WO2016108334A1

WO2016108334A1 - Polarized carbon nanotube light emitting device and integrated circuit thereof

Info

Publication number: WO2016108334A1
Application number: PCT/KR2015/001240
Authority: WO
Inventors: 김상훈; 김나영
Original assignee: 김상훈
Priority date: 2015-01-02
Filing date: 2015-02-06
Publication date: 2016-07-07
Also published as: KR101592547B1

Abstract

A carbon nanotube light emitting device according to the present invention comprises: a substrate; a buffer layer provided on the substrate; a carbon nanotube layer provided on the buffer layer; a first nano electrode connected to the carbon nanotube layer; and a second nano electrode connected to the carbon nano tube layer, wherein the distance between the first nano electrode and the second nano electrode is 5 to 40 nm.

Description

Polarized carbon nanotube light emitting device and its integrated circuit

The present invention relates to a carbon nanotube light emitting device, and more particularly to a light emitting device of carbon nanotubes using a plasmon effect (Plasmonic effect) on the two electrodes providing electrons and holes.

Although carbon nanotubes (CNT) have been actively researched since light emission was observed by photoluminescence measurement, which observed light emission by light excitation, recently, light emitting devices have been observed in that light emission by current injection has been observed. It is expected as.

Carbon nanotubes (CNTs) refer to hollow, one-dimensional cylindrical materials made up of carbon atoms. The hexagons made up of six carbon atoms, the basic structure of carbon nanotubes, are connected to form a cylinder. The diameter of the carbon nanotubes is approximately 1-5 nm and the length can be as short as 10 nm to as long as 1 mm. At this time, the diameter of the cylinder and the direction of the cylinder determine the electrical properties of the conductor or semiconductor of the carbon nanotubes.

The electrical properties of carbon nanotubes have metallic or semiconducting properties as a function of their diameter and chirality. In general, SWNTs are known to have a semiconductivity in which 1/3 is metallic and the remaining 2/3 is band gap inversely proportional to the diameter of carbon nanotubes.

Carbon nanotubes with the properties of semiconductors have excellent optical properties as well as excellent electrical properties. Carbon nanotubes are direct bandgap materials that emit light when electrons and holes merge.

Light emission by recombination of electrons and holes excites electrons and holes by any method in semiconductor carbon nanotubes, and causes light emission by recombination of these.

As the excitation method, (i) electron and hole injection excitation, (ii) collision excitation, and (iii) heating excitation are reported. In (i), electrons and holes are injected from opposite directions in two electrodes formed on carbon nanotubes, and light is emitted by recombination thereof. (ii) injects holes (or electrons) having high kinetic energy from the electrode, generates electrons and hole pairs (exciter) with energy when the kinetic energy is lost, and emits light by relaxation of excitons. In (iii), electrons are excited by thermal energy by heating by joule heat or the like when the carbon nanotubes are energized, and emit light when electrons relax with holes.

However, at present, there is a problem of practical use because the intensity of light emitted from the carbon nanotube light emitting device made by the electrical method is not large.

An object of the present invention is to apply a plasmonic effect to two electrodes providing electrons and holes to minimize light footprint and to realize a light emitting integrated circuit, and to adjust the direction of the electrode and carbon nanotubes to polarize the light. It provides a carbon nanotube light emitting device that localizes linearly polarized light to increase light intensity and optimize an integration density per unit area.

An embodiment according to one aspect of the invention,

Carbon nanotube layer;

A first nano electrode connected to the carbon nanotube layer in one region; And

A second nano electrode connected to the carbon nanotube layer in another region;

The gap between the first nano electrode and the second nano electrode provides a polarized carbon nanotube light emitting device having a 5 to 40 nm.

In this case, the first nano-electrode and the second nano-electrode may each have a triangular shape, and the vertices of the triangles may be provided to face each other.

In addition, the arrangement angle between the direction of the axis of the carbon nanotube layer and the dipole direction of the first nano electrode and the second nano electrode is preferably in the range of -10 to 10 degrees.

In this case, the first nano-electrode and the second nano-electrode provide electrons and holes and simultaneously generate plasmon.

In addition, the carbon nanotubes of the carbon nanotube layer may be a single wall carbon nanotube (SWNT) or a single wall carbon nanotube (SWNT) nanobelt.

Another embodiment of the present invention

A carbon nanotube light emitting device comprising a carbon nanotube layer connected to a first electrode and a second electrode,

Between the first electrode and the second electrode,

A first nano electrode connected to the carbon nanotube layer in one region;

And a distance between the first nano electrode and the second nano electrode is 5 to 40 nm.

According to another aspect of the invention,

At least one carbon nanotube line;

A first nanoelectrode line connected to one region intersecting the carbon nanotube line and having a first nanoelectrode at an intersection region;

It is connected to the other region intersecting the carbon nanotube line, the cross region includes a second nano electrode line having a second nano electrode,

A gap between the first nano electrode and the second nano electrode provides a polarized carbon nanotube light emitting device integrated circuit having a thickness of 5 to 40 nm.

In this case, the first nano electrode line is connected to the first common electrode, and the second nano electrode line is connected to the second common electrode.

The second nanoelectrode line may be any nanoelectrode line adjacent to the first nanoelectrode line.

Another embodiment of the present invention

At least one first carbon nanotube line;

At least one second carbon nanotube line arranged to intersect with the first carbon nanotube line;

In this case, the second nano electrode line may be any nano electrode line adjacent to the first nano electrode line.

The carbon nanotube light emitting device according to the present invention filters the wavelengths of the light emitting device by adjusting the shape, size, and gap length of the nanoelectrode, thereby making it possible to produce a light emitting device having high definition and high definition color. have.

It is possible to optimize the density of the carbon nanotube light emitting device per unit area by setting the footprint of the light emitting area of the carbon nanotube to 100 nm 2 or less.

By connecting in a multi-dimensional parallel structure, all the devices emit light by applying voltage to the common electrodes, thereby maximizing power efficiency and output luminance.

In addition, the light emitting device can be manufactured with a light emitting device having an ultra-fine structure having an effective light emitting area of 100 to 2,500 nm 2.

In addition, the present invention shows a light emitting device integrated circuit structure of the integrated density per unit area optimized.

The light emitting device and the light emitting device integrated circuit structure according to the present invention can be applied to various technologies such as LCD backlighting, high-contrast imaging, optical communications.

1 is a cross-sectional view of a carbon nanotube light emitting device according to an aspect of the present invention.

2 is an explanatory view showing various embodiments of a nano electrode of a carbon nanotube light emitting device according to an embodiment of the present invention.

3 is an explanatory diagram of a carbon nanotube light emitting device according to an embodiment of the present invention.

4 is an explanatory diagram of a plasmon effect of a carbon nanotube light emitting device according to an embodiment of the present invention.

5 is a plan view showing a structure in which an electrode is connected to a carbon nanotube light emitting device according to an embodiment of the present invention.

6 is a plan view of a carbon nanotube light emitting device according to an aspect of the present invention.

7 is an exemplary view of a carbon nanotube light emitting device integrated circuit according to another aspect of the present invention.

8 is another exemplary view of an integrated circuit of a carbon nanotube light emitting device according to another aspect of the present invention.

Prior to describing the present invention in detail below, it is understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of the invention, which is limited only by the scope of the appended claims. shall. All technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art unless otherwise indicated.

Throughout this specification and claims, unless stated otherwise, the term “comprise, comprising, comprising” means to include the referenced article, step, or group of articles, and step, and any other It is not intended to exclude any object, step, or group of things or group of steps.

On the other hand, various embodiments of the present invention can be combined with any other embodiment unless clearly indicated to the contrary. In particular, any feature indicated as being preferred or advantageous may be combined with any other feature and features indicated as being preferred or advantageous.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a cross-sectional view of a carbon nanotube light emitting device according to an embodiment of the present invention, Figure 2 is a plan view of a carbon nanotube light emitting device according to an embodiment of the present invention, Figure 3 is a carbon according to an embodiment of the present invention 4 is an explanatory view of a plasmon effect of a carbon nanotube light emitting device according to an embodiment of the present invention, Figure 5 is a plan view showing a structure in which an electrode is connected to the carbon nanotube light emitting device. Accordingly, the carbon nanotube light emitting device includes a substrate 10, a buffer layer 20, a first nanoelectrode 30, a carbon nanotube layer 50, and a second nanoelectrode 40.

The material of the substrate 10 is not limited, and for example, Si, SiO 2, Al 2 O 3, MgO, or the like may be used. In particular, heavily-doped silicon wafers or quartz may be used. Flexible substrates are also possible.

As long as the first nanoelectrode 30 and the second nanoelectrode 40 are not electrically shorted, any substrate may be used. The 20 provided on the substrate may use, for example, SiO 2 or hafnium oxide (HfO 2), which is a high-k dielectric gate material.

The first and

second nano electrodes

30 and 40 are formed on the buffer layer, and the length of one side of the electrode is patterned to silver nanoscale. Typically, the first nano-electrode 30 provides electrons, the second nano-electrode 40 provides holes, and the shape of the nano-electrodes causes a plasmon effect as shown in FIG. It may be formed into an elongated, rectangular shape, but triangles are advantageous for focusing light in local space.

It is preferable that the thickness of the first nanoelectrode 30 and the second nanoelectrode 40 is 20 to 40 nm, and the length of one side of the nanoelectrode is 25 to 100 nm.

In addition, the interval d between the first nanoelectrode 30 and the second nanoelectrode 40 facing each other is 5 to 40 nm, more preferably 5 to 20 nm so that light is localized between the intervals. . Electrodes with a spacing of less than 5 nm are at risk of sticking to two gaps in the manufacturing process (for example, the current e-beam process), and when the gap exceeds 40 nm, it is difficult to expect the effect of light accumulation through the plasmon effect. . That is, by optimizing the spacing between the two electrodes to 5-40 nm, the plasmon effect is induced through the shape of a bowtie that maximizes the antenna effect.

The plasmon effect is a phenomenon in which light is integrated on a metal surface, and an embodiment of the present invention applies such a plasmon effect. In other words, by using the nano-scale electrode to generate the excitons, which are the basis of the light emitting device, the effect of increasing the electromagnetic field in the nano-gap of the two electrodes. When the two nanoelectrode gaps are 10-40 nm, the integration effect is apparent as the electromagnetic field is spatially localized. Therefore, by combining this phenomenon with the light emitting device, the intensity of light generated in the carbon nanotube light emitting device is increased.

On the other hand, in order to maximize the plasmon effect, it is preferable that the dipole direction of the first nano electrode 30 and the second nano electrode 40 coincides with the direction of the polarization (arrow direction) generated in the carbon nanotube layer. .

Charges are attracted to the pointed portions of the two metal electrodes that face each other. In this case, polarity oscillates periodically with time. For example, when the first nano-electrode 30 is + and the second nano-electrode 40 is-, and when the half period has passed, the first nano-electrode 30 is-, the second nano-electrode. The electrode 40 becomes positive. Therefore, both ends can be described as a dipole and this direction is called a dipole direction.

In addition, since light emitted from the carbon nanotubes is linearly polarized along the axis of the carbon nanotubes, this is called a direction of polarization generated from the carbon nanotubes.

The plasmon effect can be measured by the cosine value in the dipole direction and the polarization direction. As illustrated in FIG. 4, the alignment angle, which is the difference between the angle θ in the dipole direction and the polarization direction, is -10 to 10 degrees, and preferably 0 degrees. Parallel to the dipole direction of the nanoelectrode, polarized light is further increased

Therefore, when the arrangement angle of the nano-electrode and the carbon nanotubes is 0 degrees, it is most preferable to achieve light emission of polarized light. This is because the light emitted from the carbon nanotubes is linearly polarized along the axis of the tube, so that the light is parallel to the dipole direction of the nanoelectrode, thereby further increasing the polarized light.

As the metal forming the nanoelectrode, Ti, Au, Pd, or the like may be preferably used. In order to provide electrons and holes to the carbon nanotube layer 50, the first nanoelectrode 30 and the second nanoelectrode 40 use metals having different work functions. For example, the material of the electrode 30 is preferably Ti having a large work function, but the material of the other electrode 40 is Au having a small work function.

The carbon nanotubes used for the carbon nanotube layer 50 are electrically connected to the first nanoelectrode 30 and the second nanoelectrode 40 to receive electrons and holes, and also to form plasma between the nanoelectrodes. The phenomenon causes light emission.

The type of carbon nanotubes is not limited, but SWNT is preferably used. The wavelength of the generated light is determined by the diameter of the carbon nanotubes and the direction of the cylinder. The wavelength range of the light generated from the carbon nanotubes is 400 nm to 2 μm, ranging from the visible region to the infrared region.

At this time, the wavelength of the light is determined by adjusting the diameter of the carbon nanotubes. For example, (4,3) -SWNTs have a diameter of 0.483 nm, and 398 nm and 700 nm light have 0.521 nm diameter and (6,1) -SWNTs have 632 nm and 653 nm light, 0.703 nm diameter. The (7,3) -SWNT can emit 505 nm and 992 nm light, while the 1.307 nm diameter (10,9) -SWNT can emit 1556 nm light.

As the carbon nanotube thin film, carbon nanotubes by a growth method such as chemical vapor deposition can be used.

The carbon nanotube layer 50 used as the light emitting element of the first embodiment may be in contact with the substrate 20, or may be a cross-linked carbon nanotube having both ends of the carbon nanotube supported on the substrate. The carbon nanotubes may be exposed to the atmosphere, or may be carbon nanotubes covered with insulator materials such as SiO 2 or glass or sapphire.

However, since the carbon nanotubes are damaged by reaction with oxygen in the atmosphere, it is preferable that the carbon nanotubes are covered with an insulator material or maintained in vacuum to prevent damage to the carbon nanotubes by reaction with oxygen. Do.

Meanwhile, referring to FIG. 5, the first nanoelectrode 30 and the second nanoelectrode 40 are connected to the first common electrode 31 and the second common electrode 41 by connecting

lines

32 and 42, respectively. do.

The width of the connecting

lines

32 and 42 is 10-20 nm, and the length may be short or long depending on the design, but it is preferably 100 nm-1 μm.

6 is a plan view of a carbon nanotube light emitting device according to another aspect of the present invention. This is a carbon nanotube light emitting device having a structure in which a plasmon phenomenon is generated by separately providing a nanoelectrode in addition to an electrode providing an electrode and holes in a conventional carbon nanotube light emitting device.

The carbon nanotube light emitting device having a structure that does not generate a plasmon shape in the related art is a structure in which the first electrode 3, the second electrode 4, and the carbon nanotube layer are electrically connected, and each electrode has a thickness of approximately 500 nm to 2 μm. It has a gap between electrodes.

Accordingly, the first nanoelectrode 30 and the second nanoelectrode 40, which may cause a plasmon phenomenon between the first electrode 3 and the second electrode 4, have an arrangement angle of 0 with the carbon nanotube layer. It can be further arranged to be connected to.

That is, the first electrode 3 and the second electrode 4 electrically connected to the carbon nanotube layer 50, and between the first electrode 3 and the second electrode 4 separately from the carbon nanotubes. The first nanoelectrode 30 and the second nanoelectrode 40 are electrically connected to each other.

In this case, the plasmon phenomenon may be controlled by applying a voltage to the first nanoelectrode 30 and the second nanoelectrode 40. Unexplained reference numerals 51 and 52 are cavity electrodes for supplying voltage to the nanoelectrodes.

Accordingly, a plurality of rows of carbon nanotube lines 500 forming a carbon nanotube layer in individual light emitting devices are formed, and the carbon nanotube lines 500 intersect the

nanoelectrode lines

300 and 400. In addition,

nano electrodes

30 and 40 are formed in an intersection region of the carbon nanotube lines 500 of the

nano electrode lines

300 and 400. The

nano electrodes

30 and 40 are connected to the

column connection lines

32 and 42, and the connection lines 32 and 42 are connected to the

cavity electrodes

31 and 41. At this time, the first nano electrode 30 and the second nano electrode 40 adjacent to each other are arranged to cause light emission by the plasmon effect in both directions.

In this case, in order to easily form the

nanoelectrodes

30 and 40 and to be efficiently connected to the cavity electrodes, it is preferable that the two nanoelectrodes of the same polarity are formed in a combined shape with each other. This allows each nanoelectrode to act in both directions.

8 is another exemplary view of an integrated circuit of a carbon nanotube light emitting device according to another aspect of the present invention. Accordingly, the

carbon nanotube lines

500 and 501 are arranged in a plurality of rows and a plurality of columns, and the

carbon nanotube lines

500 and 501 cross the

nano electrode lines

301 and 401. In addition,

nano electrodes

30 and 40 are formed at intersections of the

carbon nanotube lines

500 and 501 of the

nano electrode lines

301 and 401. The

nano electrodes

30 and 40 are connected by a plurality of oblique direction connection lines 32 and 42, and the connection line is connected to the common electrode.

At this time, the first nano electrode 30 and the second nano electrode 40 are arranged to cause light emission by the plasmon effect in each of the four directions. That is, each nanoelectrode emits light by causing a plasmon effect with adjacent nanoelectrodes in up, down, left, and right directions.

Hereinafter, a method of manufacturing a carbon nanotube light emitting device according to another aspect of the present invention.

A method of manufacturing a carbon nanotube light emitting device includes a substrate providing step, a carbon nanotube layer forming step, and a nanoelectrode forming step.

Substrate provision step is to provide a substrate, it is preferable that a buffer layer is provided on the substrate.

The carbon nanotube layer forming step is a step of forming a carbon nanotube layer on the buffer layer. One type of (n, m) -SWNT can be used, as well as SWNT nanobelts as well as a single strand of SWNT. In this case, the nano belt means a ribbon structure in which several SWNTs are collected.

When using one strand, a diameter of 0.4 to 1.5 nm and a length of 100 nm to 1 mm are used. In addition, when using SWNT nanobelt 1 to 20 nm in width, 100 to 1000 nm in length, 1 to 10 nm in height is possible.

Forming the carbon nanotube thin film on the substrate can be formed by applying a carbon nanotube dispersion solution obtained by dispersing carbon nanotubes in a solvent onto a substrate, or by various methods such as spin coating, inkjet printing, and chemical vapor deposition. It can form and ultimately grow one kind of carbon nanotubes directly.

In addition, it can be dispersed one by one using the tip of the atomic force microscopy (atomic force microscopy).

The nanoelectrode forming step is a step of forming a nanoelectrode on the buffer layer and carbon nanotubes. Since the nanoelectrode forms a very thin film, the nanoelectrode may be formed without empty space on the carbon nanotubes and the buffer layer.

The nanoelectrode may be formed by metal deposition after patterning using, but not limited to, E-beam lithography.

After the nanoelectrode is formed, annealing may be performed to increase the connection between the nanoelectrode and the carbon nanotube. The annealing temperature is adjusted depending on the metal used and preferably 200-800 ° C.

Features, structures, effects, and the like illustrated in the above-described embodiments may be combined or modified with respect to other embodiments by those skilled in the art to which the embodiments belong. Therefore, contents related to such combinations and modifications should be construed as being included in the scope of the present invention.

Claims

Carbon nanotube layer;

A first nano electrode connected to the carbon nanotube layer in one region; And

A second nano electrode connected to the carbon nanotube layer in another region;

The gap between the first nano electrode and the second nano electrode is 5 to 40 nm polarized carbon nanotube light emitting device.
The method of claim 1,

The first nano-electrode and the second nano-electrode have a triangular shape, respectively, and the vertex of the triangle is provided with a structure facing each other polarized carbon nanotube light emitting device.
The method of claim 2,

A polarization carbon nanotube light emitting device in which an arrangement angle between a direction of polarization generated in the carbon nanotube layer and a dipole direction of the first nano electrode and the second nano electrode is -10 to 10 degrees.
The method of claim 3,

The first nano-electrode and the second nano-electrode polarized carbon nanotube light emitting device for generating electrons and holes and at the same time generates a plasmon phenomenon.
The method of claim 4, wherein

The carbon nanotubes of the carbon nanotube layer are single-walled carbon nanotubes (SWNT) or single-walled carbon nanotubes (SWNT) nano belts (nanobelt) polarized carbon nanotube light emitting device.
A carbon nanotube light emitting device comprising a carbon nanotube layer connected to a first electrode and a second electrode,

Between the first electrode and the second electrode,

A first nano electrode connected to the carbon nanotube layer in one region;

A second nano electrode connected to the carbon nanotube layer in another region;

Includes, wherein the distance between the first nano electrode and the second nano electrode is 5 to 40 nm polarized carbon nanotube light emitting device.
Carbon nanotube layer;

A first nano electrode connected to the carbon nanotube layer in one region; And

A second nano electrode connected to the carbon nanotube layer in another region;

The distance between the first nano electrode and the second nano electrode is 5 to 40 nm,

And the first nano electrode is connected to the first common electrode by a connection line, and the second nano electrode is connected to the second common electrode by a connection line.
At least one carbon nanotube line;

A first nanoelectrode line connected to one region intersecting the carbon nanotube line and having a first nanoelectrode at an intersection region;

It is connected to the other region intersecting the carbon nanotube line, the cross region includes a second nano electrode line having a second nano electrode,

And a gap between the first nano electrode and the second nano electrode is 5 to 40 nm.
The method of claim 8,

And the first nano electrode line is connected to a first common electrode, and the second nano electrode line is connected to a second common electrode.
The method of claim 9,

And the second nanoelectrode line is an arbitrary nanoelectrode line adjacent to the first nanoelectrode line.
At least one first carbon nanotube line;

At least one second carbon nanotube line arranged to intersect with the first carbon nanotube line;

A first nanoelectrode line connected to one region intersecting the carbon nanotube line and having a first nanoelectrode at an intersection region;

It is connected to the other region intersecting the carbon nanotube line, the cross region includes a second nano electrode line having a second nano electrode,

And a gap between the first nano electrode and the second nano electrode is 5 to 40 nm.
The method of claim 11,

And the second nanoelectrode line is an arbitrary nanoelectrode line adjacent to the first nanoelectrode line.