Graphene-based tunnel field effect transistor
SUBSTANCE: in a tunnel field effect transistor with an insulated gate containing electrodes of source and drain made of multilayer graphene and located at an insulating substrate in the same plane, and also the gate made of a conducting material and located above the areas of source, tunnel junction and drain, electrodes of source and drain are oriented towards each other crystallographically by an even edge of a zigzag type and separated by a vacuum barrier transparent for charge carriers.
EFFECT: invention expands the inventory of tunnel transistor nanodevices; this device alongside its pronounced switching property has on the current-voltage curve of the source and drain electrodes the area with a negative differential resistance, which allows its functioning as the Gunn diode; the device requires lower voltage at the gate.
The invention relates to the field of nanoelectronics, and in particular, to the active elements based on carbon nanostructures, namely, to the transistors that implement the effect of electric current, and can be used as a basic switching device and the device with a negative differential resistance in the manufacture of digital integrated circuits.
Analogue of the invention is a tunneling field effect transistor with insulated gate proposed in . It consists of a tunnel field-effect transistor, the role of the source and drain which is highly doped silicon, and the gate is located over the area of the tunnel junction. The disadvantage of this device is the limitation of the operation speed due to the relatively small quantities of graphene mobility of charge carriers in silicon.
As a prototype, the device proposed in  and , in which the role of the electrodes plays a graphene with a mobility of charge carriers is much greater than that of silicon. A distinctive feature of this device is that the tunneling barrier in graphene by intercalation required region with compounds of boron, carbon and nitrogen having a hexagonal lattice (h-BCN) with different concentrations of these elements. As a result of the intercalation domain is formed �of heterostructure, have semiconducting conductivity type with a band gap of from 1 to 5 electron volts (depending on the concentration of elements in the compound (h-BCN). This device does not assume a particular orientation of the crystallographic lattice of the graphene relative to the tunneling gap. The main disadvantages of this device are the current problems in manufacturing technology domains heterostructures required sizes and shapes, as well as a relatively large voltage across the gate required for switching of the transistor.
The tunneling transistor with graphene electrodes is also proposed in . It has similarities with the prototype proposed in , , however, the area of the tunneling barrier is proposed here to form by putting in the tunneling gap of a silicon insert. The main disadvantage of this device is that at the moment, the technological implementation of this operation is clearly not feasible. Also, this transistor requires a relatively large voltage on the gate for his shift.
Thus, the objectives of the proposed transistor, the following. First, it expands the Arsenal tunnel transistor nanodevices. Secondly, along with switching ability, its volt-ampere characteristics�of cteristic have a region with negative differential resistance, and for this reason this device can perform functions such as transistor and diode Gunn. Thirdly, it requires a gate voltage that is lower than the existing counterparts. Fourthly, the technology of manufacturing nanoscale with crystallographically smooth edges is now more attainable than the technology to create domains of h-BCN desired shape and the technology of dielectric inserts made of silicon oxide.
In the inventive tunnel field effect transistor electrodes of the source and drain are made of sheets monosloevogo graphene lying on an insulating substrate in the same plane, oriented to each other crystallographically smooth edge type zigzag and split tunneling is transparent to the charge carriers by a vacuum barrier. The shutter is made of a conductive material, is located above the regions of the source, the tunneling transition and flow.
The distinctive features of this invention are:
1. The presence of the vacuum tunnel-transparent barrier (nanoscale the necessary width). Vacuum tunneling barrier does not require manipulation of the introduction of dielectric spacers or create a hybrid domain of the correct form, and can be carried out with the following process methods:
a) nanolithography using scanning tunneling microscopy;
b) local anodic oxidation;
d) nanofabrication using transmission electron microscopy;
e) catalytic nanoesca.
2. The orientation of graphene electrodes crystallographically smooth edge type zigzag to each other. Within this region are concentrated specific electronic boundary condition, the presence of which is necessary for the functioning of the device.
The combination of these features allows to achieve the task.
List of figures.
Fig.1 shows an external view of the device.
1. - graphene sheet, width is not less than 10 nm and a length of not less than 100 nm
2. - graphene sheet, width is not less than 10 nm and a length of not less than 100 nm
3. - insulator (e.g., silicon oxide)
4. - the shutter is made of a conductive material (e.g. gold)
5. - ohmic contacts (for example titanium), are intended to ensure the connection of the electrodes to an external electric circuit
6. - contact the source
7. - contact runoff
Fig.2 shows a schematic diagram of the density of States for the left and right electrodes.
In order to avoid effects of dimensional quantization, the graphene sheets 1 and 2 in Fig.1 must have a length (size in the direction from the source to the drain) not less than 100 nanometers and a width of not less than 10 nm. The thickness of the insulator 3 in Fig.1 should be enough�, to avoid tunneling current between sheets 1 and 2 in Fig.1 and gate 4 in Fig.1 (several times greater than the width of the tunneling gap). To external circuits sheets of graphene connected by means of an ohmic contact 5 in Fig.1. The device operation can be explained using Fig.2.
This figure depicts the marginal density of States for the left and right contacts, depending on the energy. Region States filled with electrons, painted black. The upper part of the black area corresponds to the Fermi level. Partially transparent rectangle denotes the transport window is the energy range in which the possible directional tunneling transport. Fig.2(a) corresponds to the condition in which the potential difference V between the source (6 in Fig.1) and the outlet (7 in Fig.1) equal to zero and the voltage Vggate (4 in Fig.1) no, the area is filled with boundary conditions of the left electrode corresponds to a region filled with boundary conditions of the right electrode, electron tunneling is possible, the current through the structure is not flowing. After the source and the drain is applied a potential difference, a portion of the filled States in the left electrode will correspond to the field-free States in the right electrode, there will be directional tunneling current of electrons from the left electrode to the right. On f�G. 2(b) depicts the band diagram when the potential difference between the source and drain, at which maximum value of the tunneling current, as in this case, a maximum of occupied States in the left electrode corresponds to the maximum of available States in the right electrode. In this state the transistor is "open". Further increase in potential difference will lead to a divergence of peaks of the density of States and the current drop, as shown in Fig.2(c). This site will be characterized by a negative differential resistance.
When applied to the gate electrode (4 in Fig.1) positive potential relative to the source and drain, will increase the area occupied States (the so-called condenser effect ), as illustrated in Fig.2(d). When applying a potential difference of the source-drain current in the transistor is suppressed due to the very low density of States in the transport window (Fig.2(e)). In this state the transistor is "closed". Further increase in the potential difference of the source-drain leads to the fact that one of the peaks of the density of States will be taken in the transport window (as shown in Fig.2(f)), the latter, in turn, will lead to a sharp increase (step) current between the source and drain.
Thus, this device can be carried out the process of switching from "open" to "closed" state by changing the potential of the gate which is the main floor�tively effect the operation of the transistor. In addition, this device has additional beneficial effects, namely the current-voltage characteristic of this device is present in the region with a negative differential resistance, which allows it to function as a Gunn diode.
 Patent RU 2354002
 G. Fiori, A. Betti, S. Bruzzone, and G. Iannaccone, Nano Vol.6, 2642 (2012)
 the Patent WO 2013080237 A1
 D. A. Svintsov, B. B. Finch, V. F. Lukichev, A. A. Orlikovskiy, A. Burenkov, P., Ochsner, Physics, 2013, volume 47, issue.2 p. 244
Tunneling field-effect transistor based on graphene with insulated gate containing the electrodes of the source and drain made of monosloevogo graphene and lying on an insulating substrate in the same plane, and the closure is made of a conductive material and positioned over the source areas, tunnel junction and the drain, wherein the source electrodes and drain are oriented to each other crystallographically smooth edge type zigzag and split tunneling is transparent to the charge carriers by a vacuum barrier.
SUBSTANCE: invention relates to thin metal-oxide films used to make a field-effect transistor. A coating liquid for forming a thin metal oxide film includes an inorganic indium compound, at least one of an inorganic magnesium compound and an inorganic zinc compound, glycolic ether and a diol, wherein the diol is selected from at least one of diethylene glycol, 1,2-propanediol and 1,3-butanediol.
EFFECT: invention enables to obtain a thin-film metal oxide coating with the required resistivity using a simple method, a large area, the required shape and with high accuracy.
12 cl, 10 dwg, 4 tbl
SUBSTANCE: semiconductor device comprises a thin-film transistor comprising a gate bus, the first insulating film, an oxide-semiconductor layer in the form of an island, the second insulating film, a source bus, a drain electrode and a passivating film, and also a contact site, comprising the first connection element, made of the same conducting film as the gate bus, the second connecting element made from the same conducting film as the source bus and the drain electrode, and the third connection element formed on the second connection element. The second connection element contacts with the first connection element in the first window provided in the first and second insulating films, the third connection element contacts with the second connection element in the second window provided in the passivating film, and the second connection element covers the end surfaces of the first insulating film and the second insulating film in the first window, but does not cover the end surface of the passivating film in the second window. As a result the conical shape of the contact hole of the contact site may be controlled with high accuracy.
EFFECT: reduced damage of a mask.
17 cl, 14 dwg
FIELD: electrical engineering.
SUBSTANCE: semiconductor device includes thin-film diode and protection circuit with protective diode. Thin-film diode includes semiconductor layer with the first, second zones and channel zone, gate electrode, the first electrode connected to the first zone and gate electrode and the second electrode connected to the second zone. When conductivity type of thin-film diode is n-type then anode electrode of the protective diode is connected to the line which is connected either to gate electrode or to the first electrode of thin-film diode. When conductivity type of thin-film diode is P-type then cathodic electrode of the protective diode is connected to the line which is connected either to gate electrode or to the first electrode of thin-film diode. Protective circuit does not include other diodes which are connected to the line so that current direction is opposite to the protective diode.
EFFECT: deterioration of thin-film diode properties can be decreased when size of the circuit is minimised.
12 cl, 37 dwg
SUBSTANCE: thin-film transistor comprises the first capacitor, comprising an area, in which the first electrode of the capacitor connected with an electrode of source, and the second electrode of the capacitor are arranged one on the other in direction of thickness at opposite sides of the first layer of a dielectric, formed between them, the second capacitor, comprising an area, in which the third and fourth electrodes of the capacitor are arranged one above the other in direction of thickness at the opposite sides of the second layer of the dielectric, formed between them, four output buses, stretching from the appropriate electrode of the capacitor in a plane direction, the first connection crossing the second and fourth output buses, when looking in direction of thickness, and the second connection crossing the first and third output buses, when looking in direction of thickness, besides, the second electrode of the capacitor and the gate electrode are connected to each other via the second output bus, the third electrode of the capacitor and the source electrode are not connected to each other, the fourth electrode of the capacitor and the gate electrode are not connected to each other.
EFFECT: invention makes it possible to create a thin-film transistor, occurrence of a defect in which may be prevented even in case of leakage in a capacitor connected to a transistor body.
37 cl, 13 dwg
SUBSTANCE: method of manufacturing of an enhancement/depletion (E/D) inverter having a number of thin-film transistors on the same substrate with channel layers consisting of an oxide semiconductor containing at least one element selected from In, Ga and Zn, involves the stages to form a first transistor and a second transistor; a channel layer thickness of the first and second transistors is mutually different; at least one of the channel layers of the first and second transistors are thermally treated.
EFFECT: expansion of the facilities allowing to manufacturer an inverter with oxide semiconductor thin-film transistors of various threshold voltages, simplified method of manufacturing of the inverter with such characteristics, cost reduction.
13 cl, 18 dwg
SUBSTANCE: in a memory element which comprises a substrate with deposited thin layers of ceric and silicon oxide and metal electrodes for recording and deleting information is made from glass which is pre-cleaned with acetone and isopropyl alcohol, on which a ceric oxide layer is deposited at temperature higher than 600°C and thickness of more than 3 nm and a silicon film with thickness of 50-100 nm.
EFFECT: invention prolongs information storage period, simplifies the manufacturing technology and reduces production expenses.
4 cl, 4 dwg
SUBSTANCE: amorphous oxide the composition of which changes in direction of the thickness of layer contains the compound the composition of crystal state of which is presented with formula In2-XM3XO3(Zn1-YM2YO)m , where M2 - element of group II with atomic number which is less than that of Zn (for example Mg or Ca), M3 - element of group III with atomic number which is less than that of In (for example B, Al, Ga or Y), x is within the range of 0 to 2, y is within the range of 0 to 1 and m is 0 or natural number which his less than 6, and at that, amorphous oxide has concentration of electron carriers of not less than 1012/cm3 and less than 1018/cm3 and has electron mobility which increases with increase of concentration of electron carriers.
EFFECT: amorphous oxide operates as semi-conductor to be used in active layer of transistor.
7 cl, 10 dwg
SUBSTANCE: in a field-effect transistor which includes an oxide film as a semiconductor layer, the oxide film has a channel part, a source part and a drain part, and concentration of one of hydrogen or deuterium in the source part and in the drain part exceeds that in the channel part.
EFFECT: invention enables to establish connection between the conducting channel of a transistor and each of sources and drain electrodes, thereby reducing change in parameters of the transistor.
9 cl, 13 dwg, 6 ex
SUBSTANCE: amorphous oxide compound having a composition which, when said compound is in crystalline state, has formula In2-xM3xO3(Zn1-YM2YO)m, where M2 is Mg or Ca, M3 is B, Al, Ga or Y, 0 ≤ X ≤ 2, 0 ≤ Y ≤ 1, and m equals 0 or is a positive integer less than 6, or a mixture of such compounds, where the said amorphous oxide compound also contains one type of element or several elements selected from a group consisting of Li, Na, Mn, Ni, Pd, Cu, Cd, C, N, P, Ti, Zr, V, Ru, Ge, Sn and F, and the said amorphous oxide compound has concentration of electronic carriers between 1015/cm3 and 1018/cm3.
EFFECT: amorphous oxide which functions as a semiconductor for use in the active layer of a thin-film transistor.
6 cl, 8 dwg
SUBSTANCE: in field transistor, comprising active layer and gate-insulating film, active layer comprises a layer of oxide, comprising In, Zn and Ga, amorphous area and crystalline area. At the same time crystalline area is separated from the first surface of interface, which is surface of interface between a layer of oxide and gate-insulating film, distance of 1/2 of active layer thickness or less, and it within the limits of 300 nm from surface of interface between active layer and gate-insulating film or is in point condition in contact with this surface of interface.
EFFECT: production of field transistor with high drift mobility.
4 cl, 4 dwg, 2 ex
FIELD: physics, photography.
SUBSTANCE: multiple-junction photoelectric device comprises first and second electrodes, a photoelectric stack in electrical contact with said first and second electrodes and having a plurality of photoelectric junctions, wherein each said photoelectric junction includes an electron-acceptor semiconductor layer and a light-absorbing semiconductor layer, having a substantially high work function than said electron-acceptor semiconductor layer, wherein said photoelectric junctions are divided by a recombination region which includes a transparent and current-conducting hole layer in ohmic contact with said light-absorbing semiconductor layer of said first photoelectric junction, and a transparent current-conducting electron-acceptor layer in ohmic contact with said electron-acceptor semiconductor layer of said second photoelectric junction; said recombination region forms a gradient work function of said transparent and current-conducting hole layer in ohmic contact with said light-absorbing semiconductor layer of said first photoelectric junction to said transparent and current-conducting electron-acceptor layer in ohmic contact with said electron-acceptor semiconductor layer of said second photoelectric junction, and having thickness in the range of one order of the sum of the Debye length of all layers of said recombination region.
EFFECT: invention improves the conversion efficiency of photoelectric cells by providing a low-energy path for recombination of electron and hole currents from pairs of photoelectric junctions.
33 cl, 10 dwg, 6 tbl
FIELD: medicine, pharmaceutics.
SUBSTANCE: group of inventions relates to medicine, namely to dermatology and mycology, and can be applied in the treatment of skin and its appendages. A pharmaceutical composition for external application contains nanoparticles for the laser thermotherapy of infectious affections of the skin and its appendages. The nanoparticles are characterised by, at least, one localised surface Plasmon resonance in the range of a wavelength from 400 to 1100 nm. The nanoparticles are dispersed in a physiologically acceptable carrier, which is characterised by the absence of the absorption or weak absorption and/or weak dispersion of light radiation in the said range of wavelengths and possessing biocidal properties. The pharmaceutical composition is applied on an affected area and irradiated by laser radiation with a wavelength close to the wavelength of the localised surface Plasmon resonance of the nanoparticles, contained in the composition, or equal to it. The irradiation is continued until the desirable temperature of heating of the said area is achieved.
EFFECT: group of inventions ensures an increased treatment efficiency, reduction of a risk of development of side effects, reduction of the number of recurrences due to the application of the pharmaceutical composition, capable of absorbing energy of the light radiation and transforming it into heat energy with the achievement of the specified temperature with laser irradiation at the specified wavelength with the lower intensity of laser radiation and possessing biocidal properties.
63 cl, 3 dwg, 1 tbl, 4 ex
SUBSTANCE: at a core (1) made of a steel wire layers of current-conducting wires of two types are wound - aluminium wire (2) and nanocomposite wire (3). The layers of wire (3) are alternated with the layers of wire (2). The layer of wire (3) is wound to the core (1). The wire (3) is formed of a wire stock (wire rod) produced of a nanocomposite material based on aluminium with a nanoparticle filler made as multilayer carbon nanotubes and reinforced in the process of multiple cold drawing of the wire stock up to the preset diameter.
EFFECT: increased capacity, mechanical strength and resistivity to sagging without an increase in its weight.
2 cl, 1 dwg
SUBSTANCE: invention relates to a microbubble generator and to a device for microbubble generation. One of the aspects of the claimed invention is represented by the microbubble generator, containing a vortex chamber, an opening for the supply of a fluid medium, connected to the vortex chamber, with the opening for the fluid medium supply being intended for the supply of the fluid medium along the line, which is tangent to the internal surface of the vortex chamber, and an output pipe, intended for directing the fluid medium in the direction, in fact, perpendicular to the direction of the fluid medium introduction. The output pipe passes through the surface of the vortex chamber wall and projects into the internal space of the vortex chamber. In accordance with the said configuration, it is possible to reduce the loss of kinetic energy of the vortex flow of the fluid medium by the isolation of the introduced fluid medium trajectory.
EFFECT: invention provides obtaining the microbubble generator, in which the size of the formed microbubbles can be reduced, that provides effective formation of the bubbles with a nanometric range size.
5 cl, 5 dwg
SUBSTANCE: light-emitting diode (LED) comprises a base, a light-emitting structure, a first electrode and a second electrode. An U-shaped electroconductive suspension for the light-emitting structure, which is transparent for the emitted light, is made on the base. The suspension lies on the base with one arm and is rigidly connected to the base. There is a series of elements rigidly connected to the arms between the arms in the direction from the base. The elements comprise an insulating layer, a first electrode, a layer which acts a mirror and a heatsink and a light-emitting structure. The LED is made as follows. A multilayer film element is formed on the base. The materials used are such that the layer geometry and intrinsic mechanical stress thereof enable to obtain a light-emitting structure and U-shaped suspension which is electroconductive and transparent for the emitted light. The step of forming the film element includes successively making a set of layers with intrinsic mechanical stress and a set of layers of the light-emitting structure. For the latter, two areas are formed, which are arranged with a gap with a depth to the last set of layers with intrinsic mechanical stress. Areas of the film element are obtained - an area which corresponds to the arm lying on the base, an area which corresponds to the arm connected to the light-emitting structure and an area corresponding to a loop. An insulating layer, on which the first electrode is made, is formed on the area of the film element which corresponds to the arm lying on the base. A layer which acts the mirror and heatsink is formed on the area of the film element which corresponds to the arm connected to the light-emitting structure. The film element is then partially separated from the base, leaving it connected on the area which corresponds to the arm lying on the base. The set of layers with intrinsic mechanical stress is transformed under the action of the intrinsic mechanical stress into U-shaped suspension with a loop and the obtained light-emitting structure between the arms. During separation, the set of layers of the light-emitting structure with the layer which acts as a mirror and a heatsink is turned over and the latter is brought into contact with the first electrode to form a rigid connection.
EFFECT: high efficiency of converting electrical energy into light energy and heat removal, reducing the dimensions of LEDs and integration with other optoelectronic devices on a single base.
21 cl, 6 dwg
SUBSTANCE: invention relates to powder metallurgy, in particular to powder production for application of wear- and corrosion-resistant coatings with high adhesive and cohesive strength by method of cold gas-dynamic spattering. The composite nanostructured powder for coatings application by the method of cold gas-dynamic spattering comprises particles containing metal core out of Hadfield steel, clad layer with thickness 4-8 mcm out of aluminium powder, diffusion layer out of intermetallic compounds with thickness 0.6-1.2 mcm created at border of the core and clad layer during annealing, and reinforced surface layer created during interaction of the clad layer and oxide reinforcing agent comprising nanoparticles 10-100 nm, at that the volume share of the oxide reinforcing agent in the clad layer is 30-40%.
EFFECT: coatings made from the suggested composite nanostructured powder have high adhesive and cohesive strength, uniform hardness distribution through the coating cross-section.
SUBSTANCE: invention relates to the field of selective catalytic reduction of nitrogen oxides, namely to a material of a carrier for the catalyst, used in the said process. The claimed carrier material represents particles of anatase titanium dioxide, including ≥85% by dry weight of TiO2 and ≤10% by dry weight of SiO2, with (i) SiO2 being mainly in the form, selected from the group, consisting of forms with the low molecular weight, nanoparticles and their combinations; and (ii) at least 50% of silicon atoms being in states Q3, Q2, Q1 and Q0 of the coordination environment. The invention also relates to a catalytic device for the neutralisation of Diesel exhaust, including such particles, a system for Diesel exhaust regulation, including the said catalytic device, a method in which the conversion of nitrogen oxides is catalysed in the presence of the claimed particles of anatase titanium dioxide, as well as to methods of obtaining the said particles.
EFFECT: claimed particles make it possible to increase the thermal stability of the final catalyst with the preservation or increase of the catalytic activity for the selective catalytic reduction of nitrogen oxides from mobile devices, operating on lean mixtures.
44 cl, 18 dwg, 15 tbl, 18 ex
SUBSTANCE: electrode coating contains the following components, wt %: ferrochrome - 58.0-60.0, ferroboron - 14.0-16.0, marble - 5.0-7.0, ferrosilicon - 3.5-4.5, fluorspar - 3.5-4.5, ferromanganese - 1.5-3.5, graphite - 5.5-6.5, potash - 0.5-1.5 and nanopowder of titanium carbonitride - 1.5-3.0. The electrode coating can be applied to metal rods from steel grade Sv-08A.
EFFECT: composition of the coating allows obtaining electrode paste with high plasticity, and electrodes with such coating provide for obtainment of deposited metal with hardness of up to 66 HRC, increased wear resistance and continued operating stability of reworked parts.
4 dwg, 1 tbl
FIELD: physics, robotics.
SUBSTANCE: invention relates to military robotics and can be used for proportional increase in force of combatant and at cargo handling. This exoskeleton comprises carcass system, drives, electronic control system and power supply battery. Said carcass system consists of black-reinforced plastic panel following the trunk rear shape and articulated leverage of reinforced-black tubes. Note here that carcass leverage drives are made of solid aerogel composed of carbon nanotubes with admixture of rubber shaped to 40-120 mm diameter cylinders with conical sharpening on ends. Said drives are attached to the levers by clamping of conical ends with the help of synthetic fabric bands impregnated with epoxy resin and tied by steel rivets.
EFFECT: electric power saving, increase in force and self-contained operation time, maximised combat efficiency.
SUBSTANCE: uniform, continuous and dense layer of pyrolytic carbon has width of carbon coating, close to monolayer coating, equal 0.4-0.5 nm, density of precipitated carbon coating, equal ρC = 2.0-2.1 g/cm3, specific surface SBET = 90-200 m2/g, cumulative volume of pores ΣVpore≤0.4 cm3/g, average size of pores DBET≤10 nm, most probable size of pores DBJH = 5-7 nm with absence of micro pores. Invention also relates to method of production of such mesoporous composite material.
EFFECT: claimed mesoporous composite material has high-quality thin carbon coating, which totally and uniformly covers external surface and walls of pores of said material.
4 cl, 3 dwg, 3 tbl, 10 ex
FIELD: magnetic materials whose axial symmetry is used for imparting magnetic properties to materials.
SUBSTANCE: memory element has nanomagnetic materials whose axial symmetry is chosen to obtain high residual magnetic induction and respective coercive force. This enlarges body of information stored on information media.
EFFECT: enhanced speed of nonvolatile memory integrated circuits for computers of low power requirement.
4 cl, 8 dwg