Semiconductor structure for photo converting and light emitting devices

FIELD: physics.

SUBSTANCE: semiconductor structure for photo converting and light emitting devices consists of semiconductor substrate (1) with face surface misaligned from plane (100) through (0.5-10) degrees and at least one p-n junction (2) including at least one active semiconductor ply (3) arranged between two barrier plies (4) with inhibited zone width Eg0. Active semiconductor ply (3) consists of 1st and 2nd type spatial areas (5, 6) abutting of barrier plies (3) and alternating in the plane of active semiconductor ply (3). 1st type spatial areas (5) feature inhibited zone width Eg1 < Eg0, while 2nd type areas have inhibited zone width Eg2 < Eg1.

EFFECT: higher efficiency owing to increased photo flux and higher level of photo generation and charge carrier separation, higher probability of photon generation and lower probability of radiation-free recombination.

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The invention relates to semiconductor electronics and can be used to create solar cells (solar cells) and light-emitting devices (LEDs, laser diodes, etc.).

In recent decades, the world has steadily increased the interest in renewable energy, in particular to the possibility of using solar energy. For space vehicles, photovoltaics (solar energy) is the only source of energy that is largely responsible for its development, however, in recent years is constantly increasing and the share of photovoltaics in the total energy generated by ground-based power plants. With this development of semiconductor structures cascaded photovoltaic cells (solar cells) on the basis of the compounds (A3B5that converts concentrated radiation is one of the most promising ways to achieve high efficiency of photoelectric conversion. Semiconductor structures on the basis of the compounds (A3B5also actively used to create light emitting devices in the first place, LEDs and laser diodes of both visible and infrared range. The processes of photopleasure (generation and separation of charge carriers by absorption of photons of light) and light emission (generation �otons due to the radiative recombination of injected into the structure of charge carriers in semiconductor structures are essentially different directions of the same process - absorption/emission of photons. This leads to the use of new semiconductor structures for improvement of utilitarian features such as solar cells and light-emitting devices.

A significant limitation on the efficiency cascade solar cells, as well as on the efficiency and the wavelength of the light-emitting devices impose properties of semiconductor materials of the semiconductor elements of the structure. Primarily, it refers to the lattice parameter. The presence of misalignment of materials on the lattice parameter leads to the accumulation of elastic stresses, which will be to relax when it reaches a certain thickness, with the formation of defects, which is especially critical for photoperiodic structures due to the large thickness of the photoactive layers. The need to match the materials on the lattice parameter limits the absorption edge or the energy of the luminescence of the bulk materials, as for solid solutions the change of the absorption edge, which is possible only when you change the composition, as a rule, leads to the change of the lattice parameter of the material.

Thus, enabling the extension of the spectral range of photosensitivity of the cascade solar cells, which entails an increase in the generated payroll�current, and a change in wavelength, while maintaining the high efficiency light-emitting devices is an important task to realize the potential efficiency cascade solar cells and the production of high-efficiency light-emitting devices.

One way of changing the absorption edge of semiconductor materials that provide as the extension of the photosensitivity of the FEP, and a wider range of possible wavelengths of light-emitting structures is the use of quantum-well heterostructures with quantum wells (QWS) or quantum dots (CT). Both of these approaches allow you to change the absorption edge of bulk material, however, have some limitations.

The use of QWS in vodoprivreda or light-emitting structures allows to obtain a high level of quantum efficiency due to the fact that QW absorbs/radiates throughout the surface, however, the long wavelength absorption edge shift/radiation (relative to barrier layer) remains small. When using CT grown by the Stransky-Krastanov there is a major shift of the absorption edge, however, it is impossible to obtain a high level of quantum efficiency due to low surface density of these QDs.

Known semiconductor structure for photodreamstudio and�atoslucas devices (see application US 2011127490, IPC H01L 21/00, published 2.06.2011) containing a semiconductor substrate on which is grown a semiconductor structure comprising nanowires with quantum dots containing three layers of vertically coupled quantum dots big size, entered into between barrier layers with a band gap of Eg0while inside quantum dots arise bordering both the barrier layer region with Eg1<Eg0inside which are not contiguous with the barrier layers of the quantum dots of small size with Eg2<Eg1.

A disadvantage of the known semiconductor structure is low density CT of small size, as reflected in the low absorption/emission of photons, and low relative to the planar layers of the surface density of nanowires, which also reduces the efficiency of absorption/emission of photons. In addition, a large confining potential in CT small size results in a low probability of release and separation of photogenerated carriers.

Known semiconductor structure for photodreamstudio of the device (see application US 2011073173, IPC H01L 21/02, H01L 31/0248, publ. 31.03.2011) including rear and front electrodes, a semiconductor layer with a band gap of Ego doped with impurity atoms and includes nanoers�Ernie region with E g1<Eg0caused by doping of a semiconductor with impurity atoms of the second, thus, depending on the spatial distribution of impurity atoms of the second, nanoscale region can implement the localization of carriers in one direction (quantum well), in two directions (quantum wire) or three directions (quantum dot).

A disadvantage of the known semiconductor structure for photodreamstudio device is the inability to extend the spectral sensitivity in the long wavelength region of more than 120 MeV, since the carriers localized in nanoscale regions, otherwise you will not be able to be thermally ejected from them. In addition, the field Eg1will localize only the minority charge carriers, while the main media will not be localized, thus reducing the probability of absorption/radiation.

Known semiconductor structure for photodreamstudio device (see patent application US 2012285537, IPC B82Y 20/00, H01L 31/00, publ. 15.11.2012) containing conductor layer of the p-type conductivity, a conductor layer of n-type conductivity, between which is a layer of semiconductor with a superlattice. Barrier layers with a band gap of Eg0include vertically and horizontally linked layers of quantum dots, which are formed minizone � E g1<Eg0while the confinement potential for the charge carriers in minisonic not exceed more than two times thermal energy kt (K is Boltzmann constant, j/K; T is the absolute temperature, K, at room temperature.

A disadvantage of the known semiconductor structure is a low CT density, as reflected in the low absorption/emission of photons.

Known semiconductor structure for light emitting devices (see N. N. Ledentsov, D. Bimberg, Yu. M. Shernyakov, V. Kochnev, M. V. Maximov, A. V. Sakharov, I. L. Krestnikov, A. Yu Egorov, A. E. Zhukov, Appl. Phys. Lett. 70 (21), 26 May 1997, p. 2888) comprising a substrate made of GaAs, and structure-based active layer made of InGaAs with an indium content of less than 40 atomic (at) % with quasiperiodic modulation of the composition and thickness in the plane of the layer, and provides the areas with lower indium content with a band gap of Eg1and areas with a high content of India with a band gap of Eg2<Eg1,

A disadvantage of the known semiconductor structure for light emitting devices is the low density regions with a high content of India, as the modulation of the composition occur randomly and do not have a periodic structure, which explains the relatively low intensity of radiation.

The closest to this technical solution, in the aggregate�upnote essential features is a semiconductor structure for photodreamstudio the device which can also be used for a light emitting device (see JP 2011222620, IPC H01L 31/00, H01L 31/04, publ. 04.11.2011), adopted as a prototype and comprising a semiconductor substrate, the active semiconductor layer of one conductivity type made of GalnP and having in a direction parallel to the substrate plane, the spatial domain of two types: the area of the first type with a lower indium content with a band gap of Eg1and the area of the second type with a high content of India with a band gap of Eg2<Eg1and the active semiconductor layer of another conductivity type made of GaInP and having in a direction parallel to the substrate plane, the spatial domain of two types: the area of the first type with a lower indium content with a band gap of Eg1and the area of the second type with a high content of India with a band gap of Eg2<Eg1. In the direction perpendicular to the substrate plane, the thickness of areas of both types for both layers equal to the thickness of the respective layers.

In a semiconductor structure - prototype an important role plays the fact that the field Eg2have a smaller size than the distance between the dislocations in the layers, and localization of charge carriers in them in the transverse direction to the structure snecial�but reduces bestlocation recombination in layers with a high density of dislocations. In this region with Eg2formed through vertical storage CT InP with narashivaniem very thin layer of GalnP such that CT from the nearby layers are in direct contact with each other, forming a column of CT, the thickness of which is equal to the total thickness of the layer.

A disadvantage of the known semiconductor structure is the localization of charge carriers in regions of the second type only two, not in three directions and an increased likelihood of surface bestlocation recombination. In addition, the low density CT InP causes small absorption/emission of a photon. When used in photoprobes device structure-prototype does not provide the absorption edge shift is more than 120 MeV.

The object of the present solution is the creation of such a semiconductor structure for photodreamstudio and light-emitting devices, which would increase the efficiency of solar cells and light emitting devices. When applying patterns in photoperiodic devices increase in efficiency is due to the increase of the photocurrent in the propagation of the spectral sensitivity in the long wavelength region, and ensure a high level of generation and separation of charge carriers. When applying patterns in light-emitting devices increase efficiency� occurs due to the increase in the probability of generation of photons and reduce the recombination through high-density areas the confinement of charge carriers in three directions.

The task is achieved in that the semiconductor structure for photodreamstudio and light-emitting device includes a semiconductor substrate with a front surface (100), disoriented from the plane (100) by up to 10 degrees, and at least one p-n junction comprising at least one active semiconductor layer, enclosed between two barrier layers with a band gap of Eg0consisting of bordering barrier layers and alternating in the plane of the active semiconductor layer spatial regions of the first and second types, wherein the spatial region of the first type have a width of the forbidden zone (Eg1<Eg0and the spatial region of the second type have a width of the forbidden zone (Eg2<Eg1.

New in a semiconductor structure is the performance of the semiconductor substrate with a front surface disoriented from the plane (100) 0.5 to 10 degrees, and the inclusion in the composition of barrier layers between which is the active semiconductor layer. The misorientation of the front surface of a semiconductor substrate, the formation on its surface atomic steps, along the lines which are created in the area of the active semiconductor layer� high-density, arrays of spatial regions of the second type, which provides three-dimensional localization of charge carriers due to the inclusion in the composition of the semiconductor structure of barrier layers between which is the active semiconductor layer.

When orientation of the front surface of a semiconductor substrate at an angle of less 0.5 degrees, the distance between atomic levels will be so large that the density of arrays of spatial regions of the second type will be commensurate with the known density of quantum dots.

When orientation of the front surface of a semiconductor substrate at an angle that is less than 10 degrees, the size of the spatial regions of the second type is less than 3 nm, resulting in localization of charge carriers will be very weak.

In a semiconductor structure band gap (Eg0, the band gap (Eg1and band gap (Eg2may satisfy the relations:

Eg0-Eg1≤130 MeV,

Eg1-Eg2≤130 MeV.

In the semiconductor structure area of the second type can be made in the form of indium-enriched regions that are limited in the transverse direction (i.e. in the direction perpendicular to the semiconductor substrate) barrier layers, and in the longitudinal direction of restricted depleted indium regi�s of the first type.

The semiconductor structure of semiconductor solid solution, advising average composition of the active layer, may be out-of-sync with the barrier layers on the lattice parameter of not more than 4%.

In the semiconductor structure, the barrier layers and the active semiconductor layer can be formed from a solid solution AlGaInAs.

Thus in a semiconductor structure, the barrier layers may be made of GaAs or solid solution GaInAs with indium content of not more than 2 at.%, and the active semiconductor layer may be made of InxGa1-xAs with the average content of x India (20-50) at.%.

Thus, the semiconductor structure region of the second type can be made in the form of indium-enriched regions with a size in a plane parallel to the substrate plane, 5-40 nm and the average composition I>x bounded in the transverse direction of the barrier layers, and in the longitudinal direction is restricted depleted indium regions of the first type with an average composition z<x, with the area of the second type have a surface density of 5·1011cm-2.

In the semiconductor structure, the barrier layers and the active semiconductor layer can be formed from a solid solution AlGaInP.

Thus in a semiconductor structure, the barrier layers can be formed from a solid solution with GalnP containing�amount of force India (48-52) at.%, and the active semiconductor layer may be made of InxGa1-xP with an average grade x India (10-30) at.%.

The semiconductor structure may be formed as a phototransducer.

The semiconductor structure may be in the form of an led or laser diode.

This technical solution is illustrated by drawings, where:

Fig.1 shows a schematic representation of a cross section of the present semiconductor structure;

Fig.2 shows an image of transmission electron microscopy (TEM) high-resolution cross-sectional samples containing active semiconductor layers on the base layer InxGa1-xAs with the average composition of indium x=30 at.%;

Fig.3 shows the dark-field TEM image of the cross section of the samples containing the active semiconductor layers on the base layer InxGa1-xAs with the average composition of indium x=40 at.%;

Fig.4 shows bright-field TEM image of the cross section of the samples containing the active semiconductor layers on the base layer InxGa1-xAs with the average composition of indium x=50 at.%;

Fig.5 shows the dark-field TEM image of the cross section of the samples containing KG, obtained by a known method Stransky-Krastanov for the relaxation of a germinal layer InxG 1-xAs with the composition of indium x=60 at.%;

Fig.6 shows a darkfield image in the reflection g=(-2-20) sensitive to the elastic stresses on the cross section (1-10) semiconductor structure according to the present invention containing 10 active semiconductor layers formed by deposition of a layer of InGaAs with an average indium content x=40 at.%.

Fig.7 shows a comparison of photoluminescence spectra (curve 1) light-emitting semiconductor structure and the spectrum of the photocurrent (curve 2) vodoprivreda semiconductor structure of the present invention on the basis of 10 active semiconductor layer on the base layer InxGa1-xAs with the average composition of indium x=40 at.%;

Fig.8 shows the spectral characteristics of the external quantum efficiency vodoprivreda patterns without active layers of the present invention (curve 3) and vodoprivreda semiconductor structure of the present invention, comprising 20 active semiconductor layer on the base layer InxGa1-xAs with the average composition of indium x=40 at.% (curve 4);

Fig.9 shows the dependence of the increase of the photocurrent for a standard GaAs solar cells, when administered in its p-n junction 10 of the active semiconductor layers of the present invention on the basis of layers InxGa1-xAs with the average composition of India � from 20 at.% to 100 at.%;

Fig.10 shows a comparison of the dependences of the optical modal gain from the current density for the laser diode, comprising five layers of standard quantum dots obtained by a known method Stransky-Krastanov (curve 5) and the laser diode of the present invention, which includes five active semiconductor layer on the base layer InxGa1-xAs with the average composition of indium x=40 at.% (curve 6);

Fig.11 shows the comparison of the dependences of the threshold current density, shown in one layer for laser diodes, comprising five layers of quantum wells (curve 7), and laser diodes according to the present invention, which includes five active semiconductor layer on the base layer InxGa1-xAs with the average composition of indium x=40 at.% (curve 8), and is also dependent on the wavelength of the laser for generating laser diodes, comprising five layers of quantum wells (curve 9) and laser diodes according to the present invention, which includes five active semiconductor layer on the base layer InxGa1-xAs with the average composition of indium x=40 at.% (curve 10).

The present semiconductor structure for photodreamstudio and light-emitting devices shown in Fig.1. It consists of a semiconductor substrate 1, and at least one p-n junction 2 comprising at least one active semiconductor layer 3, �alchemy with relaxation along the lines of atomic steps on a semiconductor substrate, disoriented from the plane (100) 0.5 to 10 degrees, a layer made of, for example, of InxGa1-xAs with the average composition x India from 20 to 50 at.% or of InxGa1-xP with the average composition x India from 10 to 30 at.%, concluded between the barrier layer 4 with a band gap of Eg0made of GaInAs with the composition x India no more than 2 at.% or from solid solution GaInP composition x India 48-52 at.%, in this case the active semiconductor layer 3 includes bordering both the barrier layer 4 alternating in the plane of the active semiconductor layer 3 spatial region 5 of the first type and the spatial region 6 of the second type, arising from the directed migration of the atoms of In and Ga during the deposition of the layers, wherein the spatial region 5 of the first type, for example, of InzGa1-zAs or-InzGa1-zP with the average composition z<x, with the width of the forbidden zone (Eg1<Eg0a spatial region 6 of the second type, for example of InxGa1-xAs or-InxGa1-yP with mean composition I>x, with the width of the forbidden zone (Eg2<Eg1.

An important feature of the present semiconductor structure from the point of view of photopleasure is that it is provided not only by the absorption of photons with energies Eg1and Eg2but also rely on the condition�I for efficient separation of photogenerated charge carriers, when the difference between Eg1and Eg2and between Eg0and Eg1do not exceed 130 MeV. This is especially important in the absorption of the most long-wavelength photons of energy hω2when the separation of charge carriers occurs in two stages, first they go through thermal casting of spatial regions 6 of the second type in the spatial domain 5 of the first type, and then due to the heat of the cast in the barrier layers 4. Thus, the present semiconductor structure determines the shift of the spectral sensitivity of the solar cells in the long wavelength region of not less than 260 MeV.

An important factor contributing to the advantage of the present semiconductor structure from the point of view of application in light-emitting devices, an ultra-high-density spatial regions 6 of the second type with Eg2by streamlining their lines of atomic steps on unidirectional glass semiconductor substrate 1, which leads to increased emission of a photon of them while maintaining the advantages of localization of charge carriers in three dimensions.

The basis of the invention lies original method of forming on a semiconductor substrate, disoriented from the plane (100) 0.5 to 10 degrees, the active semiconductor layer 3, which is a hybrid quantum� holes and quantum dots, realized at certain modes of growth layers, mismatched in lattice parameter with barrier layers, and based on the directed migration of the atoms of In and Ga during the deposition of the layer InxGa1-xAs with the average composition x India 20-50 at.% or layer of InxGa1-xP with the average composition x India from 10 to 30 at.% on the surface of GaAs or agreed with him GaInP. The change in surface energy of the strained layers in the areas of atomic steps results in an ordering of regions with different indium content, which allows you to control their concentration by changing the angle of orientation of the substrate.

The use of relatively little mismatched solid solutions InxGa1-xAs or-InxGa1-xP with respect to the difference of lattice parameters the lattice parameter of the substrate (Δa/a) of less than 4% it is possible to grow a layer of a sufficiently large thickness, the voltage in which under certain conditions are transformed due to the formation of areas depleted and indium-rich indium. This mechanism of growth on surfaces with a high density of atomic steps leads to the formation of a dense array of indium-enriched areas within depleted indium quantum well. In the case of growth of quantum dots known method Stransky-Krastanov use InGaAs solid solution with a large out-of-sync�eat or mostly clean InAs (Δa/a ~7%). Large misalignment leads to relaxation of elastic stresses at small layer thicknesses, resulting in the formation of pyramidal Islands - quantum dots.

Given the fact that the lattice parameter of semiconductor compounds is in the range of 5 to 7 angstroms, the distance between atomic steps on the surface of substrates, disoriented from 0.5 to 10 degrees, will be from 60-80 nm 3-4 nm. Thus, when using atomic steps disoriented on semiconductor surfaces to modulate relaxation relatively thin strained layers InxGa1-xAs or-InxGa1-xP it is possible to provide the surface density of indium depleted layers from 1·1010cm-22-5·1012cm-2.

The present semiconductor structure in photoprobes device (Fig.1) works as follows. Photons with more energy hω1corresponding to the band gap (Eg1spatial regions 5 of the first type active semiconductor layer 3, give rise to charge carriers in the spatial area 5 of the first type, which are separated due to thermal emission in the barrier layers 4. Photons with more energy hω2corresponding to the band gap (Eg2spatial regions 6 of the active layer 3 of the second type, �wait for the media in the spatial area 6 of the second type, which are separated due to thermal emission of a first spatial region 5 of the first type, and then in barrier layers 4.

The present semiconductor structure in the light-emitting device (Fig.1) works as follows. The charge carriers injected from the barrier layer 4, captured in the spatial domain 5 of the first type, ensuring their localization in one direction (similar to the quantum well) can recombine, emitting a photon with energy hω1corresponding to the band gap (Eg1spatial regions 5 of the first type active semiconductor layer 3. The charge carriers captured in the spatial region 6 of the second type, ensuring their localization in three directions (similar to quantum dots)? can recombine, emitting a photon with energy hω2corresponding to the band gap (Eg2spatial regions 6 of the second type of the active semiconductor layer 3.

This semiconductor structure is illustrated by studies using the transmission electron microscopy (TEM). The TEM images of the cross-section structures with relaksiruyushaya layers InxGa1-xAs an average composition of 30% (Fig.2), 40% (Fig.3), 50% (Fig.4) and 60% (Fig.5) you can see that the active semiconductor layers in the case of x=30 at.%, 40 at.% and 50 at% are planar, however, there are roughnesses of the interfaces associated with the relaxation of elastic stresses. As for the composition x=60 at.% clearly there is a relaxation with the formation of islets of quantum dots (known method Stransky-Krastanov). Thus, as described above the active semiconductor layer occurs when the average composition of indium in the layer is less than 60%.

Fig.6 shows obtained using a transmission electron microscope darkfield image in the reflection that is sensitive to the elastic stresses, the cross-section of a semiconductor structure of the present invention containing 10 active semiconductor layers formed by deposition of a layer of InGaAs with an average grade x India 40 at.%. In the transverse direction of clearly show the presence of dipoles of dark and white spots, which indicate that occur alternating in the plane of the active semiconductor layer 3 spatial region of greater thickness and a high content of India (region 6 of the second type) and spatial areas of smaller thickness and a smaller structure in India (region 5 of the first type).

The size of the indium-rich regions is 15-20 nm, and their height is approximately equal to or slightly greater than the width of deposited layer 3-15 nm, that is in them is the localization of carriers in three directions, with distances between the�tion between them varies from 15 to 40 nm, it allows to estimate the average surface density of 6·1010to 5·1011cm-2that is 5-10 times higher than the density of a standard CT scan, obtained by a known method Stransky-Krastanov.

Example 1. Was manufactured semiconductor light-emitting structure, which includes grown on a semiconductor GaAs substrate with a front surface disoriented from the plane (100) 2 degrees, 10 active semiconductor layers on the basis of InxGa1-xAs with the average content of x India 40 at.%, prisoners between barrier layers of GaAs, and the light-emitting structure on the basis of 10 layers of InAs quantum dots obtained by a known method Stransky-Krastanov. In the spectrum of the fluorescence light-emitting semiconductor structure, comprising 10 of the active semiconductor layers, it is possible to see the presence of recombination using two levels: in the spatial area of the first and second type (Fig 7). The integral intensity of a photoluminescence light-emitting semiconductor structure through the active semiconductor layer 5 times greater than the intensity of the light emitting structure through layers of InAs quantum dots that shows a higher density regions of the second type into the active semiconductor layer in comparison with the density of quantum dots.

Example 2. Was manufactured semiconductor equipment�protein structure GaAs phototransducer on a semiconductor GaAs substrate with a front surface disoriented from the plane (100) of 10 degrees, the space charge region of the p-n junction which included 10 active semiconductor layer on the base layer InxGa1-xAs with the average composition of indium x=40 at.%. Such a semiconductor structure has demonstrated a level of the external quantum efficiency of about 20% in the absorption region of the spatial regions of the first type and about 15% in the absorption region of the spatial regions of the second type (Fig.7).

Example 3. Was manufactured semiconductor structure phototransducer on a semiconductor GaAs substrate with a front surface disoriented from the plane (100) 6 degrees, the space charge region of the p-n junction which included 20 active semiconductor layer on the base layer InxGa1-xAs with the average composition of indium x=40 at.%. Such a semiconductor structure has demonstrated a level of the external quantum efficiency of about 35% in the absorption region of the spatial regions of the first type and about 30% in the spatial domain the absorption regions of the second type and to provide an increase of the photocurrent of the order of 3 mA/cm2in comparison with the standard GaAs by image Converter (Fig.8).

Example 4. Were created photovoltaics on a semiconductor GaAs substrate with a front surface disoriented from the plane (100) 6 g�of adosow, with 10 active layer through the active semiconductor layer InxGa1-xAs with the average composition of indium x from 20 to 50 at.%, and photovoltaics on a semiconductor substrate of GaAs with 10 layers of KG obtained by a known method Stransky-Krastanov, when the relaxation layer InxGa1-xAs with the average composition of indium x from 60 to 100 at.%. The maximum increase of the photocurrent due to the introduction of the active layer or layers of quantum dots was observed at a concentration of indium of from 20 to 50 at.% (Fig.9).

Example 5. Was synthesized laser epitaxial structure of the present invention on a semiconductor GaAs substrate with a front surface disoriented from the plane (100) 6 degrees, with an active semiconductor region that includes 5 active semiconductor layer on the base layer InxGa1-xAs with the average composition of indium x=40 at.%, the waveguide of GaAs with a thickness of 150 nm, a limited emitter layers of Al0,34Ga0,66As. Was also synthesized laser with the known epitaxial active region based on InAs quantum dots formed by a mechanism Stransky-Krastanov and covered with a layer of InOf 0.15GaOf 0.85As the thickness of 5 nm. In the GaAs waveguide with a thickness of 400 nm, limited by the emitter layers of AlOf 0.7GaThe 0.3As was re-precipitated 5 rows of such quantum dots. In addition? was sintezirovan�and the laser with the known epitaxial active region on the basis of a single quantum well In 0,2GaThe 0.8As placed in a GaAs waveguide with a thickness of 400 nm, a limited emitter layers of Al0.34Ga0.66As. The structures were fabricated laser diodes of the strip structures of different lengths and with chipped edges with a strip width of 100 μm. The wavelength of the generation was in the range of 1.11-1,09 μm for lasers with an active region, formed in accordance with the present invention, 1.85 to 1.265 μm in the structure with quantum dots InAs/lnGaAs, of 0.99-0.98 μm in the structure with quantum pit InGaAs. From experimental watt-voltage characteristics measured for laser diodes of different lengths, was determined the dependence of the optical honey gain from the pump current density, and the dependence of the threshold current density from optical losses. A comparison was made of optical modal gain in laser structures with an active area formed in accordance with the present invention, and quantum dots InAs/InGaAs (Fig.10). The highest value of the modal gain in the active region, formed in accordance with the present invention, was 54 cm-1while in the structure with quantum dots InAs/InGaAs - was 23 cm-1(2.34 fold less). A laser structure with an active region, formed in accordance with the present invention, has a narrow waveguide layer and emitter�mi layers with a relatively low aluminum content. According to calculations, this leads to a reduction in 1,334 times factor optical limitations in comparison with known laser structure with quantum dots InAs/InGaAs. Taking into account differences in the values of modal gain factor and optical constraints, material gain of the active region, formed in accordance with the present invention, 3,12 times strengthening the known material of the active region on the basis of quantum dots InAs/InGaAs formed on the mechanism Stransky-Krastanov. A comparison was made of the threshold current density and the wavelength of the laser generating laser with an active region, formed in accordance with the present invention, and known laser with quantum pit InGaAs (Fig.11). Attributed to one layer of the active region, the lowest value of the threshold current density was 46 A/cm2in the structure with an active region, formed in accordance with the present invention, and 110 A/cm2in the structure with quantum pit InGaAs. In this case, the wavelength of laser oscillation in the structure with an active region, formed in accordance with the present invention, more than exceeded 100 nm wavelength laser generation in the known laser-based quantum well InGaAs.

1. Semiconductor structure for photodreamstudio and light-emitting devices, comprising polypr�vodnikova substrate with a front surface disoriented from the plane (100) 0.5 to 10 degrees, and at least one p-n junction comprising at least one active semiconductor layer, enclosed between two barrier layers with a band gap of Eg0consisting of bordering barrier layers and alternating in the plane of the active semiconductor layer spatial regions of the first and second types, wherein the spatial region of the first type have a width of the forbidden zone (Eg1<Eg0and the spatial region of the second type have a width of the forbidden zone (Eg2<Eg1.

2. Semiconductor structure according to claim 1, characterized in that the band gap (Eg0, the band gap (Eg1and band gap (Eg2satisfy the relations:
Eg0-Eg1≤130 MeV,
Eg1-Eg2≤130 MeV.

3. Semiconductor structure according to claim 1, characterized in that the region of the second type made in the form of indium-enriched regions that are limited in the transverse direction of the barrier layers, and in the longitudinal direction is restricted depleted indium areas of the first type.

4. Semiconductor structure according to claim 1, characterized in that the semiconductor solid solution, corresponding to an average composition of the active layer, out-of-sync with the barrier layers on parametrised not more than 4%.

5. Semiconductor structure according to claim 1, characterized in that the barrier layers and the active semiconductor layer is made of a solid solution AlGaInAs.

6. Semiconductor structure according to claim 5, characterized in that the barrier layers are made of GaAs or solid solution GaInAs with indium content of not more than 2 at.%, and the active semiconductor layer is made of InxGa1-xAs with the average content of x India 20-50 at.%.

7. Semiconductor structure according to claim 6, characterized in that the region of the second type made in the form of indium-enriched regions with a size in a plane parallel to the substrate plane, 5-40 nm and the average composition of y>x bounded in the transverse direction of the barrier layers, and in the longitudinal direction is restricted depleted indium regions of the first type with an average composition z<x, with the area of the second type have a surface density of 5·1011cm-2.

8. The semiconductor structure of claim 1, characterized in that the barrier layers and the active semiconductor layer is made of a solid solution AlGaInP.

9. Semiconductor structure according to claim 8, characterized in that the barrier layers are made of a solid solution GaInP with indium content 48-52 at.%, and the active semiconductor layer is made of InxGa1-xP with an average grade x India (10-30) at.%.

10. Semiconductor struc�and according to claim 5 or claim 8, characterized in that is made in the form of a phototransducer.

11. Semiconductor structure according to claim 5 or claim 8, characterized in that is made in the form of an led or laser diode.



 

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Laser-thyristor // 2557359

FIELD: physics, optics.

SUBSTANCE: invention can be used to generate a controlled sequence of high-power laser pulses. The laser-thyristor includes a cathode region (1), which includes an n-type substrate (2), a wide-band gap n-type layer (3), an anode region (4), which includes a p-type contact layer (5), a wide-band gap p-type layer (6), which is also the optical confinement layer of the laser heterostructure and the emitter, which injects holes into the active region (13), a first base region (7), a p-type layer (8), a second base region (9), an n-type layer (10), a waveguide region (12), Fabry-Perot optical resonator, formed naturally by a cleavage surface (14) coated with an antireflecting coating and naturally by a cleavage surface (15), a first ohmic contact (16), a second ohmic contact (18), a meso-channel (19), a third ohmic contact (20), wherein parameters of the materials of the layers of the first and second base regions satisfy certain expressions.

EFFECT: increasing peak output optical power and reducing the amplitude of the control signal.

4 cl, 4 dwg

FIELD: physics.

SUBSTANCE: radiation source is in the form of two thin (less than 0.5 mm) plates of heat-resistant glass glued around the periphery in a vacuum-tight manner, on which film electrodes are deposited, with a transparent electrode deposited on plate and a reflecting electrode on the other. A microchannel plate is tightly bonded to the plates in between said plates, the microchannel plate having a discontinuous layer of phosphor and electron emitter nanopowders on the semiconductor surface of its channels. Electron emission, amplification of the flux thereof and cathode luminescence (radiation) occur in the microchannel plate. The plate with the transparent electrode is bonded to a detachable transparent plate on the external side of the housing, said detachable transparent plate having inside it or on its surface nanopowder of a material with a spectral radiation conversion property. Microchannels of the microchannel plate, having length L and diameter w, are inclined at an angle φ to the field lines of the dc or ac voltage V applied between the film electrodes, such that voltage acting on portions of the channel, estimated using the formula V(w/L)tgφ, is established depending on the properties of the selected phosphors and the electron emitter.

EFFECT: wider spectral range, controlling spectral characteristics, high efficiency of electron-photon and electro-optical conversions.

4 dwg

Led lamp // 2556871

FIELD: electricity.

SUBSTANCE: invention relates to lighting engineering and can be used for manufacture of the light sources used as a part of lighting equipment for the general and local external and internal lighting. The LED lamp contains the convex lens, the board with light-emitting diodes installed from the end face side of the hollow radiator and the connector for connection to the power supply circuit placed in the radiator cavity. The technical result is achieved due to that the radiator cavity contains the thin-walled cylinder made of heat-conducting electric insulating material. Between the board and the named cylinder the metal orifice is installed with a possibility of heat exchange, meanwhile on the lower base of the thin-walled cylinder the connector for connecting to the power supply circuit is made.

EFFECT: decrease of axial dimensions of the lamp and improvement of conditions of heat exchange between the board of light-emitting diodes and environment.

3 cl, 2 dwg

Lighting device // 2555199

FIELD: lighting.

SUBSTANCE: invention relates to the lighting device containing a material (2) for the initial light (4) conversion to the secondary light (5), at that the material (2) for conversion contains the converting photoluminescence material (15), that degrades to non-conversion photoluminescence material within time when the material (2) for conversion is lighted by the initial light (4). Material (2) for conversion is adapted such that when the material (2) for conversion is lighted by the initial light (4), the relative concentration decreasing of the conversion photoluminescence material (15) in the material (2) for conversion is higher then relative decreasing of the secondary light (5) intensity.

EFFECT: invention provides the lighting device with the ability to ensure slightly reduced absorbing capacity for the initial light even if major part of the photoluminescence material discolored, and hence more long service life under the same or slightly reduced intensity of the secondary light.

15 cl, 18 dwg

FIELD: physics.

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

FIELD: physics, optics.

SUBSTANCE: invention discloses a light-emitting device and a method of making said device. The light-emitting device comprises a first layer having top and bottom surfaces, said top surface comprising a first material of a first conductivity type and including a plurality of pits in a substantially flat surface, wherein said top and bottom surfaces are characterised by a distance in between them, which is shorter in said pits than in regions outside said pits; an active layer overlying said top surface of said first layer, wherein said active layer is capable of generating light characterised by a wavelength when holes and electrons recombine therein; a second layer comprising a second material of a second conductivity type, said second layer comprising a top coating layer having top surface and a bottom surface, said bottom surface overlying said active layer and conforming to said active layer, said top surface having depressions therein that extend into said pits; and a substrate on which said first layer is formed, said substrate having a lattice constant sufficiently different from that of the first material to give rise to dislocations in the first layer, wherein said pits are characterised by a bottom point closest to said substrate, said pits arranged such that said bottom point of each of said pits lies at a different one of said dislocations.

EFFECT: high radiation efficiency.

17 cl, 5 dwg

FIELD: electricity.

SUBSTANCE: light-emitting device includes a light-emitting element having a light-conducting element and a multilayered semiconductor part, electrodes located on the multilayered semiconductor part in this order. The light-emitting element includes the first area and the second area on the side of the light-conducting element. The light-conducting element includes the third area and the fourth area on the side of the light-emitting element. The first area has non-uniform location of atoms in comparison to the second area. The third area has non-uniform location of atoms in comparison to the fourth area. The first area is connected directly to the third area.

EFFECT: invention proposes a light-emitting device capable of reducing light attenuation in an element and having high light efficiency, and a manufacturing method of the light-emitting device.

16 cl, 3 dwg

FIELD: physics, optics.

SUBSTANCE: device comprises semiconductor structure with light-emitting ply, luminescent material located on the path of light emitted by light emitting ply and thermal-contact material arranged in translucent material. Note here that thermal-contact material does not convert light-emitting ply light wavelength. Thermal-contact material features higher heat conductivity than that of translucent material. Thermal-contact material is located to dissipate heat from luminescence material. Thermal-contact material features the particle median size larger than 10 mcm. Thermal-contact material refraction ratio differs from that of translucent material by less than 10%.

EFFECT: ruled out undesirable shift of colour hue and reduction in light output.

20 cl, 6 dwg

FIELD: physics.

SUBSTANCE: rendering is carried out by irradiating a sample with two-micron laser radiation, the sample having a spectral absorption band close to the spectral band of the laser radiation. The sample used is powder of a ground monocrystal of CaF2:Ho. The powder is deposited using a binding material on a flat surface which reflects two-micron radiation.

EFFECT: simple method and providing high contrast and resolution in a wide range of radiation power density.

1 dwg

FIELD: chemistry.

SUBSTANCE: light-emitting diode contains epitaxial structure based on solid solutions of nitrides of third group metals, which includes successively placed in direction of epitaxial growth layer of n-type conductivity, active layer with p-n-transition, layer of p-type conductivity, as well as metal contact sites to layer of n-type conductivity, placed in hollows, formed in epitaxial structure at the level of n-type conductivity layer, and light-emitting diode contains metal p-contact layer, intended for its application as positive electrode, applied above p-type conductivity layer, insulation layer, which covers metal p-contact layer and internal side surface of hollows, formed in epitaxial structure, and metal p-contact layer, intended for application as negative electrode, which covers insulation layer and contacts with each metal contact site to p-type conductivity layer, according to invention metal contact areas to n-type conductivity layer in horizontal plane of light-emitting diode section look as two narrow extended belts, each of which is placed on periphery of one of the halves of said section and passes along larger part of its border with indent from it, first and second end parts of one belt are placed with clearance respectively relative to first and second end parts of second belt. Said belts form figure, configuration of which corresponds to configuration of light-emitting diode perimeter, with a gap in its middle part.

EFFECT: increase of current density homogeneity in active area of light-diode and reduction of successive electric resistance.

2 cl, 4 dwg

FIELD: chemistry.

SUBSTANCE: present invention relates to a method of coating a substrate (2), having on its surface a material different from silicone rubber, or consisting of such material, by chemical vapour deposition using a flame. The method includes exposing the substrate to a burner flame (1), to which a stream of precursor elements which enable to obtain coating material is added. Without external cooling, the substrate is moved relative to said flame with a relative speed greater than 30 m/min while allowing the flame to stretch along the reaction zone (3) located behind the burner.

EFFECT: obtaining a coating of good quality, particularly on heat-sensitive materials.

26 cl, 6 dwg

FIELD: physics.

SUBSTANCE: device for converting solar energy includes at least a pair of substrates, each in the form of a strip, wherein at least one of the strips is profiled with a periodically recurring profile which forms a trench-like cavity, and is configured to connect its front surface with the back surface of a second strip. The strips are made of a material which allows their profiling by bending. The strip which is profiled with a periodically recurring profile which forms a trench-like cavity is configured to connect its front surface with the back surface of the second strip and to form, through their profiles, at least one row of trenches and, through strips of one pair, a flexible device for converting solar energy. Profiles of at least one row of trenches are configured to form part of a circle, and/or part of a hyperbola, and/or part of a parabola, and/or trenches with a flat, convex or concave bottom and inclined diverging side walls, wherein all trenches have outward-directed sides on the periphery of the corresponding trench that are perpendicular or inclined relative to an imaginary plane on the edge of the corresponding trench of the first strip, wherein the trenches have on their working surface a photodetector layer and the sides of the trenches have on their surface a photodetector layer or a reflecting coating.

EFFECT: higher efficiency due to the high absorption coefficient of the photodetector layer owing to a larger number of rereflections of radiation from the photodetector layer inside a trench-like three-dimensional structure, reduced dependency of the absorption coefficient on the angle of incidence of solar radiation, simple manufacturing technology, low weight.

14 cl, 6 dwg

FIELD: electricity.

SUBSTANCE: clip connection (1) for fixing on guiding beams (8) of plate-like structural elements (13), in particular solar modules, consists of the support (2) having (1) a stop beam oriented in the longitudinal direction of the clip connection (4) with lateral wing-shaped bars (5, 6) with adjoining surfaces (10, 11) for structural elements (13), and also a toe provided on the lower side (7) for fastening of the support (2) on the beam (8) and also - of the clipping cover (3) with the longitudinal groove (9) covering the top part of the stop beam (4) and with clipping surfaces (13, 14) covering the support (2) adjoining surfaces (10, 11), and with the holding connection (25, 28, 29) for fixing of the clipping cover (3) on the support (2), and the beam (8) has the guiding grooves with the edges (34) protruding inside a groove, and the toe (7) designed as T-shaped one by its cross-piece (36) is inserted into the guiding groove and after 90 turn it is engaged behind protruding edges (34). The support (2) has the pass (24) along the centre of which the spring washer (31) is located which with the power closing takes the pressed, connected with the clipping cover (3) the holding pin (30) and thus fixes a clipping cover (3) on the support (2).

EFFECT: increase of durability.

26 cl, 8 dwg

FIELD: chemistry.

SUBSTANCE: invention relates to novel redox pairs for the application in dye-sensitised solar cells DSSC. The redox pairs are formed by the general formula (bipyridine derivative)nMe(Ion)m, where the bipyridine derivative is where R2, R3 is any substituent from the group methyl, ethyl, propyl, butyl, pentyl, hexyl, Me is a metal from the group Cr, Mo, Nd, Ni, Pd, Pt, Ir, Co, Rh, Cu, W, Mn, Ta, Fe, Ru, Ion - a counterion, is any of the group ClO4-, Cl-, I-, BF4-, PF6-, CF3SO3-, n, m correspond to the metal ion valence. The novel redox pairs (version) and an electrolyte for the application on DSSC are also claimed.

EFFECT: novel redox pairs are applied in DSSC and possess the lowest redox-levels for increasing the open circuit voltage.

3 cl, 1 dwg, 1 tbl, 3 ex

FIELD: power industry.

SUBSTANCE: invention is used for converting of solar energy into electrical energy. The essence of the invention is that the photo-electric converter contains funnelled through holes with the antireflecting coating and the thick-film coating (from the back side) containing the spherical microparticles capable to reflect through sun lights on the verge of through holed.

EFFECT: possibility of increase of efficiency of the photo-electric converter.

4 cl, 3 dwg

FIELD: physics.

SUBSTANCE: proposed concentrator consists of three glass bundles of optical fibres arranged one above the other. Fibres of bundles in solar radiation effects area are distributed uniformly in two and more plies over said area. Said fibres are arranged in more compact manner ahead of intake site of photo inverters. Side of fibre bundles subjected to solar radiation include neutral molecular silver clusters for top bundle, quantum points CdSe or CdSSe for mid bundle and PbS or PbSe for bottom bundle.

EFFECT: higher efficiency of solar radiation capture and conversion in electric power.

7 dwg

FIELD: physics.

SUBSTANCE: this module has protective glass coating and interconnected solar elements arranged between said glass and case with heat exchanger. Solar elements are electrically isolated from heat exchanger. Space between solar elements and heat exchanger and that between glass coating and heat exchanger are filled with the 0.5-5mm-deep ply of siloxane gel. Said protective glass coating is composed of evacuated glass stack of two glasses with vacuum gap of 0.1-0.2 mm with vacuum of 10-3-10-5 mm Hg. Heat exchanger is composed by sealed chamber with heat carrier circulation pipes. Total area of solar elements approximates to the area of heat exchanger case top base. Hybrid photoelectric module solar elements chains can be electrically connected in parallel by switching buses.

EFFECT: higher efficiency of solar energy conversion.

2 cl, 2 dwg

FIELD: physics.

SUBSTANCE: photoconverter element has a plate made of conducting material, sensitised titanium dioxide, a transparent element coated with a conducting coating. The sensitised titanium dioxide is deposited on the plate made of conducting material on both sides and is coated with a transparent element with a conducting coating.

EFFECT: invention increases the efficiency of the photoconverter element, lowers the cost and simplifies production thereof.

1 dwg

FIELD: power engineering.

SUBSTANCE: offered device with photoreceiving layer for conversion of solar energy into electrical one contains, at least, one pair of substrates, each of which is designed as a strip, and, at least, one of strips is made profiled with a periodic profile in its longitudinal direction and variable profile - in a cross direction, meanwhile substrates of the same pair are connected to each other with a possibility of forming by profiles, at least, one row of cavities. The cavities can be cones and/or pyramids and/or spheres and/or spheroids and/or cylinders and/or truncated cones and/or truncated pyramids, meanwhile the cavities in different rows in a cross direction can be made with different shapes. The strip height is less than the profile height of cross and/or longitudinal sections of this strip.

EFFECT: increase of efficiency of the device for conversion of solar energy by means of increase of absorption coefficient of photoreception layer, decrease of dependence of an absorption coefficient from pitch angle of fall of solar radiation at simplification of technology of manufacture, setting and operation of the device, reduction of its weight and cost.

4 cl, 10 dwg

FIELD: physics.

SUBSTANCE: photovoltaic device containing a photovoltaic cell (60) with thin active layers (15) applied on the substrate (10). The named active layers are not segmented, and the static converter (50), connected with each photovoltaic cell (60). Each photovoltaic cell (60) outputs electrical power with a peak current (Icc) and rated voltage (Vp), and each static converter (50) is designed with a possibility of transmission of electrical power, outputted by a photovoltaic cell, to the load (100), decreasing the transmitted current and increasing the transmitted voltage. Meanwhile the active layers of photovoltaic cell cover more than 95% of the layer area, and the named photovoltaic cell is capable to produce a current achieving 150 A at a voltage rating below 1 V. Therefore, on one panel the laser segmentation of photovoltaic cells is limited and even completely eliminated.

EFFECT: increased productivity of manufacture of the photovoltaic device and minimizing the dead areas.

18 cl, 8 dwg

FIELD: chemistry.

SUBSTANCE: first step includes obtaining low-hydroxylated insoluble fullerenols by reacting concentrated fullerene solution in o-xylene with aqueous ammonia solution in the presence of a tetrabutylammonium hydroxide phase-transfer catalyst at 35-40°C. At the second step, the obtained low-hydroxylated insoluble fullerenols are hydroxylated to transform them into a water-soluble form by mixing with 6-15% aqueous hydrogen peroxide solution and heating for 4-5 hours at 65°C. Water-soluble fullerenols are then precipitated from an alcohol-containing solution.

EFFECT: simplifying the method while preserving quality characteristics and full extraction of the end product.

2 cl, 1 dwg, 4 tbl, 3 ex

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