shown in (b), the cross-sectional transmission electron microscopy results of directly deposited MoO3 onto the surface of an organic semiconductor single-crystal thin film without the protection of a molecular intercalation layer reveal a clear boundary between the organic semiconductor single-crystal thin film and the organic insulating layer due to the increased contrast caused by the uniform penetration of MoO3. This visually demonstrates the fact that MoO3 has penetrated into the organic semiconductor single-crystal thin film. The penetration of MoO3 will cause lattice distortion in the organic single crystal and generate a large number of interfacial gap states at the metal-semiconductor contact interface, leading to a severe Fermi level pinning effect, making it difficult to control the surface potential of the organic semiconductor single-crystal thin film by the gate voltage.

[0100] Figure 6 It is to fix different drain voltages V at room temperature DS Drain current -I DS With gate voltage V GS Relationship diagram, Figure 7It is the drain current -I DS The square root of the gate voltage V GS Relationship diagram, Figure 8 It is the gate voltage V GS Output characteristic curves of organic tunneling field-effect transistors (TEFETs) located between 0.3V and -1V. (Example:) Figures 6 to 8 As shown, Figure 6 The typical transfer characteristic curves of the organic tunneling field-effect transistor fabricated in this embodiment are shown, firstly at different V values ​​from -1V to -1.5V. DS The down-transfer curve showed almost no change, indicating that the device current had already reached saturation at an extremely low voltage of -1V. Secondly, Figure 6 The inset shows a magnified transfer curve in the subthreshold region compared to the theoretical limit of thermionic emission, SS (60 mV dec). -1 A direct comparison shows that the SS of the organic tunneling field-effect transistor is significantly less than 60 mV dec. -1 This indicates that the device can be turned on at an extremely fast speed. Finally, because the device has only a small number of overcoming thermionic carriers in the off-state, the off-state current is extremely low (in 10). -15 A and 10 -14 Between A and B, as the device's BBT-BT transport is activated, a large number of tunneling carriers are generated, resulting in an extremely high on-state current (8 × 10⁻⁶ A). -8 A), the device switching ratio exceeds 7 orders of magnitude. Figure 7 The intersection of the reverse extension of the straight line segment of the curve with the x-axis is the threshold voltage of the organic tunneling field-effect transistor, which exhibits a threshold voltage close to 0 V (0.13V), which is far superior to the threshold voltage of traditional organic transistors that are often tens of volts. Figure 8 In the middle, the gate voltage V GS The test range is 0.3V to -1V, first the drain current -I DS At the drain voltage V DS At lower levels, the voltage exhibits a rapidly rising linear trend, indicating a relatively small energy barrier at the metal-semiconductor interface. Secondly, different gate voltages V... GS Drain current -I DS The devices reached saturation after -1V, indicating that they can meet the low-voltage safety requirements of flexible wearable electronic devices.

[0101] Figure 9 The subthreshold swing SS and drain current -I of organic field-effect transistors with molecular intercalation layers and those without molecular intercalation layers are compared. DS The function relationship graph, Figure 10 yes Figure 9 Enlarged schematic diagram of the part. For example... Figure 9 and Figure 10As shown, to more intuitively demonstrate the advantages of the organic tunneling field-effect transistor fabricated in this embodiment, it is compared with a conventional organic tunneling field-effect transistor. The subthreshold swing SS and drain current -I are extracted from the transfer characteristic curve. DS Relationships, such as Figure 9 As shown, organic tunneling field-effect transistors (OTFETs) with high-ionization-energy molecular insertion layers exhibit a significantly lower subthreshold swing (SS) across the entire current range than conventional devices. This indicates that OFETs can achieve current boosts of several orders of magnitude at lower voltages, functioning as low-voltage control devices. Figure 10 As shown, the subthreshold swing SS is less than 60 mV dec -1 The minimum point subthreshold swing (SS) can reach at least 35.5 mV dec. -1 The average SS at different current orders of magnitude was also calculated, one current order of magnitude (10 -15 Up to 10 -14 The average SS of A) is 35.5 mV dec. -1 Two orders of magnitude of current (10 -15 Up to 10 -13 The average SS for A) is 48.8 mV dec. -1 Three orders of magnitude of current (10 -15 Up to 10 -12 The average SS of A) is 53.8 mV dec. -1 Four orders of magnitude of current (10 -15 Up to 10 -11 The average SS of A) is 59.5 mV dec. -1 This aligns with the recommendations in the international semiconductor technology roadmap.

[0102] Figure 11 The drain voltage V is within the temperature range of 195K to 300K. DS =-1V drain current -I DS With gate voltage V GS Characteristic curves Figure 12 This is a graph showing the subthreshold swing (SS) of an organic tunneling field-effect transistor (OTFET) with and without a molecular insertion layer, respectively, as a function of temperature. Figure 11 As shown, the transfer curves of the organic tunneling field-effect transistor fabricated in this embodiment are displayed in an environment ranging from 195 K to 300 K. All curves show almost identical current-to-voltage slopes in the subthreshold region. Figure 11The curves from left to right are 195 K, 210 K, 225 K, 240 K, 255 K, 270 K, 285 K, and 300 K. The minimum SS of the transfer curves in the low-temperature temperature variation experiment was extracted, as shown below. Figure 12 As shown, the SS of the organic tunneling field-effect transistor prepared in this embodiment is almost unaffected by the ambient temperature, while the SS of the conventional organic tunneling field-effect transistor increases with increasing temperature. This directly proves that the carrier transport mechanism of the organic tunneling field-effect transistor is BTBT transport.

[0103] Figure 13 This is a circuit diagram of an amplifier composed of a current source and an organic tunneling field-effect transistor. Figure 14 It is the power supply voltage V dd The amplifier's output voltage V at 2V out and gain as a function of input voltage V in Changing electrical test diagrams Figure 15 The amplifier's power consumption varies with the input voltage V. in A diagram showing the changing relationships. (Example) Figure 13 As shown, the amplifier consists of two organic tunneling field-effect transistors (OTFETs). The OFET on the left serves as the driver transistor, with a channel length of 200 μm. The gate and drain of the OFET on the right are connected, and the device always operates in the off state, acting as a constant current source. To match the current value of the constant current source with the subthreshold current of the OFET, this embodiment increases the off-state current of the transistor by shortening its channel length (50 μm). The ultrathin flexible amplifier has a total of four electrodes, corresponding to the input voltage V. in Power supply voltage V dd Output voltage V out And GND, when testing the amplifier's electrical performance separately, the supply voltage V dd With a fixed operating voltage of 2V and the GND electrode grounded, test the output voltage V. out With input voltage V in Changes. For example... Figure 14 As shown, with the input voltage V in When the voltage is increased from 2V to 2.3V, the output voltage V out The voltage decreases from 2V to 0V, and is related to the output voltage V. out The corresponding change in input voltage V in The range is very narrow, which means that if the input voltage V in By applying a very small voltage signal, an amplifier can output a very large voltage signal, thus amplifying the signal. Figure 14 The amplifier gain was further extracted, with a maximum voltage gain of 537 V / V, exhibiting a steep output voltage characteristic. For example... Figure 15 As shown, the ultra-low power consumption at the amplifier's instantaneous shear point is 0.8 nW. Compared to state-of-the-art organic amplifiers, the gain and power consumption based on organic tunneling field-effect transistors are 206% higher and 20% lower, respectively.

[0104] Therefore, those skilled in the art should recognize that although numerous exemplary embodiments of the present invention have been shown and described in detail herein, many other variations or modifications conforming to the principles of the present invention can be directly determined or derived from the disclosure of the present invention without departing from the spirit and scope of the invention. Thus, the scope of the present invention should be understood and construed as covering all such other variations or modifications.

Claims

1. An organic tunneling field-effect transistor, characterized in that, It includes, from bottom to top, a gate layer, an oxide layer, a polymer layer, an organic semiconductor single crystal thin film layer, a molecular insertion layer, and an electrode layer, wherein the electrode layer has a metal oxide layer and a metal layer formed from bottom to top; The material of the organic semiconductor single crystal thin film layer is a P-type organic small molecule semiconductor material, the material of the molecular insertion layer is an N-type organic small molecule semiconductor material with an ionization energy higher than that of the P-type organic small molecule semiconductor material, and the material of the metal oxide layer is a heavily doped N-type semiconductor material with a high work function.

2. The organic tunneling field-effect transistor according to claim 1, characterized in that, The thickness of the molecular insertion layer is any value in the range of 4nm-6nm; The thickness of the metal oxide layer is any value in the range of 4nm-6nm.

3. The organic tunneling field-effect transistor according to claim 2, characterized in that, The organic semiconductor single-crystal thin film layer is made of materials including C8-BTBT, C... 10 -BTBT, C 10 -DNTT, C8-DNBDT-NW, Ph-BTBT-C8, 2,8-difluoro-5,11-bis(triethylsilylethynyl)anthrathiophene, 6,13-bis(triisopropylsilylethynyl)pentabenzene; The material of the metal oxide layer includes any one of molybdenum trioxide, chromium trioxide, vanadium pentoxide, and tungsten trioxide; The material of the molecular insertion layer includes any one of BPE-PTCDI, C8-PTCDI, and C60.

4. A method for fabricating an organic tunneling field-effect transistor as described in any one of claims 1-3, characterized in that, Includes the following steps: A polymer layer is formed on an N-type heavily doped SiO2 / Si substrate to obtain the substrate. A solution containing the P-type organic small molecule semiconductor material is coated onto the substrate to form an organic semiconductor single crystal thin film on the substrate. A metal mask is fixed on the surface of the organic semiconductor single crystal thin film; The N-type organic small molecule semiconductor material with a higher ionization energy than the P-type organic small molecule semiconductor material is deposited by thermal evaporation to prepare the molecular insertion layer on the organic semiconductor single crystal thin film and to create a conductive channel; The heavily doped N-type semiconductor material with a high work function is deposited by thermal evaporation to form the metal oxide layer on the molecular insertion layer; Silver is deposited by thermal evaporation to form the metal layer on the metal oxide layer.

5. The preparation method according to claim 4, characterized in that, The step of coating a solution containing the P-type organic small molecule semiconductor material onto the substrate to form the organic semiconductor single crystal thin film on the substrate specifically includes the following steps: The substrate is placed on the substrate of the coating machine, such that there is a preset distance between the substrate and the scraper located above the substrate, and the scraper and the substrate are at a preset angle. A solution containing the P-type organic small molecule semiconductor material is applied into the gap between the substrate and the scraper; The scraper is controlled to move at a preset speed so that the meniscus formed near the gap crystallizes rapidly under the guidance of the scraper, thereby forming the organic semiconductor single crystal thin film.

6. The preparation method according to claim 5, characterized in that, The preset spacing is any value within the range of 80μm-120μm; The preset angle is any value within the range of 15°-50°.

7. The preparation method according to claim 6, characterized in that, The preset speed is in the range of 230 μm·s. -1 -270μm·s -1 Any value in; The volume of the solution containing the p-type organic small molecule semiconductor material is any value between 8 μL and 12 μL.

8. The preparation method according to claim 5, characterized in that, The step of preparing a polymer layer on an N-type heavily doped SiO2 / Si substrate to obtain a substrate specifically includes the following steps: The polymer layer material is spin-coated onto the N-type heavily doped SiO2 / Si substrate for a first preset time at a preset rotation speed; Crosslinking treatment is performed by ultraviolet exposure for a second preset duration, the second preset duration being longer than the first preset duration; The substrate is heated at a preset temperature for a third preset time to remove residual solvent, thereby obtaining the substrate. The third preset time is longer than the second preset time.

9. The preparation method according to claim 8, characterized in that, The preset speed is any value within the range of 2200rpm-2700rpm; The first preset duration is any value within the range of 15s-40s; The second preset duration is any value within the range of 50min-70min.

10. The preparation method according to claim 9, characterized in that, The preset temperature is any value within the range of 90℃-110℃; The third preset duration is any value within the range of 1.5h-2.5h.

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