KR102091427B1 - Combination sturcture between an asymmetric organic semiconductor layer and electrode for injection and extraction of charge of organic semiconductor and manufacturing method of the same - Google Patents

Abstract

The present invention relates to a coupling structure of an asymmetric organic semiconductor layer and an electrode for charge injection and extraction of an organic semiconductor and a manufacturing method thereof. An objective of the present invention is to maximize the efficiency of an electrode to improve element performance. According to an embodiment of the present invention, the coupling structure of an asymmetric organic semiconductor layer and an electrode for charge injection and extraction of an organic semiconductor comprises: a glass substrate; a source electrode and a drain electrode formed on the glass substrate; self-assembled monolayers (SAMs) in a form of 2,3,4,5-pentafluorobenzene thiol (PFBT) formed on the source electrode; self-assembled monolayers (SAMs) in a form of thiophenol (TP) formed on the drain electrode; and an active layer of dinaphtho[2,3-b:2′,3′′-f]thieno[3,2-b]thiophene (DNTT) to prevent infiltration of moisture and oxygen into the source electrode and the drain electrode.

Description

Combined structure of asymmetric organic semiconductor layer and electrode to improve charge injection and extraction of organic semiconductor and method of manufacturing the organic electronic device thereof THE SAME}

The present invention relates to a combined structure of an asymmetric organic semiconductor layer and an electrode for injection and extraction of charge from an organic semiconductor and a method of manufacturing the same.

Recently, many studies have been actively conducted for the development of high performance organic thin film transistors using organic semiconductors for solution processing worldwide. In particular, in the organic thin film transistor, the crystallinity of the organic semiconductor thin film and the interface between the organic semiconductor layer and the metal electrode are important factors for determining device performance, and the crystallinity of the organic semiconductor thin film is an important factor for charge mobility in the device. In general, it is possible to improve the crystallinity of the organic semiconductor thin film through a heat treatment post-treatment process. However, since an interface dewetting phenomenon occurs on the electrode surface, a problem arises in interface stability, while improving the microstructure of the organic semiconductor thin film and interfacing with an insulator. It is essential to develop a new process technology to prevent dewetting in Esau.

The interface between the organic semiconductor layer and the metal electrode is a key factor in determining contact resistance, and research is being conducted to reduce contact resistance by applying various organic material insertion layers.

What affects the contact resistance at the interface between the organic semiconductor layer and the metal electrode is charge injection from the source electrode to the organic semiconductor layer and charge extraction from the organic semiconductor layer to the drain electrode. Since this depends on the position of the Fermi level of the metal, in order to lower the charge injection barrier, a metal having an appropriate work function must first be selected. In general, in the case of a P-type semiconductor, the larger the work function, the smaller the charge injection barrier, which is advantageous for hole injection. Therefore, since the work function of the gold electrode is 5.1 eV, it can be expected that hole injection of the p-type transistor is easy. In fact, the results of measuring the contact resistance of various metals (Au (5.4 eV), Ag (4.8 eV), Cu (4.7 eV), Cr (4.3 eV), Al (4.1 eV) with different work functions for organic semiconductors) , It has been reported that the contact resistance decreases as the work function of the electrode increases.

In addition, a study looking at the performance of pentacene transistors reported a high hole injection barrier for metals with low work function (Al (4.2eV)), resulting in low field effect mobility. However, it has been reported that the gold electrode (Au) with a high work function also creates an interfacial dipole barrier at the interface with the organic semiconductor, thereby increasing the hole injection barrier. As described above, the charge injection barrier can vary greatly depending on the work function and surface properties of metals, and because it has a great influence on electrical properties, many research groups worldwide are self-assembled, self-assembled monolayers, which are organic monolayers spontaneously formed on the substrate surface. Research has been conducted to change the work function of metal electrodes using monolayers (SAMs).

In the present invention, the work function of the gold electrode can be suitably adjusted to the roles of the source and drain electrodes by using a thiol-based monomolecular film having different end groups. Through the surface modification of the gold electrode, the work function of the source electrode is increased and the work function of the drain electrode is lowered to lower the hole injection barrier from the source electrode to the organic semiconductor and to lower the barrier for hole extraction from the organic semiconductor to the drain electrode to operate the transistor element. The performance could be greatly improved.

J. Appl. Phys, 94, 6129 (2003), L.Burgi, T, J.Richards, R.H.Friend Proceedings of the IEEE., 93, 1265 (2005), T, Zyung, S.H.Kim, H.Y.Chu,

The present invention was developed to solve the above problems, and a source and a drain were manufactured using gold, which is a typical metal electrode, and hole injection from the source to the organic semiconductor layer and hole extraction performance from the organic semiconductor layer to the drain were improved. Different SAM materials are modified on the source and drain surfaces so that dinaphtho [2,3-b: 2 ′, 3 ′ '-f] thieno [3,2-b] thiophene ( DNTT) is used as a representative organic active layer to maximize the efficiency of the electrode to improve the device performance.

In addition, in order to exhibit the optimum efficiency of the source and drain whose surface is modified, it can be said that a manufacturing method capable of improving physical properties as a semiconductor device is required, and the characteristics of the semiconductor can be optimized while utilizing the characteristics of the organic semiconductor. Another object of the present invention is to provide a method for manufacturing an organic semiconductor including a surface-modified source and drain.

On the other hand, other objects not specified in the present invention will be additionally considered within a scope that can be easily inferred from the following detailed description and its effects.

In order to achieve the above object, the assembling structure of the asymmetric organic semiconductor layer and the electrode for charge injection and extraction of the organic semiconductor according to an embodiment of the present invention, a glass substrate; and, a source (source formed on the glass substrate) ) Electrode and drain electrode; and self-assembled monolayers (SAMs) in the form of 2,3,4,5-pentafluorobenzene thiol (PFBT) formed on the source electrode; and on the drain electrode Self-assembled monolayers (SAMs) in the form of thiophenol (TP); And a ferrule insulator for preventing the penetration of oxygen and moisture into the source and drain electrodes; and, DNTT (dinaphtho [2,3-b: 2 ′, 3 ′ '-f] thieno [ 3,2-b] thiophene) and a single-molecule active layer.

In one embodiment of the present invention, the coupling structure between the asymmetric organic semiconductor layer and the electrode may further include a gate electrode.

In one embodiment of the present invention, the source electrode and the drain electrode may be formed of a gold (Au) material.

In one embodiment of the present invention, the self-assembled monolayer is chemically adsorbed to the source and drain electrodes to induce the movement of the Fermi level, and to induce a dipole toward the metal surface. It may be able to contribute to the increase or decrease of the metal work function.

In one embodiment of the present invention, the modification of the self-assembled monolayer may be capable of controlling charge injection and extraction between the active layer and the electrode interface.

A method of manufacturing an organic semiconductor transistor including an asymmetric organic semiconductor layer and an electrode for injection and extraction of charge of an organic semiconductor according to an embodiment of the present invention, a source electrode by a method of thermal deposition on a glass substrate And depositing a drain electrode (s10); and chemically adsorbing 2,3,4,5-pentafluorobenzene thiol (PFBT) type self-assembled monolayers (SAMs) on the source electrode ( s20); and chemically adsorbing thiophenol (TP) type self-assembled monolayers (SAMs) on the drain electrode (s30); and, organic molecular beam deposition system (OMBD) ) To form an active layer of DNTT (dinaphtho [2,3-b: 2 ′, 3 ′ '-f] thieno [3,2-b] thiophene) (s40); and, the DNTT Forming a polymer gate dielectric layer on the active layer (s50): and the polymer gate dielectric And forming a gate electrode on the layer (s60).

In one embodiment of the present invention, the TP-type self-assembled monomolecular film may increase the surface energy of the drain electrode.

In one embodiment of the present invention, the PFBT type self-assembled monomolecular film may take the form of a halogenated phenyl group and reduce the surface energy of the source electrode.

In one embodiment of the present invention, the asymmetrically functionalized S / D electrode may be able to improve electrical mobility of the organic field effect transistor by improving charge mobility and lowering contact resistance and channel resistance.

The bonding structure of the asymmetric organic semiconductor layer and the electrode for the injection and extraction of charge of the organic semiconductor according to the technical idea of the present invention improves the electrical properties of the organic field effect transistor and additional hole density, surface potential (surface) The electrical performance of various organic electronic devices, such as inverters, solar cells and sensors, can be improved by changing the potential and work function.

In addition, due to the rapid development of device processing of organic electronic devices, organic field effect transistors are being studied and used in various potential applications, such as flat panel displays, memory devices, complementary circuits, and academic sensors. And organic electronic products such as biological sensors. In addition, it has contributed to improving the charge capacity of an organic semiconductor (OSC) by improving the film microstructure near the gate dielectric through surface or interface engineering of the organic electronic product.

The assembling structure of the asymmetric organic semiconductor layer and the electrode for improving the charge injection and extraction performance of the organic semiconductor according to an embodiment of the present invention also inserts a metal oxide, an ionic intermediate layer, an organic buffer layer or graphene at the electrode / OSC interface It has disadvantages with respect to material dependence, application under limited conditions, device configuration, chemical reactivity, etc., and in an embodiment of the present invention as an improvement therefor, surface functionalization of a self-assembled monolayer The crystallization process could be influenced by modifying the interfacial energy and chemical reaction through, and such a SAM is chemically adsorbed on the electrode surface of the source and drain to induce movement of the Fermi level, and the highest occupied molecular orbital function of the semiconductor (Highest The work function of the electrode can be adjusted to match the Occupied Molecular Orbital (HOMO). By modifying the surface dipole (dipole), by manufacturing a device having a contact (ohmic contact) it is possible to adjust the work function of the electrodes to optimize the electrical properties of the transistor.

The above-described effects of the present invention have been described by way of example, and the scope of the present invention is not limited by these effects.

1 is a view showing the chemical structure of a thiolate SAM and an organic field effect transistor (Organic Field Effect Transistor) according to an embodiment of the present invention.
2 is a view for explaining the structure of an organic semiconductor transistor including a DNTT layer and a parylene C gate dielectric layer according to an embodiment of the present invention.
3 (a), (b), (c), (d), and (e) are graphs showing output characteristics of DNTT OFETs according to various S / D electrodes, and FIGS. 4 (a), (b), ( c) and (d) are graphs showing transfer characteristics according to the gate voltage.
5A and 5B are graphs showing kinetic energy corresponding to secondary electrons, and graphs showing the relationship between work function (WF) and HOMO and LUMO, respectively.

Hereinafter, the present invention will be described in detail. The following examples and drawings are provided as examples in order to sufficiently convey the spirit of the present invention to those skilled in the art. In addition, unless otherwise defined in the technical terms and scientific terms used in the present invention, those skilled in the art to which this invention belongs have the meanings commonly understood, and the present invention in the following description and accompanying drawings Descriptions of well-known functions and configurations that may unnecessarily obscure the subject matter are omitted.

Hereinafter, a coupling structure of an asymmetric organic semiconductor layer and an electrode for injection and extraction of charge of an organic semiconductor according to an embodiment of the present invention will be described.

In the bonding structure of the asymmetric organic semiconductor for injection and extraction of charge of the organic semiconductor according to an embodiment of the present invention, the glass substrate 105 may be first included as a substrate.

In the organic semiconductor, the source electrode 110 and the drain electrode 120 may be typically included on the substrate 105. The source electrode 110 may be in a ground state, and a negative voltage may be applied to the drain electrode 120.

As described above, in the case of the organic semiconductor, it can be said that the problem of the contact state between the metal electrode and the organic material is a problem. In order to improve the problem, in one embodiment of the present invention, self-assembly is performed to improve the contact. It may include a self-assembled monolayer.

Self-assembled monolayers (SAMs) are used for a variety of purposes as a tool to control the interfacial properties of electrodes (eg, source and drain) and organic semiconductors (OSC). As described above, the self-assembled monomolecular films 130 and 140 may contribute in two aspects in one embodiment of the present invention.

That is, first, a surface functionalization function is exemplified. By modifying the surface energy and the chemical reaction, it affects the crystallization process of the polymer material. That is, not only can the packing of molecules in the grain be influenced, but also the grain boundary landscape in the crystalline film.

As another effect, the SAM is chemically adsorbed on the S / D electrodes 110 and 120 to induce the movement of the Fermi potential and dipole toward the electrode 110.120 surface. By inducing (dipole), each dipole can have a work function of the highest occupied molecular orbital (HOMO) and the electrodes 110 and 120 coincide. In this case, ohmic contact may occur between the electrodes 110 and 120 and the organic active layer 150.

With this principle, the SAM can change the characteristics of charge injection and charge extraction on the surfaces of the electrodes 110 and 120.

These characteristics may vary depending on whether the SAM has a characteristic of an electron donating group or belongs to an electron withdrawing group.

More specifically, in the case of TP (thio phenol) according to an embodiment of the present invention, it can be said that it has a property of an electron donating group, and in the case of PFBT (2,3,4,5 Pentafluoro benzene) It can be said to have the characteristic of an electron withdrawing. As described above, according to the tendency of the self-assembled monolayer coupled to the electrode 110. 120, a difference may occur in performance for charge injection and extraction of the semiconductor electrode source 110 and drain 120. .

For example, the alkane group (alkan group) can lower the work function (work function), in the case of a SAM terminated with a halogen (halogen) group can be induced in the direction of increasing the work function (work function).

Looking at the research so far, efforts are made to inject these SAMs into the electrode interface, but most studies focused on the insertion of symmetric SAMs.

As described above, in the contact between the electrode 110 and the organic active layer 150, asymmetric functionalization with respect to the surface of the electrode 110 is performed for each electrode 110 and 120. The efficiency of inflow and outflow of holes or electrons can be enhanced.

According to the studies so far, the addition of SAM to the electrodes 110, 120 can increase the field effect mobility for organic semiconductors by more than 10 times, and increase the contact resistance by 4 times. It can be reduced over.

For example, by adding phenol-SAM and PFBT-SAM to an inkjet printer, the work function (WF) can be decreased from 4.90 eV (for gold electrode) to 4.6 eV or 5.24 eV. Reported. This means that the threshold voltage (Vth) can be moved through the SAM including the SH group.

Such a configuration can be applied to solar cells (hotovoltic devices), light emitting transistors (LETs), photodetectors and sensors.

In the present invention, the focus is on the charge transfer from the electrodes 110 and 120 to the organic active layer 150 or from the organic active layer 150 to the electrodes 110 and 120 from the viewpoint of injection and extraction of charge. . In addition, the solvent effect (SAM 130, 140) of the SAM (130, 140) formed on the electrode (110. 120) through the vapor deposition process causes an effect of anchoring (anchoring) on the electrodes (110, 120) ( It may be configured to exclude the solvent effect).

In the present invention, in order to secure such a function, a DNTT (dinaphtho [2,3-b: 2 ′, 3 ′ '-f] thieno [3,2-b] thiophene) active layer was formed, through which The SAMs 130. 140 formed on the electrodes 110 and 120 could be prevented from being damaged due to exposure to oxygen or moisture.

For such a configuration, the organic semiconductor transistor of the present invention was designed to take a bottom contact and a top gate structure.

(Example 1)

1 is a view showing the chemical structure of a thiolate SAM and an organic field effect transistor (Organic Field Effect Transistor) according to an embodiment of the present invention.

Referring to FIG. 1, a source 110 and a drain electrode 120 may be formed on a glass substrate 105. The glass substrate 105 may be subjected to a cleaning process using acetone, isopropyl alcohol, and deionized water. A 3 nm thick Cr layer (not shown) and a 70 nm thick Au (gold) layer may be formed on the cleaned glass substrate 105 by using a heat mask using a shadow mask. The gold layer may be used as the source electrode 110 and the drain electrode 120.

At this time, the defined channel length and width were set to 200 μm and 1000 μm, respectively. In addition, the SAM structures TP and PFBT according to an embodiment of the present invention were formed by a deposition method for 20 minutes in a fume hood.

 In addition, the heat treatment was performed in the vacuum chamber on the source 110 and drain 120 electrodes equipped with the SAM-type functional group.

/ s의 고정 속도로 형성하였다.50 nm thick DNTT (dinaphtho [2,3-b: 2 ′, 3 ′) by using organic molecular baem deposition on the thus formed substrate 105, source 110 and drain 120 electrodes '-f] thieno [3,2-b] thiophene) active layer 0.2 under the basic pressure of about 10 ^-7 Torr

/ s.

The process was performed while observing the deposition thickness, deposition rate and substrate temperature with a monitor.

Thereafter, a polymer gate dielectric layer for depositing the gate electrode was formed. The polymer gate dielectric layer was formed using a 600 nm thick Parylene insulator.

This process was performed using chemical vapor deposition (CVD).

/ s의 속도로 쉐도우 마스크를 통해 형성하였다.Finally, the gold electrode layer 180 is 3.0 on the parylene insulator layer.

/ s was formed through a shadow mask.

(Comparative Examples 1 to 4)

As a corresponding comparative example 1, a source 110 and a drain 120 electrode without SAM, and as a comparative example 2 and 3, a source 110 and a drain 120 electrode having a symmetrical structure and a drain 120 electrode, PFBT (2,3,4,5 Pentafluoro benzene) formed source 110 and drain 120 electrodes were used, and as Comparative Example 4, TP formed source 110 electrode and PFBT formed drain electrode 120 were used. Did.

(Results and Discussion)

Surface energy was measured for each of the electrodes 110 and 120 thus deposited, and the contact angle of two probe solutions, in particular water and diiodomethane, was measured using a contact angle analyzer (Phoenix 300A, SEO Co.). .

Equation 1 used at this time is the Owens Wendt equation.

[Equation 1]

(γ _s and γ _lv represent the surface energy of the electrode and probe (water, diiodomethane), respectively, and d and p have the meaning of dispersive and polar.)

Atomic Force Microscopy (AFM, Digital Instruments Multimode) performed in a 5 x 5 μm2 scan area via ex-situ tapping mode AFM using a SiNx cantilever and a Si tip (42 N / cm 2) for the surface morphology of the DNTT active layer 150 320 kHz, tip radius: 10 nm), and data analysis was performed by emitting electrons near the balance level of the sample using Nanoscope 5.30, XRD, UPS secondary electron emission method.

It was also investigated by operating the DNTT OFET 100 under the negative gate voltage of the DNTT OFET 100. At this time, the source electrode 110 is grounded, and the drain electrode 120 is negatively biased. Electrical parameters characterizing the OFET were obtained at room temperature using the HP4156A equipment in a dark environment under ambient conditions. As a result of measurement using an Agilent 4284 precision LCR meter, a Ci value of 3.70 ± 0.2 nF / cm 2 was calculated for a 600 nm thick parylene insulator gate dielectric layer 170 sandwiched between Au points.

The energy levels of the source electrode 110 and the gate electrode 120 according to the manufactured embodiment have brought a significant difference, which will be described in detail below. In the present invention, a robust and reliable approach to functionally asymmetrically functionalize the thiolated SAM of S / D electrodes 110 and 120 using a simple manufacturing technique without further (electro) chemical desorption procedures was developed.

That is, in the case of the phenyl group of the TP-treated electrode, the surface energy was increased, and the PFBT-treated halogenated phenyl group was decreased in the surface energy.

TP functionalized PFBT functionalized surface characteristics of gold electrode (contact angle and surface energy value) Electrode Contact angles ( ^o ) Surface energy (mJm ^-2 ) Water Diiodomethane Polar Dispersion Total Pristine Au 68 12 6.79 44.19 50.98 TP-functionalized Au 96 56 0.88 30.08 30.96 PFBT-functionalized Au 100 52 0.13 33.80 33.93

2 is a perspective view showing a structure of an organic field effect transistor 100 having a lower contact upper gate structure according to an embodiment of the present invention.

Referring to Figure 2, it can be seen that the parylene (parylene insulator) layer was used as the polymer gate dielectric layer 170, it can be confirmed that the penetration of oxygen and moisture through the DNTT active layer 150 can be prevented.

3 (a), (b), (c), (d), and (e) are graphs showing the output characteristics of DNTT OFETs according to various S / D electrodes, and also FIGS. 4 (a), (b), (c) and (d) are graphs showing transfer characteristics according to gate voltage.

Referring first to FIGS. 3 (a), (b), (c), (d) and 4 (a), (b), (c), (d), the S / D electrodes 110, 120 It can be seen that the drain current and the drain voltage are different depending on the surface condition.

Referring first to FIGS. 3 (a), (b), (c), and (d), symmetrical cases ((a), (b), (c) in FIG. 3) and asymmetry ((d) in FIG. 3) In the case of, (e)), it can be confirmed that the p-type transistor has a good driving state from the fact that it exhibits linear behavior at a low drain voltage and Vd exceeds Vg (gate voltage) in the saturation region.

A high level of linearity at low drain voltage (Vd) indicates ohmic resistance and low contact resistance. Among DNTT OFETs 100, Vd (drain voltage) at TP-S / PFBT-D (see Figs. 3 (e) and 4 (e)) has the lowest IDs (source-drain current) at -30V. Was observed. In addition, the highest IDs were shown in TP-D / PFBT-S (see (d) of FIG. 3 and (d) of FIG. 4). In particular, the output curve of FIG. 3 (d) showed a large separation in Ids values taken at different Vg.

Considering the operating characteristics of the P-type DNTT OFET 100, the hole charge carrier transport in the active channel region from the grounded S electrode 110 toward the negatively biased drain electrode 120 is negatively biased Vg (gate voltage) ), Injection of hole charges from the S electrode 110 to the DNTT active layer 150 and extraction of hole charges from the D electrode 120 may occur.

This may mean that low resistance to TP-D / PFBT-S can naturally induce injection and extraction behavior at the interface.

4 (a), (b), (c), and (d), it is possible to observe the transfer characteristics in the saturation region with respect to the transfer characteristics of the DNTT OFET 100.

From (a), (b), (c), and (d) of FIG. 4, we can extract on / off ratio, threshold voltage (Vth), and parameters for most transistor devices.

Here, the charge mobility μ _FET was determined from Equation 2.

[Equation 2]

The electrical parameters used in Equation 2 are listed in Table 2 below.

 Comparison table of electrical properties according to symmetric asymmetric conditions of DNTT OFET Parameter Pristine S / D TP-S / D PFBT-S / D PFBT-S / TP-D TP-S / PFBT-D μ _FET m ² V ^-1 s ^-1 ) 0.31 ± 0.12 0.23 ± 0.07 0.58 ± 0.19 1.10 ± 0.35 0.18 ± 0.10 V _th (V) -0.92 ± 0.94 -3.72 ± 2.01 -0.27 ± 0.64 0.07 ± 0.01 -2.59 ± 1.21 On / off current ratio ~ 10 ⁴ ~ 10 ⁴ ~ 10 ⁴ ~ 10 ⁴ ~ 10 ³

For asymmetrically generated TP-D / PFBT-S (Example), μ _FET is It was determined to be 0.86 ± 0.23 cm 2 / V / s and more than three times better than Comparative Example 1.

Secondary electron emission experiments on the surface were performed to find the relationship between the μ _FET and the surface potential for the gold electrodes 110 and 120 functionalized with TP and PFBT.

5A and 5B are graphs showing kinetic energy corresponding to secondary electrons, and graphs showing the relationship between work function (WF) and HOMO and LUMO, respectively.

As shown in Fig. 5 (a), the kinetic energy appeared in the order of PFBT functionalization> initial> PT functionalization.

In addition, as shown in Fig. 5 (b), the work functions of the TP-mounted electrode (Au) and the raw electrode (Comparative Example 1) were measured to be 4, 5 eV, and 4.9 eV, respectively. In addition, the PFBT SAM-mounted electrode was measured at 5.4 eV, and the difference from the TP-mounted electrode exceeded 0.9 eV.

This high work function difference was judged to be due to the action of the halogenated terminal. That is, it was judged that this phenomenon occurred because the fluorine group mounted on the surface exhibits high electronegativity.

On the other hand, in the case of the TP electrode, although the phenol group is rich in electron density, it was judged to be due to the relatively electron donating property of the benzene ring.

This property means that the size of the work function WF in the source electrode 110 acts as a barrier for hole injection in the TP electrode, but in the PFBT electrode, it has a much lower charge injection barrier.

On the contrary, in the drain electrode 120, it can be seen that the low work function of the TP electrode lowers the barrier of extraction of the hole carrier to the DNTT active layer 150.

5 (b) shows an energy diagram of charge injection extraction at the interface between the S / D electrodes 110 and 120 and the DNTT active layer 150. The hole injection / extraction barrier can be estimated from the Mott-Schottky model, which defines the injection barrier as the difference between the effective work function (WF) of the electrode and the HOMO level of DNTT.

 In the initial Au case (Comparative Example 1), a 0.5 eV injection barrier was obtained from the S electrode 110 to the p-type DNTT active layer 150. After TP deformation of the S electrode 110, the effective WF is reduced to 4.5 eV, resulting in a high barrier of 0.9 eV when injecting holes into the DNTT layer. Conversely, the PFBT deformation of the S electrode 120 reduced the hole injection barrier further to 0 eV since the dipole direction of the PFBT SAM 140 is opposite to that of the TP SAM.

In addition, Vth (threshold voltage) was considered as another parameter in the present invention.

Vth is affected by the intrinsic electric field generated by the permanent dipoles of the SAMs 130 and 140 and the electrochemical reaction between the surface functional groups and the semiconductor molecules. Early studies of electrode surface chemistry show that a surface with strong affinity for electrons preferentially attracts electrons from the semiconductor side, balancing charges and injecting extra holes that actively move Vth. Therefore, it can be said that adjusting the surface potential of the electrodes 110 and 120 is important for changing the charging and electrical performance of the OFET 100.

As described above, in the present invention, it has been described by specific matters and limited embodiments and drawings, which are provided to help a more comprehensive understanding of the present invention, and the present invention is not limited to the above embodiments, and the present invention Various modifications and variations are possible from those skilled in the art to those skilled in the art.

Therefore, the spirit of the present invention is limited to the described embodiments, and should not be determined, and all claims that are equivalent to or equivalent to the claims, as well as the claims described below, will belong to the scope of the spirit of the present invention. .

100: organic semiconductor transistor 105: glass substrate (glass substrate)
110: source electrode 120: drain electrode
130: TP (thio phenol) structure 140: PFBT (2,3,4,5-pentafluorobenzene thiol)
150: organic active layer (DNTT, dinaphtho [2,3-b: 2 ′, 3 ′ '-f] thieno [3,2-b] thiophene)

Claims (9)

In the organic field effect transistor having a combined structure of an asymmetric organic semiconductor layer and an electrode for charge injection and extraction of the organic semiconductor,
Glass substrates;
A source electrode and a drain electrode formed on the glass substrate;
Self-assembled monolayers (SAMs) in the form of 2,3,4,5-pentafluorobenzene thiol (PFBT) formed on the source electrode;
Thiophenol (TP) type self-assembled monolayers (SAMs) formed on the drain electrode;
A parylene insulator, a polymer gate dielectric layer for preventing the penetration of oxygen and moisture into the source and drain electrodes; and DNTT (dinaphtho [2,3-b: 2 ′, 3 ′ '-f] thieno [3,2-b] thiophene) polymer and single molecule active layer including an active layer; And
A gate electrode formed on the polymer gate dielectric layer;
Characterized in that it has a bottom contact-top gate structure, including
Organic Field Effect Transistor delete According to claim 1,
The source electrode and the drain electrode, characterized in that formed of a gold (Au) material
Organic Field Effect Transistor According to claim 1,
The self-assembled monolayer chemically adsorbs to the source and drain electrodes to induce the movement of the fermi level and to increase the metal work function by inducing dipoles toward the metal surface. Or can contribute to reduction
Organic Field Effect Transistor According to claim 1,
The modification of the self-assembled monolayer is
Characterized in that it can control the charge injection and extraction between the active layer and the electrode interface
Organic field effect transistor. In the method of manufacturing a transistor comprising an asymmetric organic semiconductor layer and an electrode for charge injection and extraction of the organic semiconductor,
Depositing a source electrode and a drain electrode by a method of thermal deposition on a glass substrate (s10);
Chemically adsorbing 2,3,4,5-pentafluorobenzene thiol (PFBT) type self-assembled monolayers (SAMs) on the source electrode (s20);
Chemically adsorbing thiophenol (TP) -type self-assembled monolayers (SAMs) onto the drain electrode (s30);
Active layer of DNTT (dinaphtho [2,3-b: 2 ′, 3 ′ '-f] thieno [3,2-b] thiophene) using organic molecular beam deposition system (OMBD) Forming a step (s40);
Forming a polymer gate dielectric layer on the DNTT active layer (s50): and
Forming a gate electrode on the polymer gate dielectric layer (s60);
Characterized in that it has a bottom contact-top gate structure, including
A method of manufacturing a transistor including an asymmetric organic semiconductor layer and an electrode for charge injection and extraction of an organic semiconductor. The method of claim 6,
The TP type self-assembled monomolecular film is characterized by increasing the surface energy of the drain electrode.
A method of manufacturing a transistor including an asymmetric organic semiconductor layer and an electrode for charge injection and extraction of an organic semiconductor. The method of claim 6,
The self-assembled monolayer of PFBT type,
Takes the form of a halogenated phenyl group,
Characterized by reducing the surface energy of the source electrode
A method of manufacturing a transistor including an asymmetric organic semiconductor layer and an electrode for charge injection and extraction of an organic semiconductor. The method of claim 6,
The asymmetrically functionalized S / D electrode is
Improve the charge mobility,
Characterized in that it is possible to improve the electrical properties of the organic field effect transistor by lowering the contact resistance and the channel resistance.
A method of manufacturing a transistor including an asymmetric organic semiconductor layer and an electrode for charge injection and extraction of an organic semiconductor.

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