KR101971328B1 - Organic light emitting transistor and manufacturing method thereof - Google Patents

Abstract

The present invention relates to an organic light emitting transistor and a method of manufacturing the organic light emitting transistor according to an embodiment of the present invention includes a substrate 10, hafnium oxide (HfO _X ), an insulating layer formed on the upper surface of the substrate 10 (30), a self-assembled layer 40, a pentacene compound, which includes n-dodecylphosphonic acid (PA-C12) and is formed on the insulating layer 30 (on); A hole transport layer 50 formed on the self-assembled layer 40, and 4- (dicyanomethylene) -2-methylene-6- (pi-dimethylaminostriyl 1) -4H-pyran Tris (8-hydroxyquinoline) aluminum (Alq ₃ ) doped with (4- (dicyanomethylene) -2-methyl-6- (p-dimethylaminostyryl) -4H-pyran, DCM) And a light emitting layer 60 formed on the hole transport layer 50.

Description

Organic light emitting transistor and its manufacturing method {ORGANIC LIGHT EMITTING TRANSISTOR AND MANUFACTURING METHOD THEREOF}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an organic light emitting transistor and a method of manufacturing the same, and more particularly, to an organic light emitting transistor and a method of manufacturing the same, which are driven at low voltage and have excellent field mobility in air.

Organic semiconductor electronic devices are one of the most advanced IT technologies that can provide application concepts that are completely different from existing inorganic semiconductor-based devices. Among organic semiconductors, organic light-emitting diodes (OLEDs) have gained popularity as high-quality displays, such as those employed in mobile phone main windows, small screens of various mobile devices, and TV screens.

    In general, a flat panel display panel is a device having a flat surface using visible light. When a strong voltage is applied between two electrodes, gas discharge occurs between the electrodes, and the ultraviolet rays generated at this time hit the phosphor. Plasma display panel (PDP) using light emitting phenomenon, electrons emitted from a flat cathode (Cathode) hits the phosphor and emits heat electrons by applying voltage to FED (electroluminescent display) and filament When the electrons are accelerated in the grid to reach the anode, the current flows through a thin film of VFD (fluorescent fluorescent display), fluorescent or phosphorescent organic material that displays information by colliding with the already patterned phosphor and emitting light. Organic light-emitting display panel (OLED), a liquid that emits light when electrons and holes combine in an organic material layer, LCD (liquid crystal display) that displays information using the principle that liquid crystal plays the role of shutter and transmits or blocks light according to voltage switching. ).

    On the other hand, as a driving method for driving an organic EL element, an active matrix type field effect transistor (FET) using a thin film transistor (TFT) is effective in terms of operation speed and power consumption. It is considered to be. On the other hand, the semiconductor materials constituting the thin film transistor have been studied for inorganic semiconductor materials such as silicon semiconductors and compound semiconductors, and in recent years, active research on organic thin film transistors (organic TFTs) using organic semiconductor materials have been actively conducted. . Organic semiconductor materials are expected as next-generation semiconductor materials, but have a problem of lower charge mobility and higher resistance than inorganic semiconductor materials.

    On the other hand, for field effect transistors, in a vertical FET structure having a vertical FET structure, the channel width of the transistor can be shortened, and the entire surface electrode can be effectively used. Since it can be utilized, advantages, such as being able to make high-speed response, large electric power, and an interface influence hard, are recognized. Therefore, in recent years, taking advantage of the above advantages of the electrostatic induction transistor (SIT), as disclosed in the patent document of the following prior art document, an organic light emitting transistor in which such an SIT structure and an organic EL element structure are combined has been developed.

Specifically, Organic Light-Emitting Field-effect Transistors (OLEFETs) are devices having both OLED and OTFT functions, and generally employ OTFT transverse conduction channel structures and recombine the same electrons and holes as OLEDs. Based on the light emitting mechanism of the present invention, it is useful in both basic research and development of technical applications of organic electronic materials and devices. Because OLEFETs exhibit luminescence in transverse channel structures, they can intuitively provide a very good evaluation system for studying physical processes such as charge carrier injection, transfer, and electroluminescence in organic semiconductors. In addition, since OLEFETs are highly integrated devices that can control luminescence, they can be applied to the development of active matrix full-color electroluminescent displays or variable organic laser devices. However, the conventional OLETET is driven at a high voltage to ensure a high capacitance, which makes it difficult to miniaturize the device. In addition, there is a problem in that the electric field mobility and the stability of the device in air.

Therefore, there is an urgent need for a solution for solving the problems of the conventional OLETET.

KR 10-2008-0082656 A

The present invention is to solve the above problems of the prior art, an aspect of the present invention is to use a dielectric layer having a high dielectric constant, and to form a hole transport layer and an electron transport layer with a specific compound thereon is driven at low voltage and in the air It is to provide an organic light emitting transistor having excellent field mobility and excellent mobility of holes and electrons.

An organic light emitting transistor according to the present invention comprises a substrate; An insulation layer including hafnium oxide (HfO _X ) and formed on an upper surface of the substrate; a self-assembled layer comprising n-dodecylphosphonic acid (PA-C12) and formed on the insulating layer (on); A hole transport layer comprising a pentacene compound and formed on the self-assembled layer; And 4- (dicyanomethylene) -2-methylene-6- (pi-dimethylaminostriyl1) -4H-pyran (4- (dicyanomethylene) -2-methyl-6- (p-dimethylaminostyryl) And a light emitting layer including tris (8-hydroxyquinoline) aluminum (Alq ₃ ) doped with -4H-pyran, DCM) and formed on the hole transport layer.

In addition, in the organic light emitting transistor according to the present invention, the doping concentration of the DCM is 0.5 ~ 1.0 mol%.

In addition, in the organic light emitting transistor according to the present invention, the hole transport layer has a thickness of 90 to 110 kPa.

In the organic light emitting transistor according to the present invention, the thickness of the light emitting layer is 390 to 410.

In addition, in the organic light emitting transistor according to the present invention, N, N'-ditridecyl perylene-3,4,9,10-tetracarboxylic diimide (N, N'-ditridecylperylene-3,4,9) And an 10-tetracarboxylic diimide) compound, and an electron transport layer formed on the light emitting layer.

 In the organic light emitting transistor according to the present invention, the electron transport layer has a thickness of 290 to 310 mW.

In addition, the organic light emitting transistor according to the present invention is disposed on the electron transport layer to face each other at intervals of 200 μm, and each of the source electrode and the drain electrode having a length of 10 mm;

On the other hand, the method of manufacturing an organic light emitting transistor according to the present invention comprises the steps of A) forming a gate electrode on the lower surface of the substrate; B) depositing hafnium oxide (HfO _X ) on the upper surface of the substrate to form an insulating layer; C) immersing the substrate in a solution of n-dodecylphosphonic acid (PA-C12) dissolved in ethanol to form a self-assembled layer on the insulating layer; D) inserting said substrate into a cluster beam deposition chamber; E) depositing a hole transport layer on the self-assembly layer by vaporizing by putting a pentacene compound inside a first crucible and heating it, and supplying it inside the cluster beam deposition chamber; F) A tris (8-hydroxyquinoline) aluminum (Alq ₃ ) compound was placed in a second crucible, and 4- (dicyanomethylene) -2-methylene was placed in a third crucible. -6- (Py-dimethylaminostriyl 1) -4 H-pyran (4- (dicyanomethylene) -2-methyl-6- (p-dimethylaminostyryl) -4H-pyran, DCM) compound, and then each Vaporizing by heating to deposit a light emitting layer on the electron transport layer by supplying each into the cluster beam deposition chamber; G) N, N'-ditridecylperylene-3,4,9,10-tetracarboxylic diimide (N, N'-ditridecylperylene-3,4,9,10-tetracarboxylic diimide in the fourth crucible Depositing an electron transport layer on the light emitting layer by vaporizing the compound by heating and supplying the compound to the inside of the cluster beam deposition chamber; And H) forming a drain electrode and a source electrode on the electron transport layer.

Further, in the method of manufacturing an organic light emitting transistor according to the present invention, the temperature of the first crucible is 220 ~ 250 ℃, the temperature of the second crucible is 330 ~ 350 ℃, the temperature of the fourth crucible is 270 ~ 300 ° C.

In addition, in the organic light emitting transistor according to the present invention, the deposition rate of the hole transport layer is 0.5 ~ 1.0 Å / s, the deposition rate of the light emitting layer is 0.1 ~ 0.3 Å / s, the deposition rate of the electron transport layer is 1.0 ~ 2.0 mW / s.

Further, in the organic light emitting transistor according to the present invention, each of the first crucible, the second crucible, the third crucible, and the fourth crucible has a nozzle for supplying a vaporized compound into the cluster beam deposition chamber, The diameter of the nozzle is from 0.5 to 1.5 mm.

In the organic light emitting transistor according to the present invention, each of the first crucible, the second crucible, the third crucible, and the fourth crucible is heated by a voltage application method, and the first crucible has a voltage of 6 to 8 V. Then, a voltage of 10 to 12 V is applied to the second and third crucibles, and a voltage of 7 to 9.5 V is applied to the fourth crucible.

The features and advantages of the present invention will become more apparent from the following detailed description based on the accompanying drawings.

Prior to this, the terms or words used in this specification and claims are not to be interpreted in a conventional and dictionary sense, and the inventors may appropriately define the concept of terms in order to best explain their invention in the best way possible. It should be interpreted as meaning and concept corresponding to the technical idea of the present invention based on the principle that the present invention.

According to the present invention, it is possible to drive at a low voltage by using an insulating layer having a high dielectric constant, the light emitting layer is disposed between the hole transport layer and the electron transport layer to increase the luminous efficiency.

In addition, by depositing the electron transport layer and the hole transport layer with a predetermined compound, the electric field mobility in the air and the stability of the device is improved. Accordingly, the present invention can provide a motif that can be easily developed a drive circuit in the future.

1 is a cross-sectional view of an organic light emitting transistor according to an embodiment of the present invention.
2 is a plan view of an organic light emitting transistor according to an exemplary embodiment of the present invention.
3 is a perspective view illustrating an operating principle of an organic light emitting transistor according to an exemplary embodiment of the present invention.
4 is a cross-sectional view of a vaporization apparatus for manufacturing an organic light emitting transistor according to an embodiment of the present invention.
5 is an image photographing the emission of the organic light emitting transistor according to an embodiment of the present invention with a CCD camera.
6A is a graph showing the capacitance of the organic light emitting transistor according to the embodiment of the present invention, and FIG. 6B is a graph showing the leakage current of the organic light emitting transistor according to the embodiment of the present invention.
7A is a graph illustrating output characteristics of an organic light emitting transistor according to an exemplary embodiment of the present invention, and FIG. 7B is a graph illustrating transfer characteristics of an organic light emitting transistor according to an exemplary embodiment of the present invention.

The objects, specific advantages and novel features of the present invention will become more apparent from the following detailed description and the preferred embodiments associated with the accompanying drawings. In the present specification, in adding reference numerals to the components of each drawing, it should be noted that the same components as possible, even if displayed on different drawings have the same number as possible. In addition, terms such as “first” and “second” are used to distinguish one component from another component, and the component is not limited by the terms. In the following description, detailed descriptions of related well-known techniques that may unnecessarily obscure the subject matter of the present invention will be omitted.

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

1 is a cross-sectional view of an organic light emitting transistor according to an embodiment of the present invention, FIG. 2 is a plan view of an organic light emitting transistor according to an embodiment of the present invention, and FIG. 3 is an operating principle of the organic light emitting transistor according to an embodiment of the present invention. It is a perspective view explaining.

1 to 2, an organic light emitting transistor according to an embodiment of the present invention includes a substrate 10 and hafnium oxide (HfO _X ), and an insulating layer 30 formed on an upper surface of the substrate 10. , n-dodecylphosphonic acid (n-dodecylphosphonic acid, PA-C12), the self-assembly layer 40 formed on the insulating layer 30 (on), a pentacene compound (pentancene) compound, The hole transport layer 50 formed on the self-assembled layer 40, and 4- (dicyanomethylene) -2-methylene-6- (pi-dimethylaminostriyl 1) -4H-pyran (4- (dicyanomethylene) -2-methyl-6- (p-dimethylaminostyryl) -4H-pyran, DCM) doped with tris (8-hydroquinoline) aluminum (Alq ₃ ), The light emitting layer 60 is formed on the hole transport layer 50.

The organic light emitting transistor according to the present invention is an organic electronic device capable of controlling the emission phenomenon and may play an important role in the next generation active organic light emitting display industry, the substrate 10, the insulating layer 30, the self-assembled layer 40 ), A hole transport layer 50, and a light emitting layer 60.

Here, the substrate 10 may be an n-type silicon substrate 10. At this time, the substrate 10 is used as an input electrode to apply a gate voltage (see FIG. 3). However, the substrate 10 is not necessarily limited to the n-type silicon substrate 10 and may be a plastic substrate 10. The plastic substrate 10 may be made of polyethersulphone (PES), polyacrylate, polyetherimide (PEI), polyethylene naphthalate (PEN), polyethylene terephthalate (polyethyeleneterepthalate, PET) , Polyphenylene sulfide (PPS), polyarylate (PAR), polyimide (PI), polycarbonate (PC), cellulose triacetate (TAC) and cellulose acetate propionate ( cellulose acetate propinonate (CAP). Meanwhile, when the substrate 10 is the plastic substrate 10, the organic light emitting transistor according to the present invention may further include a gate electrode 20 disposed on the bottom surface of the substrate 10 to apply a gate voltage. .

The insulating layer 30 is a layer formed on the upper surface of the substrate 10, and is formed by depositing hafnium oxide (HfO _X ). Here, since hafnium oxide is a material having a high dielectric constant, the insulating ability of the insulating layer 30 is improved, so that the organic light emitting transistor according to the present invention can be driven even at a low voltage. At this time, the thickness of the insulating layer 30 is 650 kPa, but is not necessarily limited thereto. The self-assembled layer 40 is disposed on the insulating layer 30.

The self-assembled layer 40 is made of an n-dodecylphosphonic acid (PA-C12) self-assembled body, and is formed on the insulating layer 30 by a immersion method. The self-assembled layer 40 prevents mismatch between the insulating layer 30 and the organic semiconductor, thereby improving the electric field mobility of the organic semiconductor and ensuring device stability in the air.

Meanwhile, the hole transport layer 50 is a layer formed on the self-assembled layer 40, and is formed by depositing a pentacene compound. In this case, the thickness of the hole transport layer 50 may be 90 ~ 110 110. However, the thickness is not necessarily limited thereto.

The light emitting layer 60 is formed on the hole transport layer 50, where the light emitting layer 60 is 4- (dicyanomethylene) -2-methylene-6- (pi-dimethylaminostriyl 1) -4H— A mixture of pyran (4- (dicyanomethylene) -2-methyl-6- (p-dimethylaminostyryl) -4H-pyran, DCM), and (8-hydroquinoline) aluminum (tris (8-hydroxyquinoline) aluminum, Alq ₃ ) Is formed. That is, the light emitting layer 60 is formed by Alq ₃ doped with DCM, wherein the doping concentration of DCM may be 0.5 to 1.0 mol%. On the other hand, the thickness of the hole transport layer 50 may be 90 ~ 110 kPa, but is not necessarily limited thereto, and may have a thickness in a different range depending on the doping concentration and the process conditions.

Overall, the organic light emitting transistor according to the present invention has a structure in which the substrate 10, the insulating layer 30, the self-assembled layer 40, the hole transport layer 50, and the light emitting layer 60 are sequentially stacked. Furthermore, the electron transport layer 70, the source electrode 80 and the drain electrode 90 may be further included.

The electron transport layer 70 is formed of N, N'-ditridecyl perylene-3,4,9,10-tetracarboxylic diimide (N, N'-ditridecylperylene-3,4,9,10-tetracarboxylic diimide, P13) is formed by depositing a compound on the light emitting layer (60). At this time, the thickness of the electron transport layer 70 may be 290 ~ 310Å. However, it is not necessarily limited to the thickness range. As a main component of the electron transport layer 70 deposited on the organic device in the present invention, a P13 compound is used. In this case, a compound used in the formation of a conventional hole transport layer 50 such as tetracene, a thiophene oligomer, which is a p-type material, is used. Compared with those of the n-type transistor, the field mobility is excellent, and the field mobility is significantly improved compared to that of Alq ₃ , TCNQ, and the like, which are generally used for n-type materials.

The source electrode 80 and the drain electrode 90 are disposed on the electron transport layer 70 and face each other at predetermined intervals. Therefore, a channel C is formed between the source electrode 80 and the drain electrode 90, where the channel length L is 200 μm and the channel width W may be 10 mm. Here, the channel length may correspond to the interval between the source electrode 80 and the drain electrode 90, and the channel width may correspond to the length of the source electrode 80 and the drain electrode 90, respectively. The source electrode 80 and the drain electrode 90 may be Au, Ag, Pt, or the like as a metal electrode, but the material is not necessarily limited thereto.

The emission principle of the organic light emitting transistor according to the present invention is as follows.

Referring to FIG. 3, when 0 to ± 10 V is applied to the gate electrode and ± 10 V is applied to the drain electrode, electric charges are generated in the gate, and thus holes are stacked in the hole transport layer. Electrons in the electron transport layer are induced by the stacked holes, and holes and electrons recombine in the Alq ₃ : DCM emitting layer to generate light.

Hereinafter, a method of manufacturing an organic light emitting transistor according to the present invention will be described. At this time, the above-described parts of the organic pore transistor according to the present invention will be omitted or simply described.

4 is a cross-sectional view of a vaporization apparatus for manufacturing an organic light emitting transistor according to an embodiment of the present invention.

In the method of manufacturing an organic light emitting transistor according to an embodiment of the present invention, A) forming a gate electrode on the lower surface of the substrate, B) depositing hafnium oxide (HfO _X ) on the upper surface of the substrate to form an insulating layer C) immersing the substrate in a solution of n-dodecylphosphonic acid (PA-C12) dissolved in ethanol to form a self-assembled layer on the insulating layer, D) inside the cluster beam deposition chamber. Inserting a substrate into the substrate, E) depositing a hole transport layer on the self-assembled layer by vaporizing the pentacene compound by heating it in a first crucible and supplying it inside the cluster beam deposition chamber, F) A tris (8-hydroxyquinoline) aluminum (Alq ₃ ) compound is placed in a second crucible, and 4- (dicyanomethylene) -2-methylene-6 is placed in a third crucible. -(Pi-dimethylaminostriyl 1) -4 Chi-pyran (4- (dicyanomethylene) -2-methyl-6- (p-dimethylaminostyryl) -4H-pyran, DCM) compound was added, and then each was vaporized by heating to feed each into the cluster beam deposition chamber. Thereby depositing a light emitting layer on the electron transport layer, G) N, N'-ditridecyl perylene-3,4,9,10-tetracarboxylic diimide (N, N'-ditridecylperylene) inside the fourth crucible -3,4,9,10-tetracarboxylic diimide (P13) compound is vaporized by heating, and deposited inside the cluster beam deposition chamber to deposit an electron transport layer on the light emitting layer, and H) drain on the electron transport layer Forming an electrode and a source electrode.

The organic light emitting transistor according to the present invention is manufactured by the following method.

First, the vacuum deposition equipment used according to the present invention will be described with reference to FIG. 4, and the substrate holder 130 is fixed to a substrate (not shown) on the inner upper side of the vacuum chamber, and a support 101 on the inner lower side. At least one crucible (102, 103) having a heating wire as a heating means is disposed on the top of the crucible (102, 103) is formed on the top of the crucible (102, 103) with a nozzle is formed so that the crucible (102, 103) of the top Except for the nozzle, it will have a closed shape, and the materials to be deposited are placed therein. In addition, the thickness monitor 100 installed in order to measure the thickness of the deposited thin film is represented by the deposition rate and thickness of the deposited thin film in 박막 / s and k 각각 respectively, so that the thickness of the thin film can be monitored and the appropriate thickness can be adjusted. do. In addition, the shutter 110 is positioned in the middle of the substrate and the crucibles 102 and 103 so as to be opened and closed from the outside and is initially closed, thereby preventing the deposition of unpurified impurities and maintaining a constant deposition rate. When it reaches, it is provided to be rotated and opened from the outside.

Using the vacuum deposition equipment, the method of manufacturing the organic light emitting transistor of the present invention described above in more detail, step A) is to form a gate electrode (or an input electrode) on the lower surface of the substrate as commonly used in the art It is not specifically limited as long as it is a method. Here, since the substrate has been described above, a detailed description thereof will be omitted.

Next, as a step B), hafnium oxide (HfO _x ), which is a material having a large dielectric constant, is deposited on the upper surface of the substrate to form an insulating layer. More specifically, first, 1.28 g of hafnium chloride (HfCl ₄ ) was dissolved in 8 ml of ethanol to make a zirconium precursor solution, and then 0.6 g of nitric acid (HNO ₃ ) was added thereto for 3 hours at 50 ° C. Heat treatment. The finished hafnium precursor is spin coated at 5000 rpm for 30 seconds. After this step, the substrate is heated to a temperature of 500 ° C. in a hot plate for 2 hours, and then cooled at room temperature. As the condensation reaction proceeds due to the heat treatment, HfO _x is formed.

When the insulating layer is formed in this way, step C) is performed to form a self-assembled layer on the insulating layer. After dissolving the 0.0125g PA-C12 self-assembled body in 100mm of ethanol, the self-assembled layer may be formed by immersing the substrate on which the HfO _x insulation layer is formed for 12 hours. At this time, the thickness of the HfO _x insulating layer using the PA-C12 magnetic assembly formed is 650 kPa.

Then, as step D), the substrate is inserted into the cluster beam deposition chamber. As described above, at least one crucible is disposed inside the cluster beam deposition chamber, each crucible having a nozzle. Here, the material of the crucible is not particularly limited as long as the compounds are not adsorbed or reacted when heating a compound such as pentacene, Alq ₃ , DCM, P13, which will be described later, but may be heated at a high temperature and heated at a high temperature. Graphite with less deformation is preferred. In addition, the shape of the crucible is not particularly limited as long as it can be closed and a cover having a nozzle thereon, preferably spin coating is easy to form a thin film is advantageous. Meanwhile. The nozzle is a passage through which the compounds are sublimed and discharged toward the substrate, and the diameter thereof may be 0.5 to 1.5 mm. If the diameter of the nozzle provided in the crucible is less than 0.5 mm, it is not preferable because the clustered vapor particles described later are difficult to pass through the nozzle. If the diameter of the nozzle is greater than 1.5 mm, the clustered molecules become too large to have an even thin film layer when moving. It is not preferable because it is difficult to form. Therefore, the kinetic energy generated while passing through the nozzle having a diameter of 0.5 to 1.5 mm can supply energy required for migration to form an even thin film. Therefore, there is an advantage that can be deposited at room temperature without heating in the deposition step by the mobile energy.

Once the substrate is inserted into the chamber, the hole transport layer is deposited according to step E). To this end, a pentacene compound is put into a first crucible having a first nozzle, and the compound is vaporized by heating by a voltage application method. The vaporized compound is then supplied into the cluster beam deposition chamber through a first nozzle, thereby forming a hole transport layer on the substrate. At this time, a voltage of 6.0 to 8.0V may be applied to the crucible. If a voltage of less than 7.0 V is applied, organic matter may not be sublimated, and thus, deposition may not occur smoothly. If the voltage exceeds 9.0 V, the deposition rate may not be controlled. In addition, the temperature of the first crucible may be preferably 220 ~ 250 ℃. If the internal temperature of the first crucible is less than 220 ° C., the compound is difficult to vaporize, and the organic thin film is difficult to form because it cannot supply sufficient energy necessary for thermal polymerization to occur on a flat substrate, and exceeds 250 ° C. In this case, since the chemical composition of the material forming the thin film may be in a denatured form, the roughness of the surface may also be deteriorated.

A more detailed description of the deposition process, the cluster sublimated through the nozzle of the crucible will proceed to the inner upper side of the vacuum chamber and collide with the bottom of the substrate. The impacted cluster breaks weak intermolecular bonds and becomes the original sublimed organic particles and moves to the surrounding voids to bond with the substrate. On the other hand, the surfactant may be laminated on the surface of the substrate before depositing the cluster. In the case of using the pentacene compound, the thickness may be 90 to 110 Pa, and the deposition rate of the cluster is preferably 0.5 to 1.0 Pa / S. When the deposition rate is less than 0.5 Pa / S, the deposition rate of the thin film is When too slow, the organic thin film is difficult to form properly, and when the thickness exceeds 1.0 dl / S, the roughness of the manufactured organic thin film may be poor.

On the other hand, it is preferable not to heat the substrate at the time of cluster beam deposition, more preferably the vaporized cluster may be deposited at room temperature of 20 to 30 ℃ to form an organic film. If the substrate is heated, not only the production cost required for heating is increased but also it is difficult to establish the temperature uniformity of the entire substrate as a process condition as it is enlarged.

When the pentacene compound is heated in a vacuum state, the pentacene compound is sublimed into a gas by a phase change, and the sublimed compound particles flow inside the first crucible. The flowing particles pass through a nozzle formed at the top of the crucible, which passes through a small hole in the nozzle, so that only particles having a kinetic energy in one direction, that is, move upwards, that is, through the nozzle. You can do it. Therefore, the vaporized particles inside the crucible flow inside the crucible and collide with each other to form clusters with weak intermolecular attraction, and only those clusters with upward direction have uniform and constant kinetic energy, It passes through the nozzle in the form of a beam and proceeds toward the inner upper side of the vacuum chamber. In this way, the clusters having the direction toward the top and at the same time having uniform and constant kinetic energy collide with the lower part of the substrate arranged on the inner side of the vacuum chamber, and the weak intermolecular attraction of the cluster is broken by the collision and the remaining motion at the same time. The vacancy around the impingement by energy is searched for and deposited and the thickness of the thin film formed eventually becomes uniform, resulting in excellent crystallinity.

On the other hand, according to the conventional physical vapor deposition (PVD) method or OMBD method, the organic molecules to be deposited do not move in the vacuum chamber with a specific orientation, but rather as the dish-shaped vessel is heated. Evaporation occurs directly into the vacuum environment. This is different from the cluster in the cluster beam deposition according to the present invention, the organic molecules are aggregated with a weak attraction force to form a cluster. In other words, organic molecules having various directions of directional energy and kinetic energy having a wide distribution size are sublimated to the surroundings in a vacuum state. Thus, particles with a wide range of kinetic energies are deposited more or less from various directions so that the surface of the substrate has a rough island shape. Therefore, the surface of the organic molecules to be deposited is roughened, the crystallinity is lowered to reduce the field mobility.

Next, as step F), the Alq ₃ compound is placed in the second crucible, the DCM compound is placed in the third crucible, and the second and third crucibles are placed inside the cluster beam deposition chamber. At this time, each compound is heated and vaporized by a voltage application method, so that each vaporized compound is supplied into the cluster beam deposition chamber through the second and third nozzles to form a light emitting layer on the substrate. Here, using the photoluminescence spectra equipment to derive the doping concentration of the mixture for producing the optimum light emitting layer, the optimum doping concentration is preferably 0.5 ~ 1.0 mol%. The range of PL corresponding to 0.5 to 1.0 mol% is 575 to 590 nm, and for this purpose, a voltage of 10.0 to 12.0 V may be preferably applied to the second crucible. If a voltage of less than 10.0 V is applied, organic matter does not sublimate, which may cause a problem of poor deposition. If it exceeds 12.0 V, the deposition rate cannot be controlled and the doping concentration of DCM exceeds 1.0 mol%. This may cause problems.

On the other hand, the temperature of the second crucible may be preferably 330 ~ 350 ℃. If the temperature inside the second crucible is less than 330 ° C., the compound is difficult to vaporize, and the organic thin film is difficult to be formed because it cannot supply sufficient energy for thermal polymerization to occur on a flat substrate. Insufficient temperature prevents DCM from doping smoothly. If the temperature exceeds 350 ° C., the chemical composition of the material forming the thin film may be in a denatured form, the surface roughness may be poor, and the concentration of DCM exceeds 1.0% mol due to the high internal temperature of the third crucible. Not desirable

In addition, a surfactant may be deposited on the surface of the substrate prior to depositing the cluster. In addition, when using the compound, the thickness may be 390 ~ 410 mm. In addition, the deposition rate of the cluster is preferably 0.1 to 0.3 Å / S, when the deposition rate is less than 0.1 Å / S, because the deposition rate of the thin film is too slow to form an organic thin film is well formed and exceeds 0.3 Å / S In this case, the roughness of the manufactured organic thin film may be poor.

When the light emitting layer is formed in this way, the electron transport layer is deposited as a step G). The P13 compound may be vaporized by being placed inside the fourth crucible and heated by a voltage application method, and the electron transport layer may be deposited on the substrate by supplying the vaporized compound into the cluster beam deposition chamber through the fourth nozzle. At this time, preferably a voltage of 7.0 ~ 9.5V can be applied. If a voltage of less than 7.0 V is applied, organic matter may not be sublimed, and thus, deposition may not occur smoothly. If the voltage is higher than 9.5 V, the deposition rate may not be controlled. On the other hand, the temperature of the fourth crucible may be preferably 270 ~ 300 ℃. If the internal temperature of the fourth crucible is less than 270 ° C., the compound is difficult to vaporize, and the organic thin film is difficult to be formed because it cannot supply sufficient energy necessary for thermal polymerization to occur on a flat substrate, and exceeds 300 ° C. In this case, since the chemical composition of the material forming the thin film may be in a denatured form and the roughness of the surface becomes worse, it is not preferable.

In the case of using the compound, the thickness may be 290 to 310 Pa, and the deposition rate of the cluster is preferably 1.0 to 2.0 Pa / S. When the deposition rate is less than 1.0 Pa / S, the deposition rate of the thin film is If it is too slow, the organic thin film is difficult to form properly, and when it exceeds 2.0 GPa / S, the roughness of the manufactured organic thin film may be poor.

Finally, in step H), a drain electrode and a source electrode are formed on the electron transport layer. At this time, two electrodes may be formed through a conventional method.

5 is an image photographing the emission of the organic light emitting transistor according to an embodiment of the present invention with a CCD camera. As shown in FIG. 5, the organic light emitting transistor manufactured by the aforementioned method exhibits light emission characteristics as intended as a predetermined voltage is applied.

Hereinafter, the present invention will be described in more detail with reference to preferred embodiments of the present invention, but the present invention is not limited thereto.

<Example 1>

Formation of 1- (1) heat transfer layer

Hafnium oxide (HfO _x ) was deposited to a thickness of 650 Pa by using a solution process on top of the silicon substrate.

Formation of 1- (2) Self-Assembly Layer

A PA-C12 self-assembly was deposited on top of the insulating layer substrate by immersion.

1- (3) hole transport layer deposition

A 10-inch diffusion pump with a baffle is used to maintain the vacuum in the vacuum chamber at an average of 1 × 10 ^-5 Torr, and graphite with a cover with a nozzle 1 mm in diameter on top. The first crucible of the material was placed on the inner side of the vacuum chamber and placed on the inner side of the vacuum chamber with the surface on which the HfO _x / PA-C12 of the n-type silicon substrate was stacked face down. At this time, the distance between the n-type silicon substrate and the first crucible was 190mm. Next, pentacene was added to the inside of the first crucible, and a hole transport layer having a thickness of 90 to 110 kPa was deposited under a condition of a heating temperature of 220 to 250 ° C. and a deposition rate of 0.5 to 1.0 mW / sec. Here, the temperature of the substrate was maintained at 20 ° C.

1- (4) Emissive Layer Deposition

Alq ₃ and DCM were introduced into the second crucible and the third crucible, respectively, and a voltage was applied to deposit a light emitting layer having a thickness of 390 to 410 Å with a heating temperature of 330 to 350 ° C. and a deposition rate of 0.1 to 0.3 Å / sec. It was.

 1- (5) electron transport layer deposition

The P13 compound was introduced into the fourth crucible and a voltage was applied thereto to deposit an electron transport layer having a thickness of 390 to 410 Å with a heating temperature of 270 to 300 ° C. and a deposition rate of 1.0 to 2.0 Å / sec.

1- (6) source and drain electrode formation

Next, an organic light emitting transistor was fabricated by simultaneously forming a source electrode and a drain electrode using a vacuum mask using gold (Au) as an electrode material, a thin film thickness of 500Å, a channel width of 10 mm, and a channel length of 200 μm. It was.

<Example 2>

In the case of the organic field effect transistor in a single layer in Example 1, only the pentacene compound of 1- (3) was deposited to a thickness of 500 Å to manufacture a device.

<Example 3>

In Example 1, in the case of the organic field effect transistor as a single layer, only the P13 compound of 1- (5) was deposited to a thickness of 500 Å to manufacture a device.

Experimental Example

Physical properties of the n-type field effect transistors manufactured by the method of Examples 1 to 3 were evaluated by the following method and the results are shown in Table 1 below.

Classification
(thickness) μ _eff ^{h, avg} ± σ
(Cm2 / Vs) μ _eff ^{e, avg} ± σ
(Cm2 / Vs) Light emitting area V _GS (-) V _GS (+) pentacene (500 kPa) 0.34 ± 0.05 - - - P13 (Å) - 0.16 ± 0.04 - - pentacene / Alq ₃ : DCM / P13
(100/400/300 Å) 0.28 ± 0.11 0.04 ± 0.02 Drain Source

 The bipolar organic light emitting transistor prepared in Example 1 was shown in FIGS. 6 and 7 by measuring electrical characteristics in air.

FIG. 6A is a graph illustrating capacitance of an organic light emitting transistor according to an embodiment of the present invention, and FIG. 6B is a graph illustrating leakage current of an organic light emitting transistor according to an embodiment of the present invention, and a drain sweep of a typical bipolar organic light emitting transistor. sweep), which shows how holes and electrons move with the gate voltage. For example, when a negative voltage is applied to V _DS , electrons are preferentially injected when the gate voltage is 0 V. As the negative voltage of the gate increases, the role of holes appears.

FIG. 7A is a graph illustrating output characteristics of an organic light emitting transistor according to an embodiment of the present invention, and FIG. 7B is a graph illustrating transfer characteristics of an organic light emitting transistor according to an embodiment of the present invention. Sweep) curve, that is, the values of the field mobility (μ _FET , cm ² / Vs), the current flicker ratio (I _{ON / OFF} ), the threshold voltage (V _T , V) can be derived by Equation 1 below. Can be.

<Equation 1>

However, in Equation 1, L is the width of the channel between the drain and the source (μm), I _DS is the current flowing between the source and the drain electrode, W is the length of the channel between the source and drain electrode and C _i is the electrical Capacity and unit is nF / cm ² to be. V _GS is the voltage (volts) between the source and gate electrodes and V _T is the threshold voltage.

Overall, the organic light emitting transistor according to the present invention can be driven at a low voltage by using an insulating layer having a high dielectric constant, and a light emitting layer is disposed between the hole transport layer and the electron transport layer to increase the luminous efficiency. In addition, by depositing an electron transport layer and a hole transport layer with a predetermined compound, the electric field mobility in the air and the stability of the device is improved, the present invention can provide a motif that can be easily developed a drive circuit in the future.

Although the present invention has been described in detail through specific examples, it is intended to describe the present invention in detail, and the present invention is not limited thereto, and should be understood by those skilled in the art within the technical spirit of the present invention. It is obvious that modifications and improvements are possible.

All simple modifications and variations of the present invention fall within the scope of the present invention, and the specific scope of protection of the present invention will be apparent from the appended claims.

10: substrate 20: gate electrode
30: insulating layer 40: self-assembled layer
50: hole transport layer 60: light emitting layer
70: electron transport layer 80: source electrode
90: drain electrode

Claims (12)

delete delete delete delete delete delete delete A) forming a gate electrode on the lower surface of the substrate;
B) depositing hafnium oxide (HfO _X ) on the upper surface of the substrate to form an insulating layer;
C) immersing the substrate in a solution of n-dodecylphosphonic acid (PA-C12) dissolved in ethanol to form a self-assembled layer on the insulating layer;
D) inserting said substrate into a cluster beam deposition chamber;
E) depositing a hole transport layer on the self-assembly layer by vaporizing by putting a pentacene compound inside a first crucible and heating it, and supplying it inside the cluster beam deposition chamber;
F) A tris (8-hydroxyquinoline) aluminum (Alq ₃ ) compound was placed in a second crucible, and 4- (dicyanomethylene) -2-methylene was placed in a third crucible. -6- (Py-dimethylaminostriyl 1) -4 H-pyran (4- (dicyanomethylene) -2-methyl-6- (p-dimethylaminostyryl) -4H-pyran, DCM) compound, and then each Vaporizing by heating to deposit a light emitting layer on the hole transport layer by supplying each into the cluster beam deposition chamber;
G) N, N'-ditridecylperylene-3,4,9,10-tetracarboxylic diimide (N, N'-ditridecylperylene-3,4,9,10-tetracarboxylic diimide in the fourth crucible Depositing an electron transport layer on the light emitting layer by vaporizing the compound by heating and supplying the compound to the inside of the cluster beam deposition chamber; And
H) forming a drain electrode and a source electrode on the electron transport layer;
Step B) is
Dissolving hafnium chloride (HfCl ₄ ) in ethanol, followed by addition of nitric acid (HNO ₃ ) and heat treatment to produce a hafnium precursor;
Spin coating the hafnium precursor on an upper surface of the substrate; And
Heating the spin-coated substrate to a temperature of 500 ° C. in a hot plate;
Cooling the heated substrate at room temperature; manufacturing method of an organic light emitting transistor comprising a.
The method according to claim 8,
The temperature of the first crucible is 220 ~ 250 ℃, the temperature of the second crucible is 330 ~ 350 ℃, the temperature of the fourth crucible is 270 ~ 300 ℃ manufacturing method of an organic light emitting transistor.
The method according to claim 8,
The deposition rate of the hole transport layer is 0.5 ~ 1.0 Å / s, the deposition rate of the light emitting layer is 0.1 ~ 0.3 Å / s, the deposition rate of the electron transport layer is 1.0 ~ 2.0 Å / s method of manufacturing an organic light emitting transistor.
The method according to claim 8,
The first crucible, the second crucible, the third crucible, and the fourth crucible each include a nozzle for supplying a vaporized compound into the cluster beam deposition chamber, and the diameter of the nozzle is 0.5 to 1.5 mm. Method for manufacturing a transistor.
The method according to claim 8,
Each of the first crucible, the second crucible, the third crucible, and the fourth crucible is heated by a voltage application method,
Fabrication of an organic light emitting transistor applying a voltage of 6 to 8 V to the first crucible, a voltage of 10 to 12 V to the second and third crucibles, and a voltage of 7 to 9.5 V to the fourth crucible Way.

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