WO2011099750A2 - Nanowire alignment method using a three-dimensional structure, three-dimensional framework for nanowire alignment, manufacturing method for a three-dimensional framework for nanowire alignment, and transfer printing method for an aligned nanowire - Google Patents

Abstract

A transfer printing method for an aligned nanowire according to an embodiment of the present invention comprises: aligning a nanowire in a groove formed on the upper surface of a first substrate; and printing the nanowire aligned in the groove of the first substrate into a second substrate by using a transfer printing member having elasticity and adhesion.

Description

Nanowire alignment method using three-dimensional structure, three-dimensional framework for nanowire alignment, manufacturing method of three-dimensional framework for nanowire alignment, and method for transferring aligned nanowire

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for transferring nanowires used in nanowire network devices and the like, and more particularly, to a method of aligning nanowires and transferring the aligned nanowires to a desired substrate using transfer printing.

Nanowires are wire-shaped materials with nano-diameter diameters and have potential applications in a variety of electronic device applications. In particular, nanowire network devices are attracting great attention because they can be applied to various industrial fields such as transistors or sensors using nanowires, and many researches are currently being conducted worldwide.

Since conventional silicon-based transistors have already reached a certain limit, a new concept and structure of nanomaterials has been proposed and researched actively as a next-generation device capable of overcoming the limitations of existing device performance. . As such a next-generation device, nanomaterials are in the spotlight, and research on nanowires having a one-dimensional (1-D) structure is being actively conducted. Nanowires have excellent electrical and optical properties and at the same time have a high selectivity in distinguishing chemicals from energy band structures, crystalline (cryatalline quality) and mobility of charge carriers. Because of its excellent mobility, it is used in various nano devices such as sensors and transistors. Another advantage of nanostructures is that they can be moved to a desired substrate at low temperatures after they are grown, thereby releasing various limitations caused by high silicon-based high process temperatures. When the process is performed at a high temperature by using a flexible substrate made of a material such as a polymer, deformation of the substrate occurs, and thus there is a limitation in applying a conventional silicon-based process method. However, the method of transferring nanomaterials is expected to be advantageous in a variety of industries that use flexible substrates because they can be processed at low temperatures.

To fabricate nanowire transistors, one can locate an arbitrarily positioned nanowire and use electron beam lithography. However, in this case, since the time required for manufacturing the device is too long and only one device can be made at a time, it is difficult to mass-produce, so that practical application and application to the electronic industry are difficult. In order to solve this problem, efforts are being actively made to study devices using nanowire networks (for example, nanowires are entangled with each other). As a method of forming a nanowire network, there is a method of stamping a nanowire by pressing the substrate on which the nanowire is grown onto another desired substrate and a method of using a nanowire dispersed in a liquid solvent. . By using this method, mass production is possible by eliminating or reducing the electron-beam lithography process. However, since the nanowire network obtained by this method is difficult to align in a desired pattern where desired, the electrical and optical performance of the device is low.

One embodiment of the present invention provides a method capable of effectively transferring nanowires or nanowire networks aligned to desired locations of a desired substrate.

Another embodiment of the present invention provides a three-dimensional framework for efficiently collecting and aligning nanowires where desired in nanowire device fabrication.

Yet another embodiment of the present invention provides a method of manufacturing a three-dimensional framework for efficiently collecting and aligning nanowires in a desired place in manufacturing nanowire devices.

Another embodiment of the present invention provides an electronic device using nanowires.

An ordered nanowire transfer method according to an embodiment of the present invention comprises the steps of: aligning a nanowire in the groove of the first substrate having a groove on the upper surface; And transferring the nanowires aligned in the grooves of the first substrate to another second substrate by using a transfer member having elasticity and adhesion.

The aligned nanowire transfer method may include: aligning the nanowires and transferring the aligned nanowires to a second substrate, using a removal member having an adhesive force to form a first substrate outside the groove. The method may further include removing the nanowire located on the upper surface.

Before the step of transferring the aligned nanowire to the second substrate, the step of aligning the nanowire and the step of removing the nanowire located on the upper surface of the first substrate outside the groove may be further performed.

Aligning the nanowires may include preparing a first substrate having a three-dimensional structure having a groove shape on an upper surface thereof; Providing a solution in which nanowires are dispersed (nanowire dispersion solution) on a three-dimensional structure of the first substrate; And drying the nanowire dispersion solution provided on the three-dimensional structure to align the nanowires in the grooves of the first substrate.

The groove may have a trench-shaped groove extending in one direction. The groove may have a shape in which both sidewalls of the groove are inclined so that the width of the groove becomes narrower as the depth in the groove increases. The cross-sectional shape of the groove may be V-shaped or trapezoidal. A plurality of grooves may be formed on the first substrate.

The removal member may have an elastic force together with the adhesive force. The transfer member may be formed of PDMS. The removal member may be formed of PDMS.

According to another embodiment of the present invention, a nanowire alignment method includes preparing a substrate having a three-dimensional structure in which trench grooves in which both inner walls of the groove are inclined are formed so that the width in the groove becomes narrower as the depth in the groove becomes deeper. step; Providing a solution in which nanowires are dispersed on the three-dimensional structure; And drying the solution provided on the three-dimensional structure to align the nanowires in the trench grooves along the length direction of the trench grooves. A plurality of trench grooves may be formed in the three-dimensional structure, and the plurality of trench grooves may extend in parallel to each other. The trench groove may have a cross-sectional shape of a V-shaped or truncated inverse pyramid.

According to an embodiment of the present invention, the preparing of the substrate having the three-dimensional structure may include preparing a mother substrate having a planar top surface; Etching the upper surface of the mother substrate to form a trench groove in which both inner walls of the groove are inclined so that the width of the groove becomes narrower as the depth in the groove becomes deeper. The mother substrate may be a silicon substrate.

According to another embodiment, the preparing of the substrate having the three-dimensional structure may include preparing a mother substrate having a planar top surface; Etching the upper surface of the mother substrate to form trench grooves in which both inner walls of the groove are inclined so that the width of the groove becomes narrower as the depth in the groove becomes deeper; Coating a first polymer material on the mother substrate where the trench grooves are formed to form a polymer layer which completely fills the trench grooves; After separating the polymer layer from the mother substrate and coating a second polymer material on the separation surface of the polymer layer, trench grooves in which both inner walls of the grooves are inclined so that the width in the grooves becomes narrower as the depth in the grooves becomes deeper. Forming a three-dimensional mold which is formed and has a bottom portion of the trench groove opened as an opening; And separating the three-dimensional framework from the polymer layer and placing it on a substrate that requires nanowire alignment.

The preparing of the substrate having the three-dimensional structure may include: separating the polymer layer from the mother substrate and before coating the second polymer material on the separation surface of the polymer layer on the separation surface of the polymer layer. The method may further include forming a thin film for layer separation.

The nanowire alignment method may include reusing the three-dimensional framework by separating the three-dimensional framework from the substrate and disposing the three-dimensional framework on the substrate after the alignment of the nanowires in the trench grooves. It may further include.

The three-dimensional frame for aligning nanowires according to the embodiment of the present invention is a frame for aligning nanowires arranged on a substrate on which nanowires are to be arranged, and trench grooves are formed on the opposite side of the surface disposed on the substrate. As the trench groove deepens in the groove, both inner walls of the groove are inclined so that the width of the trench narrows, and the bottom of the trench groove is opened as an opening.

Method of manufacturing a three-dimensional framework for aligning nanowires according to an embodiment of the present invention comprises the steps of preparing a mother substrate having a planar top surface; Etching the upper surface of the mother substrate to form trench grooves in which both inner walls of the groove are inclined so that the width of the groove becomes narrower as the depth in the groove becomes deeper; Coating a first polymer material on the mother substrate where the trench grooves are formed to form a polymer layer which completely fills the trench grooves; And separating the polymer layer from the mother substrate and coating a second polymer material on the pyramid structure formed on the upper surface of the polymer layer, so that inner walls of both grooves are narrow so that the width in the groove becomes narrower as the depth in the groove increases. And forming a three-dimensional frame in which a photo trench groove is formed and a bottom portion of the trench groove is opened as an opening.

An electronic device according to an embodiment of the present invention includes a substrate having grooves that become narrower in width, and nanowires aligned in the grooves.

According to an embodiment of the present invention, nanowires or nanowire networks well aligned in a desired pattern can be easily transferred to a desired substrate in a short time. Thus, it can be effectively applied to mass production at low cost of nanowire devices or nanowire network devices having well aligned nanowires. In addition, by spraying the nanowire dispersion solution and then drying and removing the nanowires attached to the unnecessary parts by repeating the process there is an advantage that can effectively control the nanowire density of the nanowire network. By applying the aligned nanowire transfer method according to an embodiment of the present invention to nanowire transfer to a flexible substrate, it can be effectively used for fabricating flexible electronics.

According to the embodiment of the present invention, it is possible to obtain a substrate structure in which nanowires are aligned in a desired direction at low cost in a short time. The substrate structure in which the nanowires are aligned may be used in nanowire devices such as nanowire network devices. In addition, by using the embodiment of the present invention, a device in which nanowires are aligned can be mass produced. In addition, by using a three-dimensional frame formed with the trench grooves described above, apart from the substrate (for example, silicon semiconductor substrate) used in the nanowire device, the nanowire on the substrate is not etched without separately etching the substrate requiring nanowire alignment. Can be easily aligned. In addition, the three-dimensional framework can be repeatedly reused for the substrates that require nano-wire alignment, which has the advantage of aligning the nano-wires on multiple substrates in one three-dimensional framework.

1 is a schematic diagram illustrating a process of aligning nanowires in an aligned nanowire transfer method according to an embodiment of the present invention.

FIG. 2 is a schematic diagram illustrating a process of removing nanowires attached to an undesired portion (the upper surface of the substrate outside the groove) after the nanowire alignment in the aligned nanowire transfer method according to an embodiment of the present invention.

3 is a micrograph showing the change in density of aligned nanowires.

4 is a diagram illustrating a process of transferring an aligned nanowire or a nanowire network to another desired substrate.

5 is a diagram illustrating a nanowire network transferred to a material having elasticity and adhesion during aligned nanowire transfer processes according to an embodiment of the present invention ((a) and (b)), and the nanowire network is flexible again. It is a figure (c) which shows what was transferred to the board | substrate.

6 to 8 are views for explaining the nanowire alignment method according to an embodiment of the present invention.

9 is a cross-sectional view of a three-dimensional frame for aligning nanowires according to an embodiment of the present invention.

10 is a plan view of the three-dimensional framework shown in FIG.

11 to 14 are views for explaining a nanowire alignment method according to another embodiment of the present invention.

15 to 18 are views for explaining a method of manufacturing a three-dimensional frame for aligning nanowires according to an embodiment of the present invention.

19 to 20 are views for explaining the reuse of the three-dimensional framework for aligning nanowires according to an embodiment of the present invention.

21 is a scanning electron microscope (SEM) photograph showing a V-shaped trench groove formed in a silicon substrate through wet etching and a trench groove having a truncated inverted pyramid cross-sectional shape.

FIG. 22 is a SEM photograph showing nanowires aligned in trench trenches. FIG.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. However, embodiments of the present invention may be modified in various other forms, and the scope of the present invention is not limited to the embodiments described below. Shapes and sizes of the elements in the drawings may be exaggerated for clarity, elements denoted by the same reference numerals in the drawings are the same elements.

Aligned Nanowire  or Nanowire  Transcription method of network

1 is a schematic diagram illustrating a process of aligning nanowires in an aligned nanowire transfer method according to an embodiment of the present invention. According to this embodiment, after aligning the nanowires in the grooves of the substrate (first substrate) having a groove on the upper surface, the nanowires are separated using a transfer member (for example, a PDMS substrate) having elasticity and adhesion. By transferring the transfer member to the desired other substrate (second substrate), it is possible to form a well aligned nanowire or a nanowire network on the desired substrate.

Referring to FIG. 1A, in order to align nanowires on a substrate, first, a first substrate 101 having a three-dimensional structure having a groove shape on an upper surface thereof is prepared. In FIG. 1, the groove formed on the upper surface of the first substrate 101 has a trench shape extending in one direction of a trapezoidal cross section, but the present invention is not limited thereto. For example, a groove having a V-shaped cross section may be used. In addition, the shape of the groove bottom may have various shapes and sizes desired to form a desired nanowire or nanowire network pattern. As illustrated in FIG. 1, both sidewalls of the groove may be inclined so that the width of the groove becomes narrower as the depth in the groove deepens. A plurality of such grooves may be formed on the upper surface of the first substrate 101, and the plurality of grooves may extend in parallel with each other. Such grooves may be formed, for example, by wet etching or dry etching of the silicon substrate. When the silicon substrate is etched with KOH while the stripe-shaped etching region is opened with the etching mask on the silicon substrate, a groove shape as illustrated in FIG. 1 may be easily formed.

After the first substrate 101 is prepared, a solution (nanowire dispersion solution) 60 in which the nanowires 10 are dispersed is sprayed on the three-dimensional structure (upper surface) of the first substrate 101. As the nanowire dispersion solution 60, for example, a solution obtained by dispersing the nanowire in a solvent such as isopropyl alcohol and then performing a sonication well may be used.

As shown in FIG. 1 (b), by sufficiently drying the nanowire dispersion solution 60 sprayed on the three-dimensional structure of the first substrate 101, the nanowires are lowered in the three-dimensional structure, that is, at the bottom of the groove. Is sorted on. This results in a nanowire network that is well aligned in the desired pattern.

The nanowires or nanowire networks aligned as described above can be transferred to other desired substrates using a transfer member made of a material having elasticity and adhesion. For example, PDMS may be used as a material having elasticity and adhesion. After forming the nanowire networks well aligned in the grooves as described with reference to FIG. 1, the nanowire networks may be transferred to another desired substrate by using a PDMS member having elasticity and adhesion. However, according to the process shown in Fig. 1, since the nanowire 10 is also attached to an unwanted portion (upper surface portion of the first substrate outside the groove) other than the groove pattern of the first substrate 101, It is desirable to remove the attached nanowires before the transfer process. FIG. 2 is a cross-sectional view showing such an unnecessary nanowire removal process, and the process shown in FIG. 2 may be performed following the process shown in FIG. 1.

Referring to FIG. 2A, not only the nanowires 10 are aligned in the grooves of the first substrate 101 through the nanowire alignment process of FIG. 1 described above, but also the desired outside of the grooves of the first substrate 101. Nanowire (10a) can also be attached to the upper surface portion. As a result, the removal member 201 having the adhesive force is placed on the first substrate 101 and a weak pressure is applied to the removal member 201 (FIG. 2B). Then, the removal member 201 is separated from the first substrate 101, so that the nanowire 10a that has risen in an undesired position is stuck to the removal member 201 and detached from the first substrate 101 (Fig. 2 (c)). Accordingly, the nanowires can be aligned only to a desired portion (groove bottom) of the first substrate 101. The removal member may have an elastic force together with the adhesive force, and for example, a member made of PDMS may be used as the removal member.

It is difficult to form a nanowire network of a desired density or a high density in the case of a nanowire network that has been studied in the past, but in an embodiment of the present invention, the nanowire network may vary depending on the number of times the nanowire dispersion solution is sprayed onto the first substrate. Has the advantage of adjusting the line density. By repeatedly performing the process of FIG. 1 (the process of spraying and drying the nanowire dispersion solution) of FIG. 1 and the process of FIG. At the bottom of the groove, a nanowire network of desired density can be obtained. For example, spraying nanowire dispersion (FIG. 1 (a)) → drying the dispersion (FIG. 1 (b)) → removing the unwanted nanowires (FIG. 2) → spraying the nanowire dispersion again (FIG. 1 (a)). ¡Æ drying of the dispersion (FIG. 1 (b)) may be repeated twice, such as removal of nanowires from undesired locations (FIG. 2), and the nanowire pattern or pattern of higher density You can get a route network.

3 is a micrograph showing changes in the density of nanowires aligned in a groove by repeatedly performing the processes of FIGS. 1 and 2. 3A shows a plan view photograph of a first substrate having grooves formed therein. The nanowire network (nanowire pattern) as shown in FIG. 3 (b) was obtained by aligning the nanowires by performing the above-described processes of FIGS. 1 and 2 on the first substrate shown in FIG. Then, by repeating the process of FIGS. 1 and 2 on the first substrate again, the density of well-aligned nanowires was increased as shown in FIG.

As described above, after removing some of the nanowires 10a that have been raised to the undesired place, a process of transferring the nanowires or the nanowire network well aligned in the grooves of the first substrate 101 to another substrate is performed. 4 is a diagram illustrating a process of transferring an aligned nanowire or a nanowire network to another desired substrate.

After aligning the nanowires 10 in the grooves of the first substrate 101 as shown in FIG. 4 (a), elastic and adhesive forces are applied on the first substrate 101 as shown in FIG. 4 (b). Put the transfer member 301 having a strong pressure. In this case, when the nanowire network in the groove of the first substrate 101 is applied to a degree enough to transfer all of the nanowire networks to the transfer member, the transfer member 301 is elastic, so the transfer member 301 is under pressure. Can enter the groove and attach to the nanowire network. The nanowire network is then transferred to the transfer member 301 by separating the transfer member 301 from the first substrate 101 (Fig. 4 (c)). Thereafter, as shown in FIG. 4 (d), when the network of the nanowires 10 attached to the transfer member 301 is transferred to another second substrate 401 to be aligned with the nanowires, FIG. As shown, a well aligned network of nanowires 10 transferred to the second substrate 401 can be obtained. As the transfer member 301, for example, a member made of a PDMS material having elasticity and adhesion may be used. By controlling the ratio of the synthetic resin (resin) material and the curing agent (curing agent) material constituting the PDMS there is an advantage that can control the elasticity and adhesion.

By using the above-described transfer method, it is possible to obtain an advantage that the well-aligned nanowire network can easily form a well-aligned nanowire network anywhere regardless of the type of substrate (rigid substrate, flexible substrate). For example, a nanowire network having a desired pattern and a desired density can be easily formed on a flexible substrate such as PET. Mass production of nanowire network devices is possible, and the process is simple. Providing or transferring the nanowire dispersion solution can be performed at room temperature or at low temperature, thereby avoiding problems such as deformation of the substrate by the high temperature process and limitation of substrate selection. In addition, as described above, according to the number of times of spraying the nanowire dispersion solution on the first substrate and drying the same, an advantage of easily adjusting the nanowire density of the aligned nanowire network may be obtained.

5 is a diagram illustrating a nanowire network transferred to a material having elasticity and adhesion during aligned nanowire transfer processes according to an embodiment of the present invention ((a) and (b)), and the nanowire network is flexible again. It is a figure (c) which shows what was transferred to the board | substrate. Referring to FIGS. 5A and 5B, a nanowire network transferred onto a PDMS member through the process of FIGS. 1 and 2 described above is shown. As shown in FIG. 5 (c), this nanowire network can be transferred to another substrate such as PET through the process of FIG. 4.

Nanowire  Sort method

6 to 8 are diagrams for explaining the nanowire alignment method according to an embodiment of the present invention. Referring to FIG. 6, a substrate 501 on which an aligned nanowire, for example, a silicon substrate, is to be disposed is prepared. Then, as shown in FIG. 7, the trench 505 is formed by etching the upper surface of the substrate 501 through wet or dry etching. As the trench grooves 505 become deeper in the grooves, both inner walls of the grooves are inclined so that the widths in the grooves become narrower. The cross-sectional shape of the trench grooves 505 may be, for example, an inverted pyramid cross-sectional shape having a sharp V-shaped bottom or a flat truncated bottom. As shown in FIG. 2, a plurality of trench grooves 505 may be formed, and in particular, the plurality of trench grooves 505 may extend in parallel to each other.

The trench groove 505 described above may be formed using wet etching. For example, there is a method of etching a silicon substrate using a KOH solution, the etching rate is different depending on the crystallographic orientation (orientation) of the silicon may be used. A silicon wafer having a main surface in the <100> direction may be etched at a constant angle of 54.7 degrees using a KOH etching solution to form a V-shaped groove or a truncated inverted pyramid groove. 21 is a SEM photograph showing the structure of the V-shaped groove (FIG. 21 (a)) and the truncated inverted pyramid type groove (FIG. 21 (b)) formed through wet etching using a KOH solution. Depending on the sol of the wet etching time, it is possible to form a V-shaped groove having a pointed bottom as shown in FIG. 21 (a), or a truncated inverted pyramid-shaped groove having a flat bottom as shown in 21 (b). The wet etching of such a silicon substrate can be very easily formed in the trench grooves of the V-shape or truncated inverted pyramidal shape having the same shape without being sensitive to the change of conditions.

As such, the three-dimensional structure in which the trench grooves 505 are formed in the substrate 501 may be formed. Next, referring to FIG. 8, the solution in which the nanowires 10 are dispersed is provided in a three-dimensional structure in which the trench grooves 505 are formed. For example, a solution in which the nanowires 10 are dispersed may be dropped into the trench grooves 505 or sprayed into the trench grooves 505. Then, when the solution provided in the trench grooves 505 is dried, the nanowires 10 are aligned with the bottoms of the plurality of trench grooves 505 while the nanowires 10 are aligned with the lower groove valley portions by the inclined groove inner walls. This results in an ordered nanowire network with the desired orientation and pattern.

FIG. 22 is an SEM image showing nanowires aligned in the V-shaped trench grooves of a silicon substrate using the process described above. As shown in FIG. 22, the nanowires are well aligned in the trench grooves. In order to obtain the nanowire alignment shown in Figure 22, it was first put in a solvent such as isopropyl alcohol (isopropyl alcohol) to make a solution obtained by sonication (sonication) well dispersed (nano wire dispersed solution). This solution was then sprayed onto the V-shaped trench groove structure of the silicon substrate and dried sufficiently to obtain well aligned nanowires as shown in FIG.

Nanowire Sorting frame  making

In the above-described embodiment, a three-dimensional structure in which a trench groove is formed in the substrate itself is formed, but a trench groove for nanowire alignment may be provided by disposing a three-dimensional frame manufactured separately from the substrate on the substrate. 9 is a cross-sectional view of a three-dimensional framework that may be used for nanowire alignment in accordance with an embodiment of the invention, and FIG. 10 is a top view of the three-dimensional framework shown in FIG. 9. FIG. 9 is a cross-sectional view taken along the AA ′ line of the three-dimensional frame of FIG. 10. This three-dimensional framework serves as a 'three-dimensional structure with trench grooves'.

9 and 10, at least one trench groove 50 is formed on an upper surface of the three-dimensional mold 551 for nanowire alignment. In addition, an opening 15 extending along the longitudinal direction of the trench groove 50 is drilled in the bottom portion of the trench groove 50 of the three-dimensional mold 551. As the trench grooves 50 have deeper grooves, the inner walls of both grooves are inclined so that the width of the trench grooves becomes narrower. For example, the trench groove 50 may be a V-shaped groove or may have a cross-sectional shape of truncated inverted pyramid. The three-dimensional frame 551 for aligning the nanowires may be formed of a polymer material such as, for example, PDMS.

11-14 illustrate an example of a method of aligning nanowires on a substrate (eg, a silicon substrate) using the three-dimensional framework 551 for nanowire alignment described above. As shown in FIG. 11, a three-dimensional frame 551 for nanowire alignment is disposed on a substrate 601 that requires nanowire alignment. In this case, the three-dimensional mold 551 is disposed on the substrate 601 such that the upper surface of the substrate 601 is exposed through the opening 15 formed in the bottom portion of the trench groove 50 of the three-dimensional mold 551. . Then, as shown in FIG. 12, the solution 60 in which the nanowires 10 are dispersed is dropped or sprinkled on the three-dimensional mold 551 in which the trench grooves 50 are formed. Then, when the dropped or sprinkled solution 60 is dried, as shown in FIGS. 13 and 14, the liquid 60 dries, and the nanowire 10 descends to the bottom of the trench groove 50 to form the trench groove 50. Aligned along the longitudinal direction of the), you can get a well-ordered nanowire pattern. In particular, since the bottom of the trench groove 50 is drilled through the opening 15 as described above, the nanowire 10 aligned in the trench groove 50 may directly contact the substrate 601, and the nanowire alignment After this is completed, the aligned nanowires 10 remain on the substrate 601 even if the three-dimensional mold 551 is peeled off. In consideration of this point, the three-dimensional framework 551 may be repeatedly reused while moving from the substrate to the substrate as described below.

As described above, the nanowire alignment method using a three-dimensional structure (a three-dimensional frame formed and disposed separately from a part of the substrate itself or a substrate formed with a trench groove) is usefully applied in the fabrication of nanowire network devices, and is well aligned. A nanowire network device having nanowires can be obtained. Such a nanowire network device has improved performance compared to a conventional nanowire network device using a randomly arranged nanowire. In addition, using the above-described nanowire alignment method, the mass production is possible and the process is relatively simple, and at the same time, it significantly overcomes the disadvantages of the conventional nanowire network device, which is relatively inferior to a single nanowire device, and thus has high performance. The device can be implemented.

15 to 18 are views for explaining the method of manufacturing the three-dimensional mold 551 described above. Referring to FIG. 15, after preparing the mother substrate 701 having a planar shape, a trench groove 705 is formed by etching the upper surface of the mother substrate 701. As the mother substrate 701, for example, a silicon substrate can be used. In the trench grooves 705, both inner walls of the grooves are inclined so that the width of the trench narrows as the depth in the grooves increases. For example, a trench groove 705 having a cross-sectional shape of a V-shaped or truncated inverted pyramid may be formed. When the silicon substrate is used as the mother substrate 701, the trench grooves 705 may be formed using wet etching or other dry etching using, for example, KOH.

Next, referring to FIG. 16, a first polymer material is coated on the mother substrate 701 on which the trench grooves are formed to form a polymer layer 715 that completely fills the trench grooves. For example, an uncured polymer liquid material (eg, PDMS) may be coated in an amount sufficient to fill the trench grooves 705 of the mother substrate 701. By curing this coated polymer liquid material to a solid, a polymer layer 715 as shown in FIG. 16 can be obtained. Accordingly, the shape of the trench grooves 705 of the mother substrate 701 is transferred to the polymer layer 715 so that the polymer layer 715 has a cross-sectional shape of a pyramid. This polymer layer 715 is provided as a kind of mold for manufacturing the three-dimensional mold 551.

Next, referring to FIG. 17, the polymer layer 715 is peeled off from the mother substrate 701, and then the thin film 320 for layer separation is formed on the trench groove transfer surface (separation surface) of the pollimer layer 715. do. For example, a material such as parylene may be evenly coated on the separation surface of the polymer layer 715 to form a thin film 320 for separating layers. As described below, the thin film 320 for separating layers is used to easily separate the polymer material (second polymer material) to be formed thereon and the polymer layer 715 below.

Thereafter, as shown in FIG. 18, the second polymer material is coated on the layer separation thin film 320 to form a three-dimensional mold 551. As the second polymer material to be the three-dimensional mold 551, the same polymer material as the first polymer material for forming the polymer layer 715 may be used. For example, a three-dimensional mold 551 may be formed by coating a polymer liquid such as uncured PDMS on the thin film for separation of layers 320.

This three-dimensional framework 551 is separated from the polymer layer 715 and placed on a substrate that requires nanowire alignment. The three-dimensional mold 551 manufactured by the above-described process has a trench groove 50 as described with reference to FIGS. 9 and 10. That is, the trench groove 50 is inclined at both inner walls of the groove so that the width of the groove becomes narrower as the depth in the groove becomes deeper, and the bottom portion of the trench groove 50 is bored as an opening 15. The three-dimensional framework 551 may be moved to a substrate to form a nanowire network and used to align the nanowires on the substrate.

In order to form the opening 15 in the three-dimensional mold 551, as shown in FIG. 18, the valley portion of the polymer layer 715 is formed when the second polymer material is coated to form the three-dimensional mold 551. The second polymer material may be coated to leave some acid tip without filling up completely. Alternatively, after the valley portion of the polymer layer 715 is completely buried, the upper portion may be etched to leave a little acid portion of the polymer layer 715. When the three-dimensional mold 551 is removed from the polymer layer 715, trench grooves (refer to reference numeral 50 in FIG. 9), such as V-shaped or truncated inverted pyramid type, appear in the three-dimensional mold 551. An opening 15 having a width in nano units appears at the bottom of the groove 50.

The three-dimensional frame 551 for aligning the nanowires may be repeatedly reused while moving the substrate. As shown in FIG. 19, a three-dimensional frame 551 may be disposed on the substrate 601 to align the nanowires 10 on the substrate 601. Then, the three-dimensional mold 551 is peeled off from the substrate 601, and then placed on another substrate (another substrate requiring nanowire alignment) 801 and the above-described nanowire alignment process (see FIGS. 11 to 14). However, the nanowires may be aligned on the substrate 801 through the substrate changed from 601 to 801. Therefore, when performing nanowire alignment on several substrates, there is an advantage that can be repeated, reused by manufacturing a single three-dimensional framework.

The present invention is not limited by the above-described embodiment and the accompanying drawings. It is intended that the scope of the invention be defined by the appended claims, and that various forms of substitution, modification, and alteration are possible without departing from the spirit of the invention as set forth in the claims. Will be self-explanatory.

Embodiments of the present invention can be effectively applied to mass production of nanowire devices or nanowire network devices having well aligned nanowires at low cost.

By applying the aligned nanowire transfer method according to an embodiment of the present invention to nanowire transfer to a flexible substrate, it can be effectively used for fabricating flexible electronics.

Claims (26)

1. Aligning nanowires in the grooves of the first substrate having grooves on the top surface; And

   And transferring the nanowires aligned in the grooves of the first substrate to another second substrate by using a transfer member having elasticity and adhesion.
2. The method of claim 1,

   Separating the nanowires located on the upper surface of the first substrate outside the groove by using a removing member having an adhesive force between aligning the nanowires and transferring the aligned nanowires to the second substrate. Aligned nanowire transfer method characterized in that it further comprises.
3. The method of claim 2,

   Before the step of transferring the aligned nanowires to the second substrate, the step of aligning the nanowires and the step of removing the nanowires located on the upper surface of the first substrate outside the groove, it is further carried out by repeating Aligned nanowire transcription method.
4. The method of claim 1,

   Aligning the nanowires,

   Preparing a first substrate having a groove on an upper surface thereof;

   Providing a nanowire dispersion solution on a three-dimensional structure of the first substrate; And

   And drying the nanowire dispersion solution provided on the three-dimensional structure to align the nanowires in the grooves of the first substrate.
5. The method of claim 1,

   The groove is aligned nanowire transfer method, characterized in that it comprises a trench-shaped groove extending in one direction.
6. The method of claim 1,

   The grooves are aligned nanowire transfer method, characterized in that the groove has a shape inclined both sidewalls of the grooves become narrower as the depth in the grooves.
7. The method of claim 1,

   Cross-sectional shape of the groove is aligned nanowire transfer method, characterized in that the V-shaped or trapezoidal shape.
8. The method of claim 1,

   And a plurality of grooves formed on the first substrate.
9. The method of claim 2,

   And the removing member has elastic force together with adhesive force.
10. The method of claim 1,

    And said transfer member is formed of PDMS.
11. The method of claim 2,

    And the removal member is formed of PDMS.
12. Preparing a substrate having a three-dimensional structure in which trench grooves in which both inner walls of the groove are inclined are formed so that the width in the groove becomes narrower as the depth in the groove becomes deeper;

    Providing a solution in which nanowires are dispersed on the three-dimensional structure; And

    Drying the solution provided on the three-dimensional structure to align the nanowires in the trench grooves along a length direction of the trench grooves.
13. The method of claim 12,

    And a plurality of trench grooves formed in the three-dimensional structure, and the plurality of trench grooves extend in parallel to each other.
14. The method of claim 12,

    Cross-sectional shape of the trench groove is V-shaped or nanowire alignment method characterized in that the cross-sectional shape of the truncated inverted pyramid.
15. The method of claim 12,

    Preparing the substrate having the three-dimensional structure,

    Preparing a mother substrate having a planar top surface; And

    Etching the upper surface of the mother substrate to form trench grooves in which both inner walls of the groove are inclined so that the width of the groove becomes narrower as the depth in the groove becomes deeper. .
16. The method of claim 15,

    The mother substrate is a nanowire alignment method, characterized in that the silicon substrate.
17. The method of claim 12,

    Preparing the substrate having the three-dimensional structure,

    Preparing a mother substrate having a planar top surface;

    Etching the upper surface of the mother substrate to form trench grooves in which both inner walls of the groove are inclined so that the width of the groove becomes narrower as the depth in the groove becomes deeper;

    Coating a first polymer material on the mother substrate where the trench grooves are formed to form a polymer layer which completely fills the trench grooves;

    After separating the polymer layer from the mother substrate and coating a second polymer material on the separation surface of the polymer layer, trench grooves in which both inner walls of the grooves are inclined so that the width in the grooves becomes narrower as the depth in the grooves becomes deeper. Forming a three-dimensional mold which is formed and has a bottom portion of the trench groove opened as an opening; And

    Separating the three-dimensional framework from the polymer layer and placing it on a substrate that requires nanowire alignment.
18. The method of claim 17,

    The preparing of the substrate having the three-dimensional structure may include: separating the polymer layer from the mother substrate and then separating the polymer layer on the separation surface of the polymer layer before coating the second polymer material on the separation surface of the polymer layer. Nanowire alignment method further comprising the step of forming a thin film for layer separation.
19. The method of claim 17,

    After the step of aligning the nanowires in the trench grooves, separating the three-dimensional framework from the substrate and disposing the three-dimensional framework on another substrate that requires nanowire alignment to reuse the three-dimensional framework. Nanowire alignment method.
20. A framework for aligning nanowires by placing them on a substrate on which nanowires are to be arranged

    Trench grooves are formed on the opposite side of the surface disposed on the substrate, and both sides of the trench grooves are inclined so that the trench grooves become narrower as the depth of the grooves increases. Three-dimensional framework for aligning nanowires, characterized in that perforated.
21. The three-dimensional mold of claim 20, wherein the plurality of trench grooves are formed in the three-dimensional mold, and the plurality of trench grooves extend in parallel to each other.
22. The three-dimensional framework of claim 20, wherein the trench groove has a cross-sectional shape of V-shaped or truncated inverted pyramid.
23. Preparing a mother substrate having a planar top surface;

    Etching the upper surface of the mother substrate to form trench grooves in which both inner walls of the groove are inclined so that the width of the groove becomes narrower as the depth in the groove becomes deeper;

    Coating a first polymer material on the mother substrate where the trench grooves are formed to form a polymer layer which completely fills the trench grooves; And

    After separating the polymer layer from the mother substrate and coating a second polymer material on the pyramid structure formed on the upper surface of the polymer layer, both inner walls of the groove are inclined so that the width in the groove becomes narrower as the depth deeper in the groove And forming a three-dimensional mold in which a trench groove is formed and a bottom portion of the trench groove is opened as an opening.
24. A substrate having a groove that becomes narrower in width; And

    An electronic device comprising nanowires aligned in the grooves.
25. The method of claim 24,

    The substrate is an electronic device, characterized in that the flexible substrate.
26. The method of claim 24 or 25,

    The groove is cross-sectional shape is an electronic device, characterized in that the V-shaped, trapezoidal or truncated inverted pyramid form.

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