A method of obtaining a thin-film semiconductor devices based on organic compounds

 

Usage: semiconductor technology. The essence of the invention: production method of a thin-film semiconductor devices based on organic compounds containing electrode node electrodes in contact with the organic semiconductor material, the anode in the electrode unit is designed as a two-layer structure, the first layer which is a conductive or semiconductor material, or combination thereof, deposited on a substrate, and the second layer is a conductive polymer with a work function higher than the work function of the material in the first layer. The third layer consisting of an organic semiconductor material and forming an active material of the device, is applied over the anode, and the cathode is made of a fourth metal layer deposited on the third layer. In a preferred embodiment, a metal with low work function is used in the first layer, doped conjugated polymer, in particular PEDOT-operates - in the second layer, while the cathode can be formed of metal similar to that used in the first layer. The invention is used when receiving electrode node in thin film diode on the basis of organic compounds or transisto what oterom combines the best properties of charge injection with a high conductivity, with line structuring a width of about 1 micron. 2 C. and 14 C.p. f-crystals, 15 ill.

Technical FIELD the Invention relates to a method for producing electrode in a thin-film semiconductor device based on organic compounds, in which a semiconductor device, in particular, is a rectifier diode with a high coefficient of straightening or thin-film transistor based on carbon or hybrid transistor on organic and inorganic thin films, and the method of production is made on the basis of organic compounds, thin-film rectifying diode with a high coefficient of straightening, according to which the rectifier diode includes a first layer and a second layer provided on the first layer, together forming the anode of the rectifying diode, the third layer of semi-conductive organic material provided over the anode, forming an active semiconductor material of the diode, and the fourth metal layer provided structured or unstructured on top of the third layer forming the cathode of the rectifying diode.

The invention concerns, in particular, changes in the injection properties of the electrode in templene thin film rectifying diodes based on organic compounds.

PRIOR art IN published international application WO 98/53510 (Cambridge Display Technology, Ltd.) this article describes a method of structuring an organic light-emitting device having an organic light-emitting layer, the underlying electrode layer. The device also contains other structured electrode layer, which forms the anode of the device. The specified anode layer should inject carriers of positive charge in the active organic semiconducting material and is formed as a double layer of indium oxide-tin (Reis)(TO), which is transparent, and polyethyleneoxide doped polystyrenesulfonate (PEDOT-PSS)(PEDOT-PSS), which is in contact with the active material. Although the Reis is the preferred contact material of the anode, can be used an alternative conductive materials, including various doped metal oxides or metals, such as gold or its alloys. A conductive polymer for injection of carriers of positive charges can in this case be polyethyleneoxide doped with polystyrenesulfonate (PEDOT-PSS), or the doped polyaniline, or combinations thereof. It is also preferable to work exit some of its area, and thus, the substrate bearing an anode layer, in this case, the glass sheet must also be transparent. The use of transparent, translucent, or at least structured electrode is undoubtedly one of the requirements in the light-emitting or photovoltaic devices, as follows from a European patent application EP 0901176 A2 (Cambridge Display Technology Ltd.), where the anode layer 1 in the form of the Reis applied to the template or drawing on a transparent substrate and covered PEDOT-PSS for contacting the active semiconductor, i.e., organic light-emitting layer.

As you can see, the anode material, i.e., the conductor used in the anode in combination with a conductive polymer, in any case must be transparent or translucent. However, a common problem associated with the use of, for example, transparent oxides, which are not as effective conductors, such as metals, and precious metals, like gold and its alloys, in the anode, because these materials have a negative impact on covering the conductive polymer, as will be discussed below.

In addition, from a European patent application EP 0716459 A2 (Dodabalpur and al. ) known thin-film trainee power on/ off, than traditional TTOS. As the materials described in this publication for the electrodes, the source/drain and the control electrodes, uses gold or in the case of bimetallic layer is chromium and gold. The choice of electrode materials may also be problematic in combination with thin-film semiconductor-based organic compounds, as in this case.

Article M. Granstrom and al. "Laminated fabrication of polymeric photovoltaic diodes", Nature, Vol. 395, pp.257-260 (1998) considered the photovoltaic diode with a double layer of semi-conducting polymers. Fotovozbuzhdenii electron transfer between donor and acceptor molecular semiconductors provides an effective way of generating charge after photoabsorption and can be used in photovoltaic diodes. But efficient separation of charge and migrate to the collecting electrodes are problematic, because the absorbed protons should be close to the donor-acceptor generously, while at the same time requires good coupling of donor and acceptor materials in the respective electrodes. A mixture of acceptor and donor semiconducting polymers can give Vaserstein patterns, which in some frame is motivat two-layer polymer diodes, where the acceptor material is a fluorescent lanproton poly(paraphenylenevinylene) (MEH-CN-PPV) with a small number of derived polythiophene (RORT). The acceptor layer is in contact with the electrode and deposited on a glass substrate. The acceptor layer laminated together with a donor layer of RORT doped with a small amount of MEH-CN-PPV, which is applied by centrifugation or on the substrate of indium oxide-tin (Reis), or glass coated with poly(ethylenedioxythiophene), alloyed with polystyrenesulfonate (PEDOT-PSS). To ensure low contact resistance of a thin layer of gold is thermally evaporated on the glass substrate before applying centrifugation PEDOT material. Because Granstrom and al. describe the photoelectric diode, it is obvious that they are not associated with high coefficient straightening, as it would be desirable in switching diodes, and is missing the required difference in the values of the work function of the cathode, although all materials considered for the anode, including the Reis, PEDOT and gold, have a high value of the work function, which is in the range from 4.8 eV for the Reis to much above 5 eV for PEDOT and gold, with values output for the last two allauto, cause poor quality conductive polymer thin film deposited on the polymer film often contains holes that are invalid when films are used in a layered structure. In addition, gold is an expensive material, but, apparently, Granstrom and al. chose gold because of its transparency and high values of the work function, the corresponding value for PEDOT-PSS.

In the switching semiconductor devices with diode structures it is desirable to have a high coefficient of straightening the latter, and it is also desirable that the contact surface between the electrode and the semi-conducting polymer provided efficient injection of charge, but this last feature does not apply to the collecting electrodes are anodes, in a photovoltaic device based on organic semiconducting materials.

It is known that the contact surface between the conductive and semi-conductive polymer has better properties in terms of charge injection. For example, conductive polymer based on poly(3,4-ethylenedioxythiophene) (PEDOT) has a very high output, which makes it applicable as the anode is lead PEDOT limits the characteristics of the components due to the very high series resistance. This is seen especially clearly has negative consequences when the electrodes are structured lines with a width of about 1 micron. However, it is believed that such components must be critical for realizing the storage elements of high density for use in memory modules, based on the polymer in the form of a memory material, provided that it will be possible to achieve the desired high speed of data reading. It will, however, depend on the ability of the highly conductive electrodes for storage of items that can be obtained by means of microminiaturization.

Disclosure of the INVENTION the present invention is therefore the task of developing methods for producing electrode for use in organic semiconductor devices with a combination electrode of the best properties of charge injection with a high conductivity. In addition, the object of the invention is to provide a method which allows to obtain the electrode of the specified type with line structuring a width of about 1 micron. Another objective of the present invention is to develop a method of producing an organic thin-film diodes with a high coefficient of straightening is carried out by the first method according to the invention, under which form the first layer of base metal or inorganic semi-conducting material or combination of base metal and inorganic semiconducting material, put the second layer of conductive polymer on the first layer, and the specified conductive polymer selected from polymers with a work function whose values are equal to or exceed the value of the work function of the first layer, so that the actual work output of the electrode in any case becomes equal to the work function of the selected conductive polymer, and forming an electrode in the organic semiconductor device with the possibility of contacting the second layer with at least part of the active semiconductor material in a semiconductor device. The problem is solved also by the fact that according to the second method according to the invention, put the first layer in the form of a base metal or inorganic semiconductor, or a combination of base metal and inorganic semiconductor on the insulating substrate, and said first layer is applied to structured or unstructured, covering at least part of the substrate, and is applied over the first layer, the second interconnection is a polymer selected as the conductive polymer with the working function, equal to or greater than the work function of the first layer, resulting in a work function of the anode in any case becomes equal to the work function conductive polymer.

Preferably, the first layer was made of such metals as calcium, manganese, aluminum, Nickel, copper or silver. Also preferably, the inorganic semiconductor material of the first layer was a silicon, germanium or gallium arsenide.

It is expedient according to the invention, that the second layer was applied in the form of a dispersed layer of dispersant or as a layer of dissolved material from a solution or alternative put by a method of application of the melt.

According to the invention is preferable as a conductive polymer in the second layer to use doped conjugated polymer as a conjugated polymer to use such polymers as poly(3,4-dioxyethylene) (PEDOT), a copolymer comprising the monomer 3,4-dioxyethylene; substituted polythiophene; substituted polypyrrole; substituted polyaniline or their copolymers, whereas alloying agent for the conjugated polymer is preferably poly(4-styrelseledamot) (PSS).

In a preferred embodiment, SF) (PEDOT), doped poly(4-styrelseledamot) (PSS).

In a variant, according to which only a portion of the substrate covered by the anode, may optionally be applied to the third layer over at least part of the substrate that is not covered by the anode.

According to the invention, it is preferable to select an organic semi-conductive material in the third layer among conjugated polymers or crystalline, polycrystalline or microcrystalline and amorphous organic compounds, and in the case of selection of a conjugated polymer, the latter is preferably chosen from among such polymers as poly(2-methoxy-5-(2'-ethylhexyloxy)-1,4-phenylenevinylene) (MEH-PPV) or poly(3-hexylthiophene) (rsnt).

Finally, according to the invention, it is preferable to choose the fourth metal layer among the metals which have a lower work function than the anode, and then particularly preferable to select a metal fourth layer of metal selected for the first layer, but aluminum, in particular, in any case can be selected as the fourth metal layer.

Hereinafter the invention will be described in more detail with reference to examples of the polymer-containing diodes with a high coefficient of straightening obtained according spacevideo polymer, in particular PEDOT-PSS.

Fig.1B is an example of the structure of the conjugated polymer belonging to the class of polythiophenes, in particular rsnt.

Fig.1C is an example of the structure of the conjugated polymer belonging to the class of polyphenylenevinylene, in particular MEH-PPV.

Fig.2A is a first variant of the diode made according to the method of the present invention.

Fig.2B is another variation of the diode made according to the method of the present invention.

Fig.2C is a cross section on line a-a of the diode shown in Fig.2B.

Fig.3A - volt-ampere characteristics of the diode-prototype obtained under the two different technological regimes.

Fig.3V - current-voltage characteristics of the diode made by the method according to the present invention, and a diode made according to the method of the prior art.

Fig.3C - volt-ampere characteristic of a diode made by the method according to the present invention, and a diode made according to the method of the prior art.

Fig.3d current-voltage characteristics of the diode made by the method of the present invention, and a diode made according to the method of the prior art.

Fig. 3E - volt-ampere characteristics the prior art.

Fig. 3f - dependence of the rectification of the voltage of a typical diode made by the method according to the present invention.

Fig. 4 is a graph in semi-logarithmic coordinates volt-ampere characteristics of the diode in the prior art and diode according to the present invention with the insert showing the ratio of rectification as a function of voltage for a diode according to the present invention.

Fig.5 - forward current density of 100 μm2diode according to the present invention in scale with the current density of the diode of the invention of Fig.4 inset shows a semi-log graph of the current-voltage characteristics 100 μm2the diode.

Fig. 6 - forward current density of 1 μm2diode according to the present invention in scale with the density of the forward current of the diode in Fig.2 insert a line graph showing current-voltage characteristics of 1 μm2the diode.

The BEST VARIANT of the INVENTION, the Present invention can be used to implement electrode on the organic semiconductor in thin film electronic equipment. In the anode conductive polymer is used as a conjugated polymer, in which injected the Merom is poly(3,4-ethylenedioxythiophene) (PEDOT) (PEDOT), doped poly(4-styrelseledamot) (PSS) (PSS). The specified type conductive polymer in the following will be denoted PEDOT-PSS (PEDOT-PSS). In Fig.1B shows the structure of a semiconducting conjugated polymer belonging to the class of polythiophenes, namely poly(3-hexylthiophene) (rsnt), and Fig.1C shows the structure of another semiconducting conjugated polymer belonging to the class of polyphenylenevinylene, namely poly(2-methoxy-5-(2'-ethylhexyloxy)-1,4-phenylenevinylene) (MEH-PPV). The use of these materials is well known in organic semiconductor technology.

In Fig.2A shows a first variant of the diode in thin-film electronic equipment made by the method according to the present invention. On a substrate 1, which is made of insulating material, such as glass or silicon, where the surface is selectively oxidized with the formation of silicon dioxide on the template is applied to an electronic conductor with high conductivity, such as metal in the form of thin strips 2, which constitute the first layer 2 in the diode. The metal may be selected from among such metals as calcium, manganese, aluminum, Nickel, copper or silver. Since layer 2 is part of the anode of the diode, pre the of technology. However, these noble metals are more or less chemically inert and, at least when it comes to gold, also tend to migrate into adjacent layers. Gold should be avoided for the reasons given in the introduction. Therefore, according to the invention should be selected metal with a low work function, such as copper, aluminum or silver, which provides good adhesion to lying on top of the second layer 3, which is made of conductive polymer with high value output. According to a preferred variant of the invention the second layer 3 uses a conductive polymer in the form of PEDOT doped PZT. In Fig. 2 the specified second layer 3 of PEDOT-PSS applied to the template conformal with the first layer 2, and a combination of metal/PEDOT-PSS in this case forms the anode 2, 3 diode. Above the anode 2, 3 further covered with a third layer 4 of semi-conducting polymer. According to a preferred variant of the invention, the third layer is made from semi-conducting polymer, mainly such as poly(2-methoxy-5-(2'-ethylhexyloxy)-1,4-phenylenevinylene) (MEH-PPV). Can also be used other semi-conducting polymers, such as poly(3-hexylthiophene) (rsnt). Next, on top of tons of the metal, with an acceptably low value of the work function. As metal can be used, in particular, aluminum, however, the cathode may be made from other materials with comparable electronic properties, such as indium oxide-tin (Reis). The formed diode in Fig.2A has a layered structure with the anode, is made of several structured strip electrodes, and is characterized by active area, i.e., the semiconductor layer 4 size of about 1-100 μm2.

In Fig.2B shows a diode structure where a metal layer on the anode 2,3 is applied not on the template, for example, on one half of the substrate 1. Conductive material 3, which is preferably used PEDOT-PSS, is applied mostly on top of the metal layer 2, thereby forming the anode 2, 3 adapted for use in high-power diodes. The active material 4 in the form of semi-conductive material is applied repeatedly over the anode 2, 3 and the cathode 5 in the upper part, made for example from aluminum, imposed in the form of two parallel wide strips with the formation of the fourth layer in the diode structure. In Fig.2C shows a cross-section of the diode according to Fig.2B along the line a-a in the longitudinal direction through the cathode strip 5. Usually as a diode, pokazanno the mm2.

In each case, variations of the diodes according to Fig.2 correspond to the organic thin-film diodes on the basis of the layered structure design.

In Fig.3A presents the current-voltage characteristics known from the prior art device in a flat geometry, made with PEDOT between copper electrodes, where the curve with shaded circles shows the characteristics of PEDOT caused by centrifugation at 4000 rpm, and the curve with Nestorianism mugs features PEDOT caused by centrifugation at 1000 rpm Distance between copper electrodes is approximately 1 mm, and the characteristic is linear, which is typical ohmic resistance.

In Fig. 3b presents the current-voltage characteristic expressed by direct current in a conducting direction and the reverse current in the conductive direction of the diode is known from the prior art (solid line), and a diode made according to the method of the present invention (line with circles/dots). Known diode made with RST as a semiconductor material, deposited by centrifugation at 600 rpm using 5 mg/ml solution and placed between the copper anode and aluminum cathode s a solid line. Diode made by the method according to the present invention has an anode 2, 3, made of two layers of copper and PEDOT-PSS as a conductive polymer deposited by centrifugation at 3000 Rev/min Active semi-conducting material RST applied by centrifugation at 600 rpm at a rate of 5 mg/ml solution, and the cathode is made of aluminum. In this case, the characteristic is determined by two series of measurements and, as can be seen from Fig.3b, the results are virtually identical. The corresponding series of measurements differ curves with Nestorianism or shaded circles, respectively. The top two, almost identical curves show the current in the forward direction, whereas the lower curves show the current in the opposite direction. The difference compared with the diode, made in the traditional way, is obvious.

Accordingly, in Fig.3C presents the current-voltage characteristics of the diode according to the prior art and diode made according to the present invention. Diode according to the prior art uses MEH-PPV caused by centrifugation at 800 rpm at a rate of 5 mg/ml solution, as a semiconductor material, located in the layered case is represented by the curve with shaded circles. Diode obtained by the method according to the present invention, uses the same organic semiconductor material, deposited in similar conditions, but the anode is formed from a double layer of copper with PEDOT-PSS deposited by centrifugation at 4000 rpm, and the cathode is made of aluminum. Characteristic in this case is shown in the form of a curve with Nestorianism circles, and the difference between the known characteristics of the component and the component made by the method according to the present invention, is again obvious.

In Fig. 3d is similar to the variant according to Fig.3C shows the current-voltage characteristics of the same components, where the conductive material and the active organic semiconductor material is applied exactly in the same conditions, respectively, but in both cases, the anode is made of aluminum.

In Fig. 3E presents the current-voltage characteristics of the diode according to the prior art and diode made by the method according to the invention. Known diode uses an active material consisting of MEH-PPV caused by centrifugation at 600 rpm at a rate of 5 mg/ml and placed in a layered structure between the Nickel anode and an aluminum cathode. Feature in either, uses the anode, is made in the form of a double layer of Nickel and PEDOT-PSS deposited by centrifugation at 4000 rpm, while the active material is MEH-PPV caused by centrifugation at 600 rpm at a rate of 5 mg/ml solution, and the cathode is aluminum. Characteristic in this case shows a curve with Nestorianism circles.

Finally, in Fig.3f presents the coefficient straightening typical diode made by the method according to the present invention, and with the anode in the form of a double layer si/PEDOT-PSS, the active organic semiconductor in the form of MEH-PPV and aluminum cathode. As you can see, with voltages of 3 and above is high coefficient straightening of the order of 106-107.

According to the present invention, the anodes in the form of a double metal layer or semiconductor layer or layers of semiconductor and metal, formed under the layer of conductive polymer in the form of PEDOT-PSS will be to improve the conductivity. Metal and semiconductor in the anode can be si or Al, have a low work function, but in combination with PEDOT anode shows essentially high values of the work function PEDOT. At the same time, the combination of metal and PEDOT improves conductivity ANO the functions, providing an injection that is free from the problem of holes. If the anode is made from metal, the current flow will be limited by contact, but using PEDOT-PSS cause restriction of current flow associated with the volume. When using the anode metal/PEDOT-PSS, as shown in Fig.3f, you can get diodes with a coefficient of straightening up to seven orders of magnitude. The main advantage, which is achieved by using the anode metal and a conductive polymer, is the ability to structure the anode. The use of metal under PEDOT gives higher conductivity of the electrodes as compared to a conductive polymer. Even in the case of structured electrodes with a line width of about 1 micron high current density can be achieved in combination with the highest properties of charge injection. This can be used to implement the storage elements in polymer memory devices with a high density data storage, and it becomes possible to achieve high read rates due to the highly conductive electrodes. At the same time, the storage elements may be implemented with a line width of about 1 micron appropriate structuring of the metal/polymer is brilliant polymer should be ohmic.

Below with reference to corresponding figures of the drawings examples of diodes made by the method according to the present invention, and the corresponding current-voltage characteristics.

An example of the Development of electronic devices using polymers demanded a significant investment, most of which was aimed at the creation of field-effect transistors and diodes in the simulation of silicon electronic devices. Among diodes as light emitting diodes and photodetector diodes constitute the main object of research; both of them used a transparent electrode. However, the diode-based organic compounds with high rectification is the most popular in electronics. In order to get the diodes on the basis of semiconducting polymers with high rectification, necessary materials, which provide efficient injection of charge through the polymer under forward bias and a much smaller under reverse bias. Usually this is achieved by using materials that are consistent energy level or form a low potential barriers to the HOMO (Highest occupied molecular orbital) and LUMO (Lowest unoccupied molecular orbital) levels PNIA low current, which provides a high coefficient of straightening. But this position fails to consider the energy levels. Surface properties of the partition and the quality of the polymer film formed on this metal can define the properties of the diode; often polymeric film deposited by centrifugation on inert materials such as gold, has holes that are invalid, if you want to vaporize the upper electrode on top of the polymer film in a layered structure. On the boundary surface conductive polymer /semi-conducting polymer has a tendency to good adhesion. It was found that the oxidized conductive polymer poly(3,4-ethylenedioxythiophene), doped poly(4-styrelseledamot) (PEDOT-PSS), has a high value of the work function of 5.2 eV, which enables efficient injection of holes into the light-emitting diodes (LED"s) (LEDs) or reservoirs in the photodiodes. However, the higher resistance PEDOT-PSS compared to traditional metals could jeopardize the diode characteristic in structured thin lines due to the voltage drop at high currents. To solve this problem under the polymer using a metal layer. Any metal MoA (fm) with work function PEDOT (fPEDOT). Since it is known that noble metals such as gold and platinum, which are typically used in light-emitting diodes organic compounds that have a negative impact when used in combination with PEDOT, it is preferable to use base metals with high conductivity. Under the "base metals" refers to metals with electrochemical potential of less than 1 Century

During testing diodes made from several metals (Al (4.2 eV), Ad (4.3 eV), si (4.5 eV)), in all cases, the current holes, which was the current, limited contact, was changed to the current, limited displacement, when the layer PEDOT-PSS was used between the anode metal and semi-conducting polymer MEH-PPV (poly(2-methoxy-5-(2 xeloxa)-1,4-phenylenevinylene). To study the electrical properties of the diodes with different active zones of copper was chosen as the underlying layer, in particular, due to its good stability and characteristics of the etching. It was shown that the surface of the partition C/PEDOT-PSS is ohmic contact resistance rwith~7 Ohm/. The ohmic nature of the interface si/PEDOT-PSS is vanima C/PEDOT-PSS was measured using a flat geometry to provide a copper surface, such surfaces used for diodes.

The diodes were designed in a layered structure using C/PEDOT-PSS as the anode and Al as the cathode (f=4.2 eV). They mount on glass or Si with 2 μm-th thickness of the oxide substrate, as shown in Fig.2A-2C. In Fig. 2B shows the structure for a typical diode typically 6-10 mm2the active area. For these diodes copper layer is applied by evaporation to a preferred thickness of 200 nm on one half of the substrate. Layer PEDOT-PSS (Bayer AG, Germany) with a thickness of 80 nm is applied by centrifugation of the solution of water with 30% isopropanol, filtered using a 1 μm porous glass filter. PEDOT-PSS is applied on the pattern of conformal copper and then subjected to heat treatment for 5 min at 120oC. it is Noted that PEDOT-PSS solution interacts with the copper oxide, vetralla the surface of the si film, which facilitates the formation of a contact. The layer of semi-conductive polymer is applied by centrifugation using polymer MEH-PPV dissolved in chloroform at a concentration of 5 mg/ml, to a thickness of 190 nm. The second electrode of Al is applied by vacuum evaporation through a shadow mask defining the active area. For diodes with 1 and 10 μm2the active area of the generation of the si layer (200 nm thick) with PEDOT-PSS (80 nm thick) in the upper 500 μm long strips with a width of 1 and 10 μm, followed by heat treatment. Specified structured substrate cover MEH-PPV by centrifugation, sprayed on top of Al and structure in stripes like si, in order to get the intersection of 1 and 100 μm2. The design of the diode of this type is shown in Fig.2B.

Volt-ampere characteristics of the two similar diodes made using polymer MEH-PPV, is shown in Fig.4, which shows a semi-log graph of the current-voltage characteristics of MEH-PPV-containing diode using a copper anode (nestorienne circles), and the like MEH-PPV-containing anode, using C/PEDOT-PSS anode (shaded circles). On the graphic inset shows the semi-log graph of the coefficient of straightening against voltage for a diode with a si/PEDOT-PSS-anode. The measurements were carried out using a semiconductor accurate analyzer settings in the dark area type Hewlett Packard 4156A. You can note the difference in the form of volt-ampere characteristics resulting from the introduction PEDOT-PSS layer. Due to higher value of work function PEDOT-PSS (5.2 eV) compared to si (4.5 eV) energy barrier for hole injection from PEDOT-PSS to MEH-PPV is f~0.1 eV. This is much less than the energy barrier for daroca different. Copper is limited by contact current mode; in this mode, a low injection values of current density are small and the spatial charge effects can be neglected. With the introduction of a thin layer PEDOT-PSS can be obtained transition to a limited displacement current mode, where direct current is caused mainly positive media coming from C/PEDOT-PSS electrode. Diodes si/PEDOT-PSS/MEN-PPV/Al introduce the function J(V) with three areas of limitations, and J is the current density. The current from 0 to 1 is at the level of industrial noise; has a place for a small charge. This condition is caused by the difference in the values of the work function of the electrodes (PEDOT-PSS and Al ~ 1 eV) that generates an internal potential in the polymer layer and prevents hole injection. First, you need to bring a specified voltage to inject charge. Between 1 and 2 In the current varies exponentially and its value increases by five orders of magnitude. Specified sharp increase is a property of the surface section PEDOT-PSS/MEH-PPV with its low energy barrier. At voltages above 2 V current becomes dependent on the characteristics of the transfer of the MEH-PPV layer. On the graphic insert of Fig. 4 predstavlja the quotient of the direct current to the reverse current. At a voltage of 3 In the ratio straightening increases by six orders of magnitude and seven orders of magnitude at a voltage of between 4 and 8 Century At voltages higher than 8 In the injection of holes from the Al to the MEH-PPV increases the reverse current, reducing the value of the coefficient of straightening.

In Fig. 5 shows the forward current density of 100 μm2diode according to the invention and with C/PEDOT-PSS/MEH-PPV/Al structure (shaded triangles) in scale with the forward current density (shaded circles) diode according to the invention, as shown in Fig.4, while the graphic insert presents a semi-log graph of voltage-current characteristics 100 μm2the diode.

C/PEDOT-PSS/MEN-RDD/Al diodes with 100 μm2the active zone is represented in a similar form of volt-ampere characteristics of direct current, as can be seen in the inserted graph in Fig. 5. In order to compare the volt-ampere characteristics of both diodes in Fig.5 shows a graph of current density as for the diode with Fig.4 (8 mm2) and diode with 100 μm2. The deviation in absolute value of the current can be explained by the difference of thickness for different diodes. Carrying out scaling is justified.

In Fig.6 presents the density direct tacuati) in scale with the forward current density (shaded circles) diode according to the invention with Fig.4, while the graphics on the insert presents a line graph of the current-voltage characteristics of 1 μm2the diode.

However, for a diode with a specified size, the level of current is quite low, close to the noise level, as can be seen in the inserted graph in Fig. 5. Volt-ampere characteristics for the current density as a diode with 1 μm2active area, and the diode 8 mm2the active area is depicted on the chart. Function J(V) for a smaller diode is depicted in the diagram to twenty volts. You can see that its characteristics and the form is not very well correlated with a large diode. In these small diodes expansion area only ten times greater than the thickness of the layers and is expected influence of the edge of the fields, even more important may be the appearance of irregularities, causing an error when any geometric estimates.

Research in the electrical property of the transfer of conjugated polymers and units of the polymer/metal started relatively recently. The first attempt at modeling PPV-containing diodes was based on the model of Fowler-Nordheim describing the tunneling process in the diode. You can get the approximated values of the heights of the barriers and the energy levels of the polymers. Then there was prilo proposed, so that when current flows through limited contact current could be determined polarization forces taking into account the effect of the pendant causing the trapping of carriers at the interface. The specified capture results in increasing the height of the energy barrier, reducing the injection stream. It was concluded that the presence of insulating material, free from traps, can increase the charge injection. If PEDOT-PSS has been shown that in the process of applying this material by centrifugation takes place stratification PEDOT and PSS. PSS is an insulating material, and found that it forms a thin layer completely covering the surface PEDOT film. Specified a thin layer cannot collect the charges from the electrode, which may explain the improvement of the injection of charge carriers from PEDOT. A limited amount of current from MEH-PPV was studied and described by several research groups. It was found that the high field MEH-PPV represent spatial charger current limitation and that the mobility of carriers depends on the applied electric field. In this case, the behavior is similar, since the current does not depend on the accuracy of V2because dependent on the field all the of models, developed by P. N. Mugatroyd (J. Phys.D., Vol.3, 151 (1970)), combines the spatial dependence of the charging constraints with a variable mobility in the same equation. Using these models it is possible to evaluate the data obtained here, the graphical image of the high voltage current in the format function JL3regarding (VL)0,5where J is the current density, L is the thickness of the polymer, and V is the applied voltage minus the contact potential difference of the diodes. For the present invention that provides the coordination of data and gives similar values for polymers0and E0, i.e., the zero field mobility and the characteristics of the fields, respectively.

So, in the present invention disclosed diode for polymers with a high coefficient of rectification using two metals with low work function, where the anode is modified by the introduction of a conductive polymer layer PEDOT doped PZT. This surface modification can go from disconecting limited by the size of the contact current to vasocongestion limited displacement current. Stratification PEDOT/PSS may facilitate charge injection elimination ku is of diodes, structured on the micrometer level. The above diodes can be used for active microelectronic devices such as switching diodes and switching transistors, as well as electrically addressable thin-film storage devices of high density, such as passive matrix.

Moreover, considered the electrode can also be used as an electrode in the organic thin-film transistors, for example, of the type discussed in the above patent application EP 0716459 A2, for replacement of standard electrodes based on gold or gold, combined with another metal.

Claims

1. The method of forming an electrode for semiconductor devices based on organic compounds in a thin film, in particular, to a rectifier diode with a high coefficient of straightening or thin-film transistors based on organic compounds, or hybrid thin-film transistors based on organic/inorganic compounds, wherein forming the first layer of the base metal, or inorganic semiconducting material, or a combination nelagoney layer, moreover, the specified conductive polymer selected from polymers with a value of work function greater than the value of the work function of the first layer, due to which the actual value of the work function of the electrode in any case becomes equal to the value of the work function of the selected conductive polymer, and forming an electrode in the semiconductor device based on organic compounds with the possibility of a contact between the second layer and at least part of the active semiconductor material in a semiconductor device.

2. The method of obtaining the rectifier diode on the basis of organic compounds with a high coefficient of straightening in a thin film, whereby forming the first layer and a second layer provided on the first layer, together forming the anode of the rectifying diode, is formed over the anode of the third layer of organic semiconducting material forming the active semiconductor material of the diode, and is formed over the third layer fourth layer of metal, provided structured or unstructured with the formation of the third layer of the cathode of the rectifying diode, wherein the first layer is applied in the form of nebago semiconductor on the insulating substrate, moreover, the first layer is structured or unstructured, and covers at least part of the substrate, and the second layer is applied in the form of a conductive polymer is completely or partially covering the first layer, and the specified conductive polymer is selected in the form of a conductive polymer with a value of work function greater than the value of the work function of the cathode, resulting in the value of the work function of the anode of the rectifying diode in any case becomes equal to the value of the work function conductive polymer and a large work function of the cathode.

3. The method according to p. 2, characterized in that as the base metal of the first layer using calcium, manganese, aluminum, Nickel, copper or silver.

4. The method according to p. 2, characterized in that the inorganic semiconducting material of the first layer using silicon, germanium or gallium arsenide.

5. The method according to p. 2, characterized in that put the second layer by sputtering from a dispersant or precipitation of dissolved material from a solution.

6. The method according to p. 2, characterized in that the second layer is formed by applying the melt.

7. The method according to p. 1, wherein as the conductive polymer in the second layer use legerov from among poly(3,4-dioxyethylene) (PEDOT), the copolymer comprising the monomer 3,4-dioxyethylene, substituted polythiophenes, substituted polypyrroles, substituted polyanilines or their copolymers.

9. The method according to p. 7, characterized in that as alloying materials for the conjugated polymer used is poly(4-styrelseledamot) (PSS).

10. The method according to one of the p. 7 or 8, characterized in that the doped conjugated polymer used is poly(3,4-ethylenedioxythiophene) (PEDOT), doped poly(4-styrelseledamot) (PSS).

11. The method according to p. 2, characterized in that in the case when only a portion of the substrate covered by the anode, at least a portion of the substrate not covered by the anode additionally put the third layer.

12. The method according to p. 2, characterized in that the organic semiconductor material in the third layer using conjugate polymer or crystalline, polycrystalline, microcrystalline and amorphous organic compounds.

13. The method according to p. 12, characterized in that the conjugated polymer in the third layer using poly(2-methoxy-5-(2'-ethylhexyloxy)-1,4-phenylenevinylene) (MYUNG-PPV) or poly(3-hexylthiophene) (rsnt).

14. The method according to p. 2, characterized in that as the fourth metal layer used in the .14, characterized in that for forming the fourth and first layers use the same metal.

16. The method according to p. 15, characterized in that as the fourth metal layer using aluminum.

 

Same patents:
The invention relates to a technology for thin (0.1 ám) of magnetic films (TDM) using the method of ion implantation of magnetic elements in the substrate material and can be used in microelectronics and computer science, in particular, for the manufacture of magnetic and magneto-optical storage media

FIELD: organic semiconductors.

SUBSTANCE: embossing or laminating film has at least one circuit component manufactured by using organic semiconductor technology, for instance one or more organic field-effect transistors; circuit component has several layers including electric functional layers with at least one organic semiconductor layer, at least one insulating layer, and electricity conductive layers. One or more layers of circuit component are made by way of thermal or ultraviolet replication including spatial structuring, part of at least one electric functional layer in spatial structuring region being fully separated.

EFFECT: improved circuit component production process using organic semiconductor technology.

28 cl, 9 dwg

FIELD: physics; semiconductors.

SUBSTANCE: invention relates to film with at least one electrical structural member and to method of manufacturing thereof. The method implies application of laser-cured adhesive compound onto a substrate film according to a specific pattern and/or irradiation according to a specific pattern so as to crystallise the adhesive according to a specific pattern. Onto adhesive, a decal film, which consists of substrate and electrical structural member, is applied. Substrate film is separated from the film body, which consists of base film, adhesive layer and electrical functional layer, so that in the first patterned area the electrical functional layer stays on the base film, and in the second patterned area the electric functional layer stays on the substrate and is separated from the base film together with the substrate.

EFFECT: enhanced method for manufacturing structural members using organic semiconductor technology.

30 cl, 5 dwg

Pattern generation // 2518084

FIELD: process engineering.

SUBSTANCE: invention relates to generation of electron or photon pattern on substrate, application of fluoropolymer to this end, to method of pattern generation and to electron or photon device thus made. Proposed method comprises: formation of film of said electron or photon material on said substrate and application of said fluoropolymer for protection of said electron or photon material in pattern generation.

EFFECT: ease of integration of proposed process with all common TFT architectures.

44 cl, 18 dwg

FIELD: power industry.

SUBSTANCE: invention relates to the photo-electric element consisting of electron-donating and electron-seeking layers, as a part of an electron-seeking layer containing methane fullerene where methane fullerene compounds with the generalised formula , where R = - COOCH3, - Cl, and the electron-donating layer is hydrochloric acid doped polyaniline or methane-sulphonic acid based polyaniline.

EFFECT: increase of overall performance of converters of solar energy into electric and idle voltage.

1 tbl, 4 ex

FIELD: electronics.

SUBSTANCE: invention relates to organic electronics, specifically to memory devices based on organic field effect transistors fabricated using photochromic compounds as part of active layer disposed at boundary between layer of semiconductor material and insulator. Invention provides formation and use of photo-switchable and electrically switchable organic field effect transistors, having in their structure a layer of photochromic molecules located on boundary between layer of semiconductor material and an insulator.

EFFECT: technical results achieved in implementation of claimed invention are a simple structure and technology of manufacturing photo-switchable and electrically switchable field effect transistors; possibility of creating multiple discrete states with different threshold voltages; achieving significant differences in currents IDS for different states (up to 10,000 times); providing spectral sensitivity of device: impact of light pulses of different wavelengths converts transistor in different states; enabling use of photo-switchable and electrically switchable FET as multibit memory cell; enabling optical and electrical programming of said memory cells; higher information recording density by implementing multibit mode.

4 cl, 10 dwg

Up!