Organic electrochemical transistor with nanosphere photoetching 3D channel

Abstract

The utility model relates to an organic electrochemical transistor with a nanosphere photoetching 3D channel, and belongs to the technical field of microelectronic devices. The lowest layer of the organic electrochemical transistor is a substrate layer, an electrode layer is arranged on the substrate layer, and the electrode layer comprises a source electrode, a drain electrode and a gate electrode. An organic semiconductor channel is arranged between the source electrode and the drain electrode; the organic semiconductor layer channel forms a 3D surface structure through a nanosphere photoetching method, the surface structure comprises recesses and protrusions, and an uneven three-dimensional structure shape is formed, so that the specific surface area and the aperture are increased, and the performance of the organic electrochemical transistor is improved. According to the transistor semiconductor channel, a 3D surface structure is formed through a nanosphere photoetching method, so that the specific surface area of the channel is increased, the response speed of a device is improved, meanwhile, the negative influence of perforation on transconductance of the device is avoided, and the detection sensitivity of the sensor is further improved.

Description

Technical Field

[0001] The utility model belongs to the technical field of microelectronic devices and relates to an organic electrochemical transistor with a nanosphere photolithography 3D channel. Background Art

[0002] Organic Electrochemical Transistor (OECT) is a field-effect transistor based on organic materials. It combines organic synthetic chemistry and electronic technology and has unique performance and application potential. The working principle of OECT is to adjust the conductive properties of the organic semiconductor film by controlling the concentration of charged particles in the electrolyte. When the signal voltage on the electrode changes, the ion concentration in the electrolyte will change, thereby affecting the carrier concentration in the semiconductor, causing the conductivity of the device to change. OECT mainly consists of three electrodes (source, drain and gate) and an organic semiconductor film channel. During operation, the three electrodes are completely immersed in the electrolyte, and the charged particles in the electrolyte can penetrate into the organic semiconductor film, changing its conductivity.

[0003] Current characteristics of organic electrochemical transistors include: Ultra-low power consumption: OECTs have an extremely low operating voltage, typically less than 1V, which gives them significant advantages in low-power applications. Ultra-high sensitivity: OECTs can directly sense changes in the concentration of electrons and holes generated by electrochemical reactions, enabling highly sensitive signal detection. Adaptability: In complex organic physical and chemical environments, OECTs can automatically adjust the magnitude and quality of their output signal, achieving higher precision. Biocompatibility: The organic semiconductor materials used in OECTs have excellent biocompatibility, making them suitable for biomedical applications. Their main application areas are as follows: Biomedicine: OECTs can be used in biosensors, neural interface devices, and neuromorphic computing, such as heart monitoring, neural activity monitoring, and blood glucose monitoring. Their excellent biocompatibility and high sensitivity make them ideal for biomedical sensors. Chemical sensing: OECTs can be used to detect compounds, cells, and biomolecules, such as tumor cell activity and tumor markers in blood. Flexible electronics: Due to their excellent mechanical flexibility and stretchability, OECTs have broad application prospects in flexible electronics, wearable devices, and smart sensors. Energy conversion: OECTs also show potential in energy conversion and storage, such as as components of biofuel cells.

[0004] Organic electrochemical transistors (OECTs) convert and amplify chemical signals into significant electrical response signals by regulating the gate interface capacitance with target analytes, which has great advantages in trace analysis. In organic electrochemical transistors, the gate changes the gate / channel capacitance and the doping state of the channel semiconductor material after binding to the target molecule, thereby changing the source / drain current output, causing the migration curve of the device to shift and the output current to change significantly. Thanks to micro-nano processing technology, the size of electrochemical transistors is usually on the micron scale, and their detection systems are easy to miniaturize, integrate, and have low cost. Currently, the optimization of OECTs is mainly based on the following transconductance model:

[0005] g m =(W / L)·d·μ·C*·(V Th –V G ),

[0006] Where W, L, d are the channel width, length and thickness, μ is the carrier mobility, C* is the channel capacitance per unit volume, V Th is the threshold voltage, V G is the gate voltage. The model μ·C*·(V Th –V G ) portion typically depends solely on the semiconductor channel material, but commercially available semiconductor materials are limited. When optimizing (W / L)·d, increasing the W / L ratio by an order of magnitude requires process upgrades, which is costly. However, when optimizing the d value, significant performance improvements often result in a significant increase in response time. Utility Model Content

[0007] In view of this, the purpose of the present invention is to provide an organic electrochemical transistor with a nanosphere lithography 3D channel, which uses micro-nano processing, screen printing, electrochemical deposition and other methods to prepare the source electrode, drain electrode and gate electrode of the OECT. The organic semiconductor channel between the source electrode and the drain electrode is formed into a 3D surface structure by nanosphere lithography, thereby increasing the specific surface area of ​​the channel, improving the device response speed while avoiding the negative impact of perforation on the device transconductance, thereby improving the sensor detection sensitivity.

[0008] In order to achieve the above-mentioned purpose, the present invention provides the following technical solutions:

[0009] An organic electrochemical transistor with a 3D channel formed by nanosphere photolithography is characterized in that: the bottom layer of the organic electrochemical transistor is a substrate layer, above which is an electrode layer, the electrode layer including a source electrode, a drain electrode and a gate electrode; between the source electrode and the drain electrode is an organic semiconductor channel; the organic semiconductor channel is formed into a 3D surface structure by nanosphere photolithography, the surface structure including depressions and protrusions, forming an uneven three-dimensional structure shape, thereby increasing the specific surface area and pore size, and improving the performance of the organic electrochemical transistor.

[0010] Furthermore, the concave shapes of the organic semiconductor channel surface structure include circle, equilateral triangle, and square arrays, and the diameter and side length of the circle, equilateral triangle, and square are 2 μm to 50 μm.

[0011] Furthermore, the intervals between the concave shapes are greater than or equal to the diameter and side length of a circle, an equilateral triangle, or a square; and the thickness of the concave shapes is 30 nm to 300 nm.

[0012] Furthermore, the substrate layer is a silicon wafer or a quartz wafer; the electrode material of the source electrode, drain electrode, and gate electrode is Au, and the bottom layer of the source electrode, drain electrode, and gate electrode is plated with a Cr or Ni metal layer, and the thickness of the Cr or Ni metal layer is 5nm to 30nm.

[0013] Furthermore, the diameter of the gate electrode is 1 mm to 5 mm, and the thickness of the Au layer is 30 nm to 100 nm; the width of the source electrode and the drain electrode is 1 to 5 mm, and the thickness of the Au layer is 30 nm to 100 nm; the spacing between the source electrode and the drain electrode is 10 μm to 200 μm.

[0014] Furthermore, the length of the organic semiconductor channel is 1 mm to 5 mm, the width is 200 μm to 1 mm, and the thickness of the semiconductor film on the organic semiconductor channel is 300 nm to 600 nm; the organic semiconductor channel completely covers the blank space between the source electrode and the drain electrode, and is placed above the source electrode and the drain electrode.

[0015] The beneficial effects of the present invention are:

[0016] This utility model provides an organic electrochemical transistor with a 3D channel patterned by nanosphere lithography. The transistor comprises an organic semiconductor channel between its source and drain electrodes. This semiconductor channel is formed into a 3D surface structure using nanosphere lithography, thereby increasing the channel's specific surface area, improving device response speed while avoiding the negative impact of perforation on device transconductance, thereby enhancing sensor detection sensitivity. Furthermore, the concave-convex ratio, width, and height of the organic semiconductor channel can be modified by adjusting etching parameters. The concave area ratio can be adjusted by adjusting the spacing and size of the concave shapes, and the specific surface area of ​​the organic semiconductor channel can be further adjusted by adjusting the thickness of the concave shapes.

[0017] Other advantages, objectives, and features of the present invention will be described in detail in the following description and, to some extent, will be apparent to those skilled in the art upon examination and study of the following or may be learned from practice of the present invention. The objectives and other advantages of the present invention may be realized and obtained through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention will be described in detail below with reference to the accompanying drawings, in which:

[0019] Figure 1 Schematic diagram of 3D channel organic electrochemical transistor;

[0020] Figure 2 Schematic diagram of the channel side view of a 3D channel organic electrochemical transistor;

[0021] Figure 3 This is an electron microscope image of the channel of an organic electrochemical transistor with a 3D channel patterned by nanosphere lithography. DETAILED DESCRIPTION

[0022] The technical solution of the utility model is described in detail below with reference to the accompanying drawings.

[0023] Figure 1 This is a schematic diagram of a 3D channel organic electrochemical transistor. As shown in the figure, the bottom layer of the organic electrochemical transistor with a nanosphere lithography 3D channel provided by the present invention is a substrate layer, and above the substrate layer is an electrode layer, which includes a source electrode, a drain electrode and a gate electrode; between the source electrode and the drain electrode is an organic semiconductor channel; the organic semiconductor channel is formed into a 3D surface structure by the nanosphere lithography method, and the surface structure includes depressions and protrusions, forming an uneven three-dimensional structural shape, so as to increase the specific surface area and pore size, and improve the performance of the organic electrochemical transistor.

[0024] Figure 2This is a schematic side view of a 3D channel organic electrochemical transistor channel. The recessed shapes of the organic semiconductor channel surface structure include circular, equilateral triangle, and square arrays, with the diameter and side length of the circles, equilateral triangles, and squares ranging from 2μm to 50μm. The spacing of the recessed shapes is greater than or equal to the diameter and side length of the circles, equilateral triangles, and squares; the thickness of the recessed shapes is 30nm to 300nm. In addition, the concave-convex ratio, width, and height of the organic semiconductor channel can be changed by adjusting the etching parameters; the recessed area ratio can be adjusted by adjusting the spacing and size of the recessed shapes, and the specific surface area of ​​the organic semiconductor channel can be further adjusted by adjusting the thickness of the recessed shapes.

[0025] The method for preparing an organic electrochemical transistor with a 3D channel patterned by nanosphere photolithography has the following steps: First, the substrate is cleaned and dried. Second, the source, drain, and gate electrodes are formed on the cleaned and dried substrate. Third, an organic semiconductor channel is coated between the source and drain electrodes. Fourth, a single layer of silica / PS microspheres is self-assembled and tiled on the semiconductor channel. A reactive ion etcher or ICP etcher is used to etch the microspheres and semiconductor channel using gases including, but not limited to, SF6, O2, N2, CF4, and CHF3, either singly or in mixtures. The microspheres are then cleaned using ultrasound or a solvent such as acetone or CHCl2, leaving behind a 3D semiconductor channel. OECT performance testing revealed that under appropriate conditions, the gate improves the OECT's current regulation capability, i.e., transconductance.

[0026] In this embodiment, the substrate layer is a silicon wafer or a quartz wafer; the electrode material of the source electrode, drain electrode, and gate electrode is Au, and the bottom layer of the source electrode, drain electrode, and gate electrode is plated with a Cr or Ni metal layer, and the thickness of the Cr or Ni metal layer is 5nm to 30nm.

[0027] The gate electrode has a diameter of 1mm to 5mm, and the Au layer is 30nm to 100nm thick. The source and drain electrodes have a width of 1mm to 5mm, and the Au layer is 30nm to 100nm thick. The spacing between the source and drain electrodes is 10μm to 200μm. The organic semiconductor channel has a length of 1mm to 5mm and a width of 200μm to 1mm. The thickness of the semiconductor film on the organic semiconductor channel is 300nm to 600nm. The organic semiconductor channel completely covers the space between the source and drain electrodes and overlaps the source and drain electrodes.

[0028] Figure 3 This is an electron microscope image of the channel of an organic electrochemical transistor with a 3D channel formed by nanosphere lithography. It can be seen that the semiconductor channel forms a 3D surface structure through the method of nanosphere lithography, thereby increasing the specific surface area of ​​the channel, improving the device response speed while avoiding the negative impact of perforation on the device transconductance, thereby improving the sensor detection sensitivity.

[0029] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the utility model and are not limiting. Although the utility model is described in detail with reference to the preferred embodiments, ordinary technicians in this field should understand that the technical solution of the utility model can be modified without departing from the purpose and scope of the technical solution, which should be included in the scope of the claims of the utility model.

Claims

1. An organic electrochemical transistor with a nanosphere lithographic 3D channel, characterized in that: The bottom layer of the organic electrochemical transistor is a substrate layer, and above the substrate layer is an electrode layer, which includes a source electrode, a drain electrode, and a gate electrode; between the source electrode and the drain electrode is an organic semiconductor channel; the organic semiconductor channel is formed into a 3D surface structure by a nanosphere lithography method, and the surface structure includes depressions and protrusions, forming an uneven three-dimensional structure shape.

2. The organic electrochemical transistor with a nanosphere lithography 3D channel according to claim 1, characterized in that: The concave shapes of the organic semiconductor channel surface structure include circle, equilateral triangle and square arrays, and the diameter and side length of the circle, equilateral triangle and square are 2 μm to 50 μm.

3. The organic electrochemical transistor with a nanosphere lithography 3D channel according to claim 2, characterized in that: The intervals between the concave shapes are greater than or equal to the diameter and side length of a circle, an equilateral triangle, or a square; and the thickness of the concave shapes is 30 nm to 300 nm.

4. The organic electrochemical transistor with a nanosphere lithography 3D channel according to claim 3, characterized in that: The substrate layer is a silicon wafer or a quartz wafer; the electrode material of the source electrode, drain electrode and gate electrode is Au; the bottom layer of the source electrode, drain electrode and gate electrode is plated with a chromium or nickel metal layer, and the thickness of the chromium or nickel metal layer is 5nm to 30nm.

5. The organic electrochemical transistor with a nanosphere photolithography 3D channel according to claim 4, characterized in that: The diameter of the gate electrode is 1mm to 5mm, and the thickness of the Au layer is 30nm to 100nm; the width of the source electrode and the drain electrode is 1 to 5mm, and the thickness of the Au layer is 30nm to 100nm; the spacing between the source electrode and the drain electrode is 10μm to 200μm.

6. The organic electrochemical transistor with a nanosphere lithography 3D channel according to claim 5, characterized in that: The length of the organic semiconductor channel is 1mm to 5mm, the width is 200μm to 1mm, and the thickness of the semiconductor film on the organic semiconductor channel is 300nm to 600nm; the organic semiconductor channel completely covers the blank space between the source electrode and the drain electrode, and is placed above the source electrode and the drain electrode.

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