Method for growing DAAQ level nanowire array, nanowire array and application thereof

Abstract

The present invention provides a method for growing a DAAQ horizontal nanowire array, the nanowire array and applications thereof. The method includes: annealing an M-plane sapphire substrate to form horizontally arranged parallel nanoscale channels on its surface; subjecting the sapphire substrate to a surface hydrophobic modification treatment so that the contact angle of its surface is greater than 95°; growing DAAQ nanowires on the surface of the sapphire substrate by chemical vapor deposition. The process flow is simplified, safe and easy to operate. The growth and alignment of DAAQ nanowires are achieved in one step. The obtained nanowires have morphological advantages, high crystallinity and exhibit a crystal orientation preferential growth mode, and can be applied to products such as organic field effect transistors, organic light emitting diodes, organic photovoltaic cells or photodetectors.

Description

Technical Field

[0001] The present invention relates to the field of growth of semiconductor nanomaterials, and particularly to a method for growing a DAAQ horizontal nanowire array, the nanowire array and applications thereof. Background Art

[0002] In recent years, the organic small molecule 1,5-diaminoanthraquinone (C 14 H 10 N2O2, abbreviated as DAAQ in English), as a new type of aromatic compound, has attracted extensive interest from researchers due to its hybrid structure of 1,4-benzoquinone and polyaniline backbone. Due to the formation of hydrogen bonds between the N-H and C=O groups on its anthracene ring and the strong π-π conjugation force in the DAAQ molecular structure, compared with other reported organic small molecules, DAAQ has advantages such as good electrochemical performance, better cycle stability, higher electroactivity and a larger voltage window, making it a potential material.

[0003] Highly ordered nanowire arrays are a prerequisite for the large-scale manufacturing, batch testing and efficient research and development of nanowire functional devices (field effect transistors, photovoltaic cells, sensors, etc.). Compared with inorganic semiconductor nanowires, semiconductor nanowires composed of organic molecules have better flexibility and stretchability, unique π-π conjugated bonds and charge carrier transport established according to the molecular stacking orientation. At the same time, the small size effect, quantum size effect, surface effect and macroscopic quantum tunneling effect existing in the nanowires make their physical and chemical properties different from those of conventional materials. Among them, DAAQ nanowires have some unique advantages, such as relatively easy chemical doping, high reactivity and good processability, which make them complementary to inorganic nanowires. Ordered vertical inorganic nanowire arrays have been fabricated and have been shown to be beneficial for many photon and electronic devices. However, there are few reports on the growth of DAAQ nanowires. Currently, the preparation methods of DAAQ nanowires mainly include physical gas transport methods such as low-temperature vacuum sublimation method and vacuum thermal evaporation method.

[0004] (1) Low-temperature vacuum sublimation method

[0005] The low-temperature vacuum sublimation method is a method for preparing or separating pure solid substances by utilizing the phenomenon that substances directly change from solid state to gaseous state under low temperature and high vacuum conditions. The low-temperature vacuum sublimation method can be used to prepare nanomaterials with special structures or properties, such as nanowires, nanorods, nanotubes, etc. The general process is as follows: put the solid substance to be sublimated into a closed container, usually a glass tube or a quartz tube; evacuate the container to a high vacuum state, usually with a pressure below 10-5 torr; heat one end of the container to reach the sublimation temperature of the substance, usually a temperature lower than its melting point. In this way, the substance will change from solid state to gaseous state and diffuse to the other end of the container; cool the other end of the container to a temperature lower than the condensation temperature of the substance. In this way, the gaseous substance will re-condense into solid state and deposit on the substrate at the cooling end; repeat the above steps until the required nanomaterials or pure solid substances are obtained.

[0006] However, the yield of the low-temperature vacuum sublimation method is relatively low because the sublimation rate of the substance is limited by temperature and pressure, and there will be some loss of the substance during the sublimation process. At the same time, the surface properties of the substrate will affect the deposition and crystallization of the substance, so it is necessary to select appropriate substrate materials and surface treatment methods to improve the adhesion and uniformity of the substance. Secondly, the low-temperature vacuum sublimation method can only prepare some specific nanomaterials.

[0007] (2) Vacuum thermal evaporation method

[0008] Similar to the low-temperature vacuum sublimation method, the vacuum thermal evaporation method is a method in high vacuum conditions, heating the raw materials in the evaporation container to make its atoms or molecules evaporate and escape from the surface to form a vapor flow, which is incident on the surface of a solid (referred to as a substrate or wafer), and then re-condenses. This method is also commonly used in the preparation of other nanostructures such as nanowires and nanotubes.

[0009] Because substances are more likely to undergo chemical reactions or decomposition at high temperatures, the loss of the vacuum thermal evaporation method is relatively large. In addition, it may affect the structure and properties of the substance because substances are more likely to be affected by thermal stress or thermal gradient at high temperatures. At the same time, the disadvantages in the low-temperature vacuum sublimation method also exist in the vacuum evaporation method, such as the surface properties of the substrate will affect the deposition and crystallization of the substance, and the efficiency is low.

[0010] However, due to the special structure of the DAAQ, it is sensitive to temperature and pressure changes during synthesis. Currently, the DAAQ nanowires prepared by existing technical methods are mainly quasi-vertical arrays and the orientation is relatively disordered, and there are almost no reports on the preparation method of horizontally oriented DAAQ nanowire arrays. Summary of the Invention

[0011] The present invention aims to solve at least one of the technical problems existing in the above-mentioned prior art. To this end, the present invention proposes a method for growing a high-quality horizontally oriented array of DAAQ nanowires, and the horizontally oriented DAAQ nanowire array grown by this method is compatible with existing micro-nano processing technologies, which is conducive to the large-scale production and on-chip integration of semiconductor micro-nano devices.

[0012] One aspect of the present invention provides a method for growing a horizontally oriented array of DAAQ nanowires, including the following steps:

[0013] Step S1: Anneal the M-plane sapphire substrate to form horizontally arranged parallel nano-channels on its surface;

[0014] Step S2: Perform a surface hydrophobic modification treatment on the sapphire substrate processed in Step S1 to make the contact angle of its surface greater than 95°;

[0015] Step S3: Use chemical vapor deposition to grow DAAQ nanowires on the surface of the sapphire substrate processed in Step S2.

[0016] The inventors found through experiments that the M-plane sapphire substrate generates orderly channels with a single orientation and a "V"-shaped cross-section on the surface through high-temperature annealing, and eliminates the possible defects on the substrate surface. These nano-scale channels are arranged parallel and orderly, providing high-quality patterned channels for PVD growth, imposing a direction limit on material growth, and then combined with hydrophobization treatment, making the substrate more conducive to the directional growth of a horizontally oriented array of DAAQ nanowires. Without an additional growth template, the process flow is simplified. Using PVD to grow a horizontally oriented array of DAAQ nanowires is safe and easy to operate, achieving the growth and alignment of DAAQ nanowires in one step.

[0017] In some embodiments of the present invention, in Step S1, the depth of the nano-channels is 10-25 nm, and the depth distribution is uniform. At this time, it is easier for DAAQ nanowires to be directionally deposited and grown in the channel direction. Here, within the nano-scale range (1-100 nm), the deeper the nano-channels, the better the DAAQ nanowires can be restricted to grow in the channel direction during the growth process, with fewer branches, longer lengths, and a morphology more tending to unbranched single nanowires.

[0018] In some embodiments of the present invention, in Step S1, the annealing treatment temperature is 1600 °C, and the heat preservation is for 10 h, resulting in more uniform channels and fewer lattice defects in the substrate.

[0019] In some embodiments of the present invention, in Step S2, the hydrophobic modification treatment is achieved by immersing the sapphire substrate in an OTMS solution.

[0020] In some embodiments of the present invention, the OTMS solution is an OTMS n-hexane solution with a ratio of 1 μl / 10 ml, and the soaking time is 1-2 h. The hydrophobic layer formed on the substrate surface has better hydrophobic effect and improved stability, and is more suitable for the directional growth of DAAQ nanowire horizontal arrays.

[0021] In some embodiments of the present invention, in step S2, before the hydrophobic modification treatment, there is also a step of cleaning the sapphire substrate. The cleaning is carried out by ultrasonic cleaning with acetone, isopropanol, 95% ethanol, deionized water, and 95% ethanol solution in sequence. The cleaning time for each time is 10 min, the ultrasonic power is 135 W, and after ultrasonic cleaning, it is flushed with nitrogen. The cleaning is cleaner, and the obtained substrate surface is more tightly combined with the subsequent hydrophobic layer.

[0022] In some embodiments of the present invention, step S3 is carried out in a two-temperature-zone tube furnace; 13 mg of DAAQ powder is placed in a quartz boat and placed in the source temperature zone; the sapphire substrate is placed on an 8-mm-high groove plate and placed together in a quartz boat with an inner diameter of 29 mm, and placed in the growth temperature zone; the distance between the DAAQ powder and the substrate is 20 cm; the temperature of the source temperature zone is 230 °C, the temperature of the growth temperature zone is 70 °C, the carrier gas is N2, the volume flow rate is 90 sccm, the pressure is 16 mbar, and the growth time is 100 min. The obtained horizontal nanowire array has good uniformity and consistency.

[0023] Another aspect of the present invention also provides a DAAQ horizontal nanowire array prepared by the method for growing a DAAQ horizontal nanowire array described above.

[0024] In some embodiments of the present invention, the obtained DAAQ nanowires have a length of 60-340 μm, a width of 500 nm-1.35 μm, and a height of 600-700 nm.

[0025] According to still another aspect of the present invention, there is also provided the application of the DAAQ horizontal nanowire array in organic field effect transistors, organic light emitting diodes, organic photovoltaic cells or photodetector products.

[0026] Compared with the methods of the prior art, the present invention performs hydrophobic treatment on the patterned substrate to control the contact angle, making it more conducive to the directional growth of DAAQ nanowire horizontal arrays. Without an additional growth template, the process flow is simplified. Using PVD to grow the DAAQ nanowire horizontal array is safe and easy to operate. The growth and alignment of DAAQ nanowires are achieved in one step. The prepared DAAQ single crystal nanowires have high crystallinity and exhibit a crystal orientation preference growth mode, and can be applied to organic field effect transistors, organic light emitting diodes, organic photovoltaic cells or photodetector products. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 Schematic diagram of the process for growing DAAQ horizontal nanowire arrays according to an embodiment of the present invention;

[0028] Figure 2 Schematic diagram of the device for growing DAAQ nanowires by PVD;

[0029] Figure 3 SEM images of the M-plane sapphire substrate before and after heat treatment according to an embodiment of the present invention;

[0030] Figure 4 AFM image of the M-plane sapphire substrate after heat treatment according to an embodiment of the present invention;

[0031] Figure 5 Water contact angle diagram of the sapphire surface before hydrophobic modification treatment according to an embodiment of the present invention;

[0032] Figure 6 Water contact angle diagram of the sapphire surface after hydrophobic modification treatment according to an embodiment of the present invention;

[0033] Figure 7 Optical microscope image of the DAAQ nanowire array of Comparative Example 1;

[0034] Figure 8 Optical microscope image of the DAAQ nanowire array of Example 1, with the scale bar being 200 μm;

[0035] Figure 9 Optical microscope image of the DAAQ nanowire array of Example 1, with the scale bar being 10 μm;

[0036] Figure 10 SEM image of the DAAQ nanowire array of Example 1;

[0037] Figure 11 AFM image of the DAAQ nanowire array of Example 1;

[0038] Figure 12 Optical microscope image for measuring the length of the DAAQ nanowire array of Example 1;

[0039] Figure 13 Optical microscope image and SEM image for measuring the width of the DAAQ nanowire array of Example 1;

[0040] Figure 14 XRD spectrum of the DAAQ nanowire array of Example 1. Detailed implementation manners

[0041] In the description of the present invention, unless otherwise clearly defined, terms such as heating, cleaning, weighing, etc. should be understood in a broad sense, and those skilled in the art can reasonably determine the specific meanings of the above terms in the present invention in combination with the specific content of the technical solution.

[0042] In the description of the present invention, the descriptions referring to terms such as "some embodiments", "examples", etc. mean that the specific methods and materials 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 methods and materials described can be combined in a suitable manner in any one or more embodiments or examples.

[0043] The present invention provides a method for growing a DAAQ horizontal nanowire array, including the following steps,

[0044] Step S1: Anneal the M-plane sapphire substrate to form horizontally arranged parallel nanoscale channels on its surface;

[0045] Step S2: Perform a surface hydrophobic modification treatment on the sapphire substrate processed in Step S1 to make the contact angle of its surface greater than 95°;

[0046] Step S3: Use chemical vapor deposition to grow a DAAQ horizontal nanowire array on the surface of the sapphire substrate processed in Step S2.

[0047] The nanoscale channels in Step S1 are the prerequisite for the directional growth of nanowires. The inventors found through experiments that only the surface of the annealed M-plane sapphire substrate can spontaneously form horizontally arranged parallel channels with a "V"-shaped cross-section and eliminate the possible defects on the substrate surface. These nanoscale channels, arranged in parallel and orderly, provide high-quality patterned channels for PVD growth, provide a direction limit for material growth, and are the key to the unidirectional growth of the directional DAAQ nanowire horizontal array. Therefore, forming channels on the surface of the M-plane sapphire substrate by high-temperature annealing is one of the key points of the present invention.

[0048] Preferably, the annealing treatment temperature is 1600 °C and the heat preservation time is 10 h, resulting in more uniform channels and fewer lattice defects in the substrate.

[0049] Preferably, the depth of the nanoscale channels is 10 - 25 nm and the depth distribution is uniform. At this time, it is easier to make the DAAQ nanowires directionally deposit and grow in the channel direction. Here, within the nanoscale range (1 - 100 nm), the deeper the nanoscale channels, the better the DAAQ nanowires can be restricted to grow in the channel direction during the growth process, resulting in fewer branches, longer lengths, and a morphology more tending to unbranched single nanowires for the DAAQ nanowires.

[0050] In step S2, the hydrophobic treatment not only effectively reduces the surface energy of the M-plane sapphire channel substrate, reduces the nucleation growth barrier of DAAQ, and is conducive to the nucleation growth of DAAQ nanowires, but also improves the affinity between the M-plane sapphire surface and the DAAQ organic molecular nanowires, thus providing a key basis for the preferential nucleation of DAAQ organic molecules at the channel and their eventual orderly growth along the channel direction.

[0051] Preferably, the hydrophobic modification treatment is achieved by immersing the sapphire substrate in an OTMS solution. Preferably, the OTMS solution is an OTMS n-hexane solution with a ratio of 1 μl / 10 ml, and the immersion time is 1 - 2 h. On the one hand, the contact angle of the substrate surface is greater than 95°, such as 97°, 99°, 100°, 105°, 107°, 109°, 110°, etc., and the hydrophobic layer formed on the substrate surface has a better hydrophobic effect and improved stability, which is more suitable for the directional growth of the DAAQ nanowire horizontal array.

[0052] In some embodiments, before the surface hydrophobic modification treatment of the sapphire substrate processed in step S1, a cleaning step is also included. The sapphire substrate processed in step S1 can be ultrasonically cleaned successively with acetone, isopropanol, 95% ethanol, deionized water, and 95% ethanol solution. The ultrasonic cleaning time for each time is 10 min, and the ultrasonic power is 135 W to remove the impurities attached to the surface of the sapphire substrate due to oil stains. The sapphire substrate after ultrasonic cleaning is flushed with nitrogen to remove the organic solvents and other impurities on its surface. Cleaning can better perform hydrophobic modification, making the modified layer combine tightly with the substrate and the hydrophobic layer more stable.

[0053] Step S3: Grow a DAAQ horizontal nanowire array on the surface of the sapphire substrate processed in step S2 by chemical vapor deposition.

[0054] It is usually carried out in a two-zone tube furnace, which is divided into a source zone and a growth zone. The DAAQ powder is placed in the source zone, and the sapphire substrate is placed in the growth zone. Before growth, the DAAQ powder is placed outside the growth zone. After heating to the set temperature, the rubrene powder is then pushed into the set position away from the substrate.

[0055] The higher the source temperature, the greater the evaporation rate of the raw material, and the greater the density of the DAAQ nanowire horizontal array, resulting in a worse linear consistency; when the substrate temperature decreases, the deposition localization of DAAQ organic molecules becomes smaller, and the deposition distribution on the M-plane sapphire is uneven. Preferably, 13 mg of DAAQ powder is placed in a quartz boat and placed in the source temperature zone; the sapphire substrate is placed on an 8-mm-high trough plate and together placed in a quartz boat with an inner diameter of 29 mm, and placed in the growth temperature zone; the distance between the DAAQ powder and the substrate is 20 cm; the temperature of the source temperature zone is 230 °C, the temperature of the growth temperature zone is 70 °C, the carrier gas is N2, the volume flow rate is 90 sccm, the pressure is 16 mbar, and the growth time is 100 min. The deposited horizontal nanowire array has good uniformity and consistency.

[0056] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with specific embodiments and the accompanying drawings, but this does not limit the protection scope of the present invention.

[0057] Unless otherwise specified, the reagents used in the following examples are all commercially available; unless otherwise specified, the methods used in the following examples can be realized by conventional methods.

[0058] The experimental instruments used in the following examples: TF1200-60 tube furnace of Shanghai Micro Furnace Industry Co., Ltd. A quartz tube with an outer diameter, inner diameter, and length of 35 mm, 29 mm, and 1500 mm respectively. D08-4E flow display instrument and D07-19B mass flow controller of Beijing Sevenstar Huachuang Flowmeter Co., Ltd. ME103E / 02 electronic balance of Mettler-Toledo Instruments (Shanghai) Co., Ltd. BILON6-180 ultrasonic cleaner of Shanghai Bilang Instrument Manufacturing Co., Ltd.

[0059] Performance characterization: The SEM image was measured by a ZEISS Gemini 500 field emission scanning electron microscope at an acceleration voltage of 3.00 kV. The XRD pattern was measured by a BRPUKER D8 ADVANCE X-ray diffractometer at an acceleration voltage of 40 kV.

[0060] Reagent: 1,5-diaminoanthraquinone from Alfa Aesar, with a purity of 95%.

[0061] Example 1

[0062] Reference Figure 1-2 , a method for directionally growing a DAAQ horizontal nanowire array, comprising the following steps:

[0063] Step S1: A two-inch M-plane sapphire substrate (i.e., α-Al2O3, crystal plane index (10 0)) Put it into a box furnace for annealing. The annealing steps are as follows: Heat up the temperature of the box furnace to 1600 °C, keep it at a constant temperature for 10 h, and take it out when it cools down to room temperature naturally. The scanning electron microscope (SEM) images of the M-plane sapphire substrate surface before and after heat treatment are as Figure 3 shown, where Figure 3 a is the SEM image of the M-plane sapphire substrate surface before heat treatment, Figure 3 b is the SEM image of the M-plane sapphire substrate surface after heat treatment. The atomic force microscope (AFM) image of the M-plane sapphire substrate surface after heat treatment is as Figure 4 shown.

[0064] At this time, horizontal channels arranged in parallel with a "V"-shaped cross-section will spontaneously form on the M-plane sapphire surface. By Figure 3 , Figure 4 It can be seen that after high-temperature annealing in a box furnace, a single-oriented "V"-shaped channel is spontaneously formed on the M-plane sapphire surface, with its crystal plane index of ±(1 10), a height of 10 - 25 nm, and the width and height of the channels have their uniformity.

[0065] Step S2: Cut the annealed sapphire substrate in S1 into small pieces of 1 cm × 1 cm using a diamond pen, and ultrasonically clean them successively with acetone, isopropyl alcohol, 95% ethanol, deionized water, and 95% ethanol solution to remove surface oil stains and impurities. Then, flush the surface of the M-plane sapphire substrate with nitrogen to remove residual liquid and stains.

[0066] Step S3: Immerse the sapphire substrate in S2 in an OTMS solution (a mixture of 10 ml of n-hexane and 10 μl of OTMS) for surface modification treatment for 1 - 2 h. An octadecylsilane molecular layer is formed on the M-plane sapphire substrate surface, which improves the affinity with DAAQ nanowires and makes the sapphire substrate hydrophobic.

[0067] The water contact angles of the sapphire substrate surface before and after treatment are respectively as Figure 5 , Figure 6 shown. From Figure 5 , Figure 6 the hydrophilic-hydrophobic comparison diagram, it can be seen that after surface modification treatment, the contact angle between the M-plane sapphire substrate and water droplets increases significantly, from 34.2° to 99.5°, the hydrophobicity is enhanced, and the surface energy is reduced.

[0068] Step S4: Directionally grow DAAQ nanowire arrays on the surface of the sapphire substrate processed in Step S3 using a dual-temperature-zone tube furnace device. The detailed steps are as follows: Place 13 mg of DAAQ powder in a quartz boat and place it in the source temperature zone of the quartz tube of the dual-temperature-zone tube furnace; Place the sapphire substrate on a slot plate with a height of 8 mm, and place them together in a quartz boat with an inner diameter of 29 mm, and place it in the growth temperature zone of the quartz tube; The distance between the source powder and the substrate is 20 cm. Set the source temperature to 230 °C, the substrate growth temperature to 70 °C, the carrier gas to N2, the N2 volume flow rate to 90 sccm, the pressure to 16 mbar, and the growth time to 100 min.

[0069] After measuring the distance between the source powder and the substrate, mark the position with a signature pen. And before growth, place the pusher rod quartz boat with the source powder outside the temperature zone of the tube furnace. After heating up to the programmed temperature, then push the DAAQ powder to the set distance from the substrate.

[0070] Use an optical microscope, a scanning electron microscope (SEM), and an atomic force microscope (AFM) to observe the surface morphology of the sample obtained in Step S4 and the length, width, and height information of the DAAQ nanowires, as Figures 8-13 shown, where Figure 8 is an optical microscope image with a scale bar of 200 μm; Figure 9 is an optical microscope image with a scale bar of 10 μm, Figure 10 are SEM images with different scale bars, where the scale bar in Figure a is 10 μm and the scale bar in Figure b is 2 μm; Figure 11 is an AFM image, where Figure a is the AFM image and Figure b is the height curve graph drawn based on Figure a; Figure 12 a-d in are optical microscope images for measuring the length of the nanowire arrays at different positions; Figure 13 are optical microscope images and SEM images for measuring the width of the nanowire arrays at different positions, where Figures a-c are optical microscope images and Figure d is an SEM image.

[0071] Use X-ray diffraction analysis (XRD) to analyze the crystal structures of the sample obtained in Step S5 and the DAAQ powder, and the results are as Figure 14 shown.

[0072] Comparative Example 1

[0073] The difference from Example 1 is that the step of hydrophobic modification in Step S3 is missing, and the others are the same as in Example 1.

[0074] The optical microscope image of the obtained DAAQ nanowire array sample is as Figure 7 shown.

[0075] From Figures 7-9It can be seen that, compared with the sapphire substrate without surface modification treatment, the DAAQ nanowires grown on the surface-modified sapphire substrate can form a directed horizontal nanowire array (such as Figure 8 and Figure 9 ). At the same time, as can be seen from Figure 10 a and Figure 10 b, through this solution, it is possible to grow a horizontal-directed DAAQ nanowire array over a large area, and the distribution uniformity, directivity, and density are all improved. In addition, as can be seen from Figures 11-13 , the length of the DAAQ nanowires grown by this solution can be in the range of 60 μm - 340 μm, the width can be in the range of 500 nm - 1.35 μm, and the height can be in the range of 600 nm - 700 nm.

[0076] From Figure 14 's XRD spectrum, it can be seen that the peak positions and line shapes of the XRD curves of the DAAQ powder and DAAQ nanowires are consistent, indicating that the DAAQ grown in the embodiments of the present invention has high crystallinity and good crystal quality.

[0077] In summary, it can be seen that the growth method of the present invention involves performing a hydrophobic treatment on the M-plane sapphire substrate with horizontally arranged parallel nanogrooves formed on the surface after high-temperature annealing treatment, controlling the contact angle, making it more conducive to the directional growth of the DAAQ nanowire horizontal array. Without the need for an additional growth template, the process flow is simplified. The PVD method is used to grow a directional DAAQ nanowire horizontal array, which is safe and easy to operate. The growth and alignment of the DAAQ nanowires are achieved in one step. The prepared DAAQ single-crystal nanowires have a length in the range of 60 μm - 340 μm, a width in the range of 500 nm - 1.35 μm, and a height of 600 - 700 nm, and have high crystallinity and exhibit a crystal orientation preference growth mode, and can be applied to organic field effect transistors, organic light-emitting diodes, organic photovoltaic cells, or photodetector products.

[0078] The specific embodiments described above have further elaborated on the purpose, technical solutions, and beneficial effects of the present invention. It should be noted that the above are only specific embodiments of the present invention and are not used to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for growing a nanowire array with a DAAQ level, characterized in that, It includes the following steps: Step S1: Anneal the sapphire substrate on the M surface to form horizontally arranged parallel nanochannels on its surface; the depth of the nanochannels is 10 - 25 nm, and the depth distribution is uniform; Step S2: Perform surface hydrophobic modification on the sapphire substrate processed in Step S1, so that the surface contact angle is greater than 95°; Step S3: Grow DAAQ nanowires on the surface of the sapphire substrate processed in Step S2 by chemical vapor deposition.

2. The method for growing a DAAQ level nanowire array according to claim 1, wherein In Step S1, the annealing treatment temperature is 1600 °C and the heat preservation time is 10 h.

3. The method for growing a DAAQ level nanowire array according to claim 1, wherein In Step S2, the hydrophobic modification treatment is achieved by immersing the sapphire substrate in an OTMS solution.

4. The method for growing a DAAQ level nanowire array according to claim 3, wherein The OTMS solution is an OTMS n - hexane solution with a ratio of 1 μl / ml, and the immersion time is 1 - 2 h.

5. The method for growing the DAAQ level nanowire array according to claim 1, wherein In Step S2, before the hydrophobic modification treatment, it also includes a step of cleaning the sapphire substrate. The cleaning is successively carried out by ultrasonic cleaning with acetone, isopropyl alcohol, 95% ethanol, deionized water, and 95% ethanol solution. The ultrasonic cleaning time for each time is 10 min, the ultrasonic power is 135 W, and after ultrasonic cleaning, it is purged with nitrogen.

6. The method for growing a DAAQ level nanowire array according to claim 1, wherein Step S3 is carried out in a two - temperature - zone tube furnace; take 13 mg of DAAQ powder and place it in a quartz boat and place it in the source temperature zone; the sapphire substrate is placed on a slot plate with a height of 8 mm and placed together in a quartz boat with an inner diameter of 29 mm and placed in the growth temperature zone; the distance between the DAAQ powder and the substrate is 20 cm; the temperature of the source temperature zone is 230 °C, the temperature of the growth temperature zone is 70 °C, the carrier gas is N2, the volume flow rate is 90 sccm, the pressure is 16 mbar, and the growth time is 100 min.

7. A DAAQ horizontal nanowire array prepared by using the method for growing a DAAQ horizontal nanowire array according to any one of claims 1 - 6.

8. The DAAQ horizontal nanowire array according to claim 7, wherein, The length of the DAAQ nanowire is 60 - 340 μm, the width is 500 nm - 1.35 μm, and the height is 600 - 700 nm.

9. Application of the DAAQ horizontal nanowire array according to claim 7 or 8 in organic field - effect transistors, organic light - emitting diodes, organic photovoltaic cells, or photodetector products.

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