A method for magnetron sputter deposition of nanowires

Abstract

The application relates to the technical field of nanowire preparation, and provides a method for preparing nanowires through magnetron sputtering deposition, wherein a target material and a substrate are arranged in a deposition area of a magnetron sputtering device, the substrate is arranged in a spaced mode relative to the target material, a bias electrode electrically insulated from the substrate is arranged on the substrate, the bias electrode is connected with a power supply, and a bias voltage is applied to the bias electrode through the power supply during a magnetron sputtering deposition process in which a plasma is formed, so that the bias electrode forms an electrical boundary on the substrate, the plasma state of a deposition area of the substrate and / or the motion state of charged particles are regulated, and the deposition of the target material forms nanowires on the substrate, the nanowires being perpendicular to the surface of the substrate. The bias electrode arranged on the substrate is used to change the transport state of the plasma and / or the charged particles in the deposition area of the substrate during the magnetron sputtering deposition process, so that the nanowires are directly formed, thereby providing a method for preparing nanowires without a catalyst, a growth template, a mask plate, and a patterned pretreatment substrate.

Description

Technical Field

[0001] This invention relates to the field of nanowire fabrication technology, and more specifically to a method for fabricating nanowires by magnetron sputtering. Background Technology

[0002] Nanowires are a class of one-dimensional nanostructure materials with large aspect ratios. Due to their large specific surface area, significant size effect, and unique electrical, optical, and surface properties, nanowires have broad application prospects in photodetectors, solar cells, sensors, light-emitting devices, field emission devices, and micro / nanoelectronic devices. Especially for semiconductor nanowires, their diameter, length, orientation, crystallinity, and distribution on the substrate surface all have a significant impact on material and device performance. Therefore, realizing large-area, rapid, and orientation-controllable nanowires on substrate surfaces is one of the important technological directions in the field of nanomaterial fabrication.

[0003] Currently, nanowire fabrication methods mainly include physical vapor deposition (PVD). PVD offers advantages such as high deposition rates, wide applicability to various materials, relatively simple processes, and ease of large-area deposition. Among these methods, magnetron sputtering has been widely used for thin film fabrication of metals, semiconductors, and compound materials. In magnetron sputtering, plasma-generated ions bombard the target material, causing target atoms or particles to escape from the target surface and be transported in the gas phase before being deposited on the substrate surface. By adjusting process parameters such as sputtering power, working gas pressure, gas composition, target-substrate distance, and substrate temperature, the composition, crystallinity, and microstructure of the deposited material can be controlled.

[0004] Chinese patent document CN122658734A discloses a high-performance flexible transparent conductive thin film and its preparation method. It is known that existing technologies utilize magnetron sputtering to form continuous or near-continuous thin films. Under typical deposition conditions, the growth species reaching the substrate surface undergo adsorption, nucleation, island growth, and grain merging. As the deposition process continues, each crystal nucleus grows simultaneously in both the lateral and longitudinal directions, gradually forming a continuous or near-continuous film.

[0005] Existing technologies typically require the use of catalysts, pre-fabricated nanostructures, templates, patterned substrates, special crystalline substrates, or higher substrate temperatures to promote nucleation at specific locations or preferred growth in specific crystal orientations. These additional processes not only increase the number of fabrication steps but may also limit the choice of substrate materials and deposition area. For example, for amorphous substrates such as glass, the lack of crystalline surfaces that provide lattice matching and preferred orientation makes it impossible to directly obtain large-area, high aspect ratio nanowires with distinct orientations at lower substrate temperatures. Summary of the Invention

[0006] The technical problem to be solved by the present invention is how to form nanowires directly on a substrate by magnetron sputtering without the need for catalysts, growth templates, masks or patterned pre-treated substrates.

[0007] The present invention solves the above-mentioned technical problems through the following technical means: This invention provides a method for preparing nanowires by magnetron sputtering deposition. A target and a substrate are arranged in the deposition area of ​​a magnetron sputtering device, with the substrate and target spaced apart. A bias electrode electrically insulated from the substrate is arranged on the substrate and connected to a power supply. During the magnetron sputtering deposition process that forms plasma, a bias voltage is applied to the bias electrode by the power supply, so that the bias electrode forms an electrical boundary on the substrate. The plasma state and / or the transport state of charged particles in the substrate deposition area are controlled, so that the target deposit forms nanowires perpendicular to the substrate surface on the substrate.

[0008] Beneficial effects: This invention utilizes a bias electrode disposed on the substrate to change the transport state of plasma and / or charged particles in the substrate deposition area during magnetron sputtering deposition, transforming the magnetron sputtering deposition process, which originally tends to form continuous thin films, into a growth process that can directly form one-dimensional nanostructures. This provides a simple process that does not require catalysts, growth templates, masks, patterned pre-treated substrates, or other materials, and is suitable for the rapid fabrication of nanowires.

[0009] Preferably, the bias electrodes are continuously or intermittently arranged around the deposition area of ​​the substrate, forming a ring or polygon on the substrate.

[0010] Preferably, the power supply includes one or more of DC power supply, AC power supply, and pulse power supply.

[0011] Preferably, the bias voltage is +20~+70V.

[0012] More preferably, the bias voltage is +40~+60V.

[0013] Preferably, the distance between the target and the substrate is 8~15cm.

[0014] Preferably, the substrate is an insulating substrate.

[0015] More preferably, the insulating substrate is one of a glass substrate, a soda-lime glass substrate, or a borosilicate glass substrate.

[0016] Preferably, the target material is a semiconductor material.

[0017] Preferably, the semiconductor material includes one or more of CdS, ZnS, CdSe, ZnSe, and CdTe.

[0018] More preferably, the target material is CdS.

[0019] Preferably, the substrate is heated during the magnetron sputtering deposition process, and the heating temperature is 20~400℃.

[0020] Beneficial effects: The present invention heats the substrate to maintain a state conducive to the diffusion of deposited species on the surface and the preferential growth of crystals.

[0021] Preferably, the method includes the following steps: setting a target and a substrate in the deposition area of ​​the magnetron sputtering apparatus, with the substrate and the target spaced apart; setting a bias electrode electrically insulated from the substrate on the substrate, the bias electrode being connected to a power supply; evacuating the deposition area and introducing a working gas, forming a plasma for magnetron sputtering deposition in the deposition area; applying a bias voltage to the bias electrode through the power supply to regulate the plasma state and / or the transport state of charged particles in the substrate deposition area, and transporting the deposit from the target to the substrate surface through magnetron sputtering deposition; changing the growth behavior of the target on the substrate surface under the electrical boundary formed by the bias electrode, so that the target grows on the substrate surface perpendicular to the substrate to form nanowires.

[0022] Beneficial effects: This invention eliminates the need to use a mask to define the nanowire growth area, pre-form nanowire patterns using micro-nano processing methods such as photolithography, and eliminates the need for catalysts and growth templates, thus simplifying the nanowire fabrication process and enabling rapid nanowire fabrication.

[0023] Preferably, magnetron sputtering includes one of DC magnetron sputtering, radio frequency magnetron sputtering, intermediate frequency magnetron sputtering, pulsed DC magnetron sputtering, or high-power pulsed magnetron sputtering.

[0024] Compared with the prior art, the present invention has the following beneficial effects: 1. Direct nanowire growth without a mask. This invention eliminates the need for masks, photolithography, electron beam lithography, or other patterning processes to define the nanowire growth position. Nanowires can be directly deposited on the substrate surface using magnetron sputtering, significantly reducing the number of nanowire fabrication steps.

[0025] 2. Facilitates large-area growth. The bias electrode is placed around the deposition area of ​​the substrate, and the growth of nanowires is promoted by controlling the substrate deposition environment. It does not rely on point-by-point processing or local nanopatterning, and can form nanowires on a large-area substrate.

[0026] 3. Fast growth rate and easy to scale up. This invention can use a magnetron sputtering device to prepare nanowires, which has the advantages of high deposition rate, mature equipment and easy expansion of deposition area, which is conducive to the large-scale production of nanowires.

[0027] 4. No pre-prepared nanoscale catalyst required. This invention enables direct growth of nanowires without the need for pre-prepared catalysts or nanoscale nucleating particles, thereby reducing the risk of catalyst contamination and simplifying the substrate pretreatment process.

[0028] 5. No growth template required. This invention does not rely on growth templates with pre-fabricated nanopores, such as porous alumina, to restrict the morphology of nanowires, thus eliminating the need for template preparation, filling, and subsequent template removal.

[0029] 6. This invention enables the direct formation of oriented nanowires on amorphous substrates. By controlling the deposition environment through a bias electrode, this invention promotes one-dimensional preferred growth on amorphous substrates such as glass that lack lattice matching, thereby reducing the dependence of nanowire growth on single-crystal substrates.

[0030] 7. Excellent nanowire orientation. The electrical boundary formed by the bias electrode during magnetron sputtering deposition enables the target material to form nanowires in the substrate and grow in a direction perpendicular to the substrate surface, thereby obtaining large-area oriented nanowires. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the method for preparing CdS nanowires in Example 1 of the present invention; Figure 2 This is a scanning electron microscope image of the CdS nanowires prepared in Example 1 of the present invention; Figure 3 for Figure 2 Scanning electron microscope image of a portion of the CdS nanowires after they have been pressed down; Figure 4 The XRD pattern of CdS nanowires prepared in Example 1 of this invention; Figure 5 This is a side SEM image of the CdS nanowires prepared in Example 1 of the present invention; Figure 6 Scanning electron microscope image of CdS nanowires prepared in Example 2 of this invention; Figure 7 This is a scanning electron microscope image of the CdS nanowires prepared in Example 3 of the present invention; Figure 8 The image shown is a scanning electron microscope (SEM) image of the CdS thin film prepared in Comparative Example 1 of this invention. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] Unless otherwise specified, all test materials and reagents used in the following examples are commercially available.

[0034] Unless otherwise specified in the embodiments, the techniques or conditions described in the literature in this field or in accordance with the product manual may be followed.

[0035] Example 1 according to Figure 1 As shown, this embodiment provides a method for preparing CdS nanowires by magnetron sputtering deposition, specifically including the following steps: A target 1 and a substrate 5 are disposed in the deposition area of ​​the radio frequency magnetron sputtering apparatus, with a 15 cm gap between them. The target 1 is disposed above the substrate 5 and is CdS. The substrate 5 is fixedly supported by a bracket 6 and is a glass substrate. A bias electrode 4 electrically insulated from the glass substrate 5 is disposed on the glass substrate 5 and is connected to a power supply 7. The bias electrode 4 is continuously disposed around the deposition area of ​​the glass substrate 5 to form a ring. A ceramic insulating sheet is disposed between the bias electrode 4 and the glass substrate 5 to achieve electrical insulation.

[0036] During magnetron sputtering deposition, a bias voltage is applied to the annular bias electrode 4 through the power supply 7, so that the annular bias electrode 4 forms a potential difference with respect to the plasma 2 in the deposition area, thereby changing the electric field distribution, plasma sheath state and charged particle transport behavior in the deposition area of ​​the glass substrate 5.

[0037] The deposition area is evacuated and argon gas is introduced at a pressure between 1.9 and 2.1 Pa. The argon gas is uniformly injected around the target material 1 through a gas distribution ring. A bias voltage of approximately +50V is applied to the bias electrode 4. During the deposition process, the glass substrate 5 is heated to approximately 200°C. Under the combined action of the electrical boundary formed by the annular bias electrode 4 and the deposition conditions, the nucleation and crystal growth behavior of the CdS deposit on the surface of the glass substrate 5 is altered, inhibiting the formation of a continuous CdS film and promoting the one-dimensional growth of the CdS deposit along the preferred growth direction. This results in the formation of a large area of ​​CdS nanowires 3 on the surface of the glass substrate 5. The CdS nanowires 3 grow perpendicular to the surface of the glass substrate 5, as shown in the figure below. Figure 2 and Figure 3 As shown.

[0038] according to Figure 4 and Figure 5 XRD results show that a well-crystallized hexagonal cadmium sulfide lattice structure was formed, with the broad amorphous peaks at 20-40 degrees originating from the glass substrate, and the remaining characteristic peaks conforming to the standard card for hexagonal cadmium sulfide. After pressing the CdS nanowires, the scanning electron microscope observation results show that the cadmium sulfide crystals have a nanowire structure with a typical diameter on the order of tens of nanometers, which proves the successful preparation of cadmium sulfide nanowires.

[0039] Example 2 This embodiment provides a method for preparing CdS nanowires by magnetron sputtering deposition. The difference between this embodiment and Embodiment 1 is that the applied bias voltage is 20V.

[0040] according to Figure 6 It can be seen that at this point, the nucleation and growth mode of cadmium sulfide changes from horizontal film formation to island-like growth. It begins to preferentially grow at dispersed sites in a direction perpendicular to the glass substrate, forming nanospherical protrusion regions. The process conditions in this embodiment represent the minimum bias voltage critical transition point for cadmium sulfide to change from horizontal uniform film formation to vertical growth.

[0041] Example 3 This embodiment provides a method for preparing CdS nanowires by magnetron sputtering deposition. The difference between this embodiment and Embodiment 1 is that the applied bias voltage is 70V.

[0042] according to Figure 7 It can be seen that the CdS nanowires still maintain good vertical orientation consistency at this point, and a cadmium sulfide nanowire array can be obtained. However, random substrate edge discharge begins to appear during the growth process, damaging the nanowire array at the substrate edge. The process conditions in this embodiment represent the highest critical bias voltage value for the growth of the cadmium sulfide nanowire array.

[0043] Example 4 This embodiment provides a method for preparing ZnS nanowires by magnetron sputtering deposition. The difference between this embodiment and Embodiment 1 is that the CdS target is replaced with a ZnS target, and ZnS nanowires perpendicular to the glass substrate 5 are finally obtained.

[0044] Example 5 This embodiment provides a method for preparing CdSe nanowires by magnetron sputtering deposition. The difference between this embodiment and Embodiment 1 is that the CdS target is replaced with a CdSe target, and CdSe nanowires perpendicular to the glass substrate 5 are finally obtained.

[0045] Example 6 This embodiment provides a method for preparing ZnSe nanowires by magnetron sputtering deposition. The difference between this embodiment and Embodiment 1 is that the CdS target is replaced with a ZnSe target, and ZnSe nanowires perpendicular to the surface of the glass substrate 5 are finally obtained.

[0046] Example 7 This embodiment provides a method for preparing CdS nanowires by magnetron sputtering deposition. The difference between this embodiment and Embodiment 1 is that the glass substrate is replaced with a soda-lime glass substrate, and CdS nanowires 3 perpendicular to the soda-lime glass substrate are finally obtained.

[0047] Example 8 This embodiment provides a method for preparing CdS nanowires by magnetron sputtering deposition. The difference between this embodiment and Embodiment 1 is that the glass substrate is replaced with a borosilicate glass substrate, and CdS nanowires 3 are finally obtained perpendicular to the borosilicate glass substrate.

[0048] Comparative Example 1 This comparative example provides a method for preparing CdS thin films by magnetron sputtering deposition. The difference between this comparative example and Example 1 is that no bias voltage is applied to the bias electrode 4. In this case, the growth behavior of the CdS deposit in the target 1 on the surface of the glass substrate 5 is consistent with the film formation behavior in a conventional magnetron sputtering deposition process, forming a continuous CdS thin film, specifically as follows... Figure 8 As shown.

[0049] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing nanowires by magnetron sputtering deposition, characterized in that, A target and a substrate are arranged in the deposition area of ​​a magnetron sputtering device, with the substrate and target spaced apart. A bias electrode electrically insulated from the substrate is arranged on the substrate and connected to a power supply. During the magnetron sputtering deposition process that forms plasma, a bias voltage is applied to the bias electrode by the power supply, so that the bias electrode forms an electrical boundary on the substrate. This controls the plasma state and / or the transport state of charged particles in the substrate deposition area, so that the target deposit forms nanowires perpendicular to the substrate surface on the substrate.

2. The method for preparing nanowires by magnetron sputtering deposition according to claim 1, characterized in that, The bias electrodes are arranged continuously or intermittently around the deposition area of ​​the substrate, forming a ring or polygon on the substrate.

3. The method for preparing nanowires by magnetron sputtering deposition according to claim 2, characterized in that, The power supply includes one or more of the following: DC power supply, AC power supply, and pulse power supply.

4. The method for preparing nanowires by magnetron sputtering deposition according to claim 3, characterized in that, The bias voltage is +20~+70V.

5. The method for preparing nanowires by magnetron sputtering deposition according to claim 2, characterized in that, The distance between the target and the substrate is 8~15cm.

6. The method for preparing nanowires by magnetron sputtering deposition according to claim 1, characterized in that, The substrate is an insulating substrate.

7. The method for preparing nanowires by magnetron sputtering deposition according to claim 1, characterized in that, The target material is a semiconductor material.

8. The method for preparing nanowires by magnetron sputtering deposition according to claim 7, characterized in that, Semiconductor materials include one or more of CdS, ZnS, CdSe, ZnSe, and CdTe.

9. The method for preparing nanowires by magnetron sputtering deposition according to claim 1, characterized in that, During the magnetron sputtering deposition process, the substrate is heated to a temperature of 20~400℃.

10. The method for preparing nanowires by magnetron sputtering deposition according to any one of claims 1-9, characterized in that, Includes the following steps: A target and a substrate are arranged in the deposition area of ​​a magnetron sputtering apparatus, with the substrate and target spaced apart. A bias electrode electrically insulated from the substrate is placed on the substrate and connected to a power supply. The deposition area is evacuated and a working gas is introduced, forming a plasma for magnetron sputtering deposition in the deposition area. A bias voltage is applied to the bias electrode by the power supply to regulate the plasma state and / or the motion state of charged particles in the substrate deposition area. The magnetron sputtering deposition transports the deposit from the target to the substrate surface. Under the electrical boundary formed by the bias electrode, the growth behavior of the target on the substrate surface is changed, causing the target to grow on the substrate surface perpendicular to the substrate to form nanowires.

Images