Abstract: A semiconductor device is provided comprising a first potential well located within a pn junction and a second potential well not located within a pn junction. The potential wells may be quantum wells. The semiconductor device is typically an LED, and may be a white or near-white light LED. The semiconductor device may additionally comprise a third potential well not located within a pn junction. The semiconductor device may additionally comprise absorbing layers surrounding or closely or immediately adjacent to the second or third quantum wells. In addition, graphic display devices and illumination devices comprising the semiconductor device according to the present invention are provided.

Abstract: An LED made from a wide band gap semiconductor material and having a low resistance p-type confinement layer with a tunnel junction in a wide band gap semiconductor device is disclosed. A dissimilar material is placed at the tunnel junction where the material generates a natural dipole. This natural dipole is used to form a junction having a tunnel width that is smaller than such a width would be without the dissimilar material. A low resistance p-type confinement layer having a tunnel junction in a wide band gap semiconductor device may be fabricated by generating a polarization charge in the junction of the confinement layer, and forming a tunnel width in the junction that is smaller than the width would be without the polarization charge. Tunneling through the tunnel junction in the confinement layer may be enhanced by the addition of impurities within the junction. These impurities may form band gap states in the junction.

Abstract: Provided are a light emitting device, a light emitting device package and a lighting system including the same. The light emitting device (LED) comprises a substrate, a second conductive type semiconductor layer, an active layer, a first conductive type semiconductor layer and a first electrode. The vertical distances between the first conductive type semiconductor layer and the second conductive type semiconductor layer are varied.

Abstract: A light-emitting device epitaxial wafer includes an n-type substrate, an n-type cladding layer stacked on the n-type substrate, a light-emitting layer including a quantum well structure stacked on the n-type cladding layer, and a p-type cladding layer stacked on the light-emitting layer. The n-type cladding layer includes an epitaxial layer doped with a mixture of 2 or more n-type dopants including Si, and is not less than 250 nm and not more than 750 nm in thickness. Alternatively, a light-emitting device epitaxial wafer includes an n-type substrate, an n-type cladding layer stacked on the n-type substrate, a light-emitting layer stacked on the n-type cladding layer, and a p-type cladding layer stacked on the light-emitting layer. The n-type cladding layer includes 2 or more n-type impurities including Si.

Abstract: A lateral thermal dissipation LED and a fabrication method thereof are provided. The lateral thermal dissipation LED utilizes a patterned metal layer and a lateral heat spreading layer to transfer heat out of the LED. The thermal dissipation efficiency of the LED is increased, and the lighting emitting efficiency is accordingly improved.

Abstract: A semiconductor nanocrystal compound and probe are described. The compound is capable of linking to one or more affinity molecules. The compound comprises (1) one or more semiconductor nanocrystals capable of, in response to exposure to a first energy, providing a second energy, and (2) one or more linking agents, having a first portion linked to the one or more semiconductor nanocrystals and a second portion capable of linking to one or more affinity molecules. One or more semiconductor nanocrystal compounds are linked to one or more affinity molecules to form a semiconductor nanocrystal probe capable of bonding with one or more detectable substances in a material being analyzed, and capable of, in response to exposure to a first energy, providing a second energy. Also described are processes for respectively: making the semiconductor nanocrystal compound; making the semiconductor nanocrystal probe; and treating materials with the probe.

Abstract: A light emitting diode chip comprising a light emitting diode and a thermally conductive substrate. The light emitting diode is on the substrate with the substrate providing a thermal path from the light emitting diode through the substrate. A mounting pad is also on a substrate and an electrically insulating layer is integral to the substrate. The insulating layer electrically insulates the mounting pad from the light emitting diode. A method for fabricating a light emitting diode chip comprises providing a thermally conductive substrate, forming an electrical insulating layer integral to the substrate and forming a mounting pad on the substrate. A light emitting diode is fabricated and mounted to the substrate, with the light emitting diode electrically insulated from the mounting pad by the electrically insulating layer.

Abstract: Provided is an electroluminescent device which has a luminescent layer including quantum dots and which are excellent in life characteristics. An electroluminescent device (1) comprises a first electrode layer (3), a luminescent layer (4) formed on the first electrode layer, and a second electrode layer (5) formed on the luminescent layer. The luminescent layer uses quantum dots (12), each quantum dot being surrounded by silane coupling agent (11).

Abstract: Disclosed are a semiconductor light emitting device and a method for manufacturing the same. The semiconductor light emitting device comprises a substrate, in which concave-convex patterns are in at least a portion of a backside of the substrate, and a light emitting structure on the substrate and comprising a first conductive semiconductor layer, an active layer and a second conductive semiconductor layer.

Abstract: One aspect of the present invention provides a semiconductor light-emitting device improved in luminance, and also provides a process for production thereof. The process comprises a procedure of forming a relief structure on the light-extraction surface of the device by use of a self-assembled film. In that procedure, the light-extraction surface is partly covered with a protective film so as to protect an area for an electrode to be formed therein. The electrode is then finally formed there after the procedure. The process thus reduces the area incapable, due to thickness of the electrode, of being provided with the relief structure. Between the electrode and the light-extraction surface, a contact layer is formed so as to establish ohmic contact between them.

Abstract: One embodiment of the present invention provides a semiconductor light-emitting element having both high light-extraction efficiency and excellent adhesion between a light-extraction surface and a sealing resin, and it also provides a process for production thereof. This element comprises a semiconductor multilayered film and a light-extraction surface. In the multilayered film, plural semiconductor layers and an active layer are stacked. The light-extraction surface is provided on the multilayered film, and plural micro-projections are formed thereon. These micro-projections have flat top faces parallel to the multilayered film, and they can be formed by an etching process. The etching process is performed by use of a dot pattern as a mask, and the dot pattern is formed by phase separation of a block copolymer.

Abstract: Provided is a semiconductor element which can suppress deterioration of element characteristics even when a semiconductor element section includes a plurality of directions having different thermal expansion coefficients within an in-plane direction. A semiconductor laser element (the semiconductor element) is provided with the semiconductor element section, which includes a direction of [1-100] and a direction of [0001] having different thermal expansion coefficients within the in-plane direction of a main surface, and a sub-mount, which includes an arrow (E) direction and an arrow (F) direction having different thermal expansion coefficients within the in-plane direction of the main surface. The semiconductor element section is bonded on the sub-mount so that the direction [1-100] of the semiconductor element section is close to the side of the arrow (E) direction than the arrow (F) direction of the sub-mount.

Abstract: Provided is a semiconductor light emitting device and a method for manufacturing the same. The semiconductor light emitting device includes a light emitting structure, an insulating substrate, a first electrode, a second electrode, and a conductive supporting substrate. The light emitting structure includes a first conductive semiconductor layer, an active layer, and a second conductive semiconductor layer. The insulating substrate is formed on the light emitting structure to include a contact groove. The first electrode is formed on the insulating substrate. The second electrode is formed under the light emitting structure. The conductive supporting substrate is formed under the second electrode.

Abstract: A nitride semiconductor light emitting diode includes a p-type layer 103 made of a p-type nitride semiconductor, a light emission layer 102 provided on a lower surface of the p-type layer 103, an n-type layer 101 made of an n-type nitride semiconductor provided on a lower surface of the light emission layer 102, and a bonding layer 114 provided, contacting the n-type layer 101. An uneven topography having a plurality of sloped surface is provided on a surface contacting the bonding layer 114 of the n-type layer 101. The bonding layer 114 is made of a metal made of Group III atoms or an alloy containing the Group III atoms.

Abstract: LED devices incorporating diamond materials and methods for making such devices are provided. One such method may include forming epitaxially a substantially single crystal SiC layer on a substantially single crystal Si wafer, forming epitaxially a substantially single crystal diamond layer on the SiC layer, doping the diamond layer to form a conductive diamond layer, removing the Si wafer to expose the SiC layer opposite to the conductive diamond layer, forming epitaxially a plurality of semiconductor layers on the SiC layer such that at least one of the semiconductive layers contacts the SiC layer, and coupling an n-type electrode to at least one of the semiconductor layers such that the plurality of semiconductor layers is functionally located between the conductive diamond layer and the n-type electrode.

Abstract: A display device with pixels capable of uniform light emission and a method of making the display device are presented. A display device has a plurality of TFTs, a protection layer formed on the TFTs, and a plurality of pixel electrodes formed on the protection layer and electrically connected to the TFTs. A wall is formed around the pixel electrode and at least a portion of the wall is spaced from the pixel electrode. A light emitting layer is formed between the wall and another wall.

Abstract: In the nitride based semiconductor optical device LE1, the strained well layers 21 extend along a reference plane SR1 tilting at a tilt angle ? from the plane that is orthogonal to a reference axis extending in the direction of the c-axis. The tilt angle ? is in the range of greater than 59 degrees to less than 80 degrees or greater than 150 degrees to less than 180 degrees. A gallium nitride based semiconductor layer P is adjacent to a light-emitting layer SP? with a negative piezoelectric field and has a band gap larger than that of a barrier layer. The direction of the piezoelectric field in the well layer W3 is directed in a direction from the n-type layer to the p-type layer, and the piezoelectric field in the gallium nitride based semiconductor layer P is directed in a direction from the p-type layer to the n-type layer. Consequently, the valence band, not the conduction band, has a dip at the interface between the light-emitting layer SP? and the gallium nitride based semiconductor layer P.

Abstract: A light-emitting device including: a light-emitting stacked layer having first conductivity type semiconductor layer, a light-emitting layer formed on the first conductivity type semiconductor layer, and a second conductivity type semiconductor layer formed on the light-emitting layer, wherein the upper surface of the second conductivity type semiconductor layer is a textured surface; a first planarization layer formed on a first partial of the upper surface of the second conductivity type semiconductor layer; a first transparent conductive oxide layer formed on the first planarization layer and a second partial of the second conductivity type semiconductor layer, including a first portion in contact with the first planarization layer and a second portion having a first plurality of cavities in contact with the second conductivity type semiconductor layer; and a first electrode formed on the first portion of the first transparent conductive oxide layer.

Abstract: Provided is a method of manufacturing a vertical light emitting device.

Abstract: A nitride semiconductor laser element includes a substrate and a nitride semiconductor layer in which a first semiconductor layer, an active layer, and a second semiconductor layer are laminated in this order on the substrate. At least one of the first semiconductor layer and the second semiconductor layer includes a first section forming recessed and raised portions and a second section embedding the recessed and raised portions of the first section. A region with a higher aluminum mixed crystal ratio than the second section that embeds the recessed and raised portions is disposed on top faces of the raised portions. The nitride semiconductor layer defines resonant planes, and the recessed and raised portions are formed in a shape of stripes that extend substantially parallel to the resonant planes.

Abstract: A facet extraction LED improved in light extraction efficiency and a manufacturing method thereof. A substrate is provided. A light emitting part includes an n-type semiconductor layer, an active layer and a p-type semiconductor layer sequentially stacked on the substrate. A p-electrode and an n-electrode are connected to the p-type semiconductor layer and the n-type semiconductor layer, respectively. The p- and n-electrodes are formed on the same side of the LED. The light emitting part is structured as a ring.

Abstract: The embodiment discloses a semiconductor light emitting device. The semiconductor light emitting device includes a first conductive semiconductor layer; a first electrode layer below the first conductive semiconductor layer; a semiconductor layer at an outer peripheral portion of the first conductive semiconductor layer; an active layer on the first conductive semiconductor layer; a second conductive semiconductor layer on the active layer; and a second electrode layer on the second conductive semiconductor layer.

Abstract: Provided are a semiconductor device, a semiconductor device manufacturing method, a high carrier mobility transistor and a light emitting device. The semiconductor device is provided with a semiconductor layer including N and Ga, a conductive layer ohmic-connected to the semiconductor layer, a metal-distributed region where metal exists by being distributed at an interface between the semiconductor layer and the conductive layer, and a metal intrusion region where the atoms of the metal exist by entering the semiconductor layer.

Abstract: The invention provides a quantum well active region for an optoelectronic device. The quantum well active region includes barrier layers of high bandgap material. A quantum well of low bandgap material is between the barrier layers. Three-dimensional high bandgap barriers are in the quantum well. A preferred semiconductor laser of the invention includes a quantum well active region of the invention. Cladding layers are around the quantum well active region, as well as a waveguide structure.

Abstract: A light-emitting structure includes a p-doped region for injecting holes and an n-doped region for injecting electrons. At least one InGaN quantum well of a first type and at least one InGaN quantum well of a second type, are arranged between the n-doped region and the p-doped region. The InGaN quantum well of the second type has a higher indium content than the InGaN quantum well of the first type.

Abstract: A light emitting device includes a substrate having a first surface and a second surface not parallel to the first surface, and a light emission layer disposed over the second surface to emit light. The light emission layer has a light emission surface which is not parallel to the first surface.

Abstract: A semiconductor light-emitting device (LE1) comprises a multilayer structure LS generating light. This multilayer structure includes a plurality of laminated compound semiconductor layers (3 to 8) and has first and second main faces (61, 62) opposing each other. A first electrode (21) and a second electrode (31) are arranged on the first and second main faces, respectively. A film made of silicon oxide (10) is also formed on the first main face so as to cover the first electrode. A glass substrate (1) optically transparent to the light generated by the multilayer structure is secured to the multilayer structure through the film made of silicon oxide.

Abstract: An organic light emitting diode display with first and second substrates, and a method of manufacturing the organic light emitting diode display. The first substrate has a plurality of first organic light emitting diodes each having a first emissive area and a first non-emissive area, and a first driving circuit unit for driving the first organic light emitting diodes. The second substrate has a plurality of second organic light emitting diodes each having a second emissive area and a second non-emissive area, and a second driving circuit unit for driving the second organic light emitting diodes. The first emissive areas of the first organic light emitting diodes face the second non-emissive areas of the second organic light emitting diodes, respectively, and the second emissive areas of the second organic light emitting diodes face the first nonemissive area of the first organic light emitting diodes, respectively.

Abstract: In accordance with the invention, a light source for display and/or illumination is provided, the light source comprising a heterostructure including semiconductor layers, the heterostructure forming a waveguide between a first end and a second end, the heterostructure comprising a plurality of layers and comprising an optically active zone formed by the plurality of layers, the optically active zone capable of emitting light guided by said waveguide, at least two different radiative transitions being excitable in the optically active an electrical current between a p-side electrode and an n-side electrode, transition energies of said at least two different radiative transitions corresponding to wavelengths in the visible part of the optical spectrum, the light source further comprising means for preventing reflections of light from the waveguide by at least one of said first and second end back into the waveguide, thereby causing the light source to comprise a superluminescent light emitting diode.

Abstract: Provided are a semiconductor light emitting device and a method of fabricating the same. The semiconductor light emitting device comprises a first conductive semiconductor layer, an active layer on the first conductive semiconductor layer, a second conductive semiconductor layer, and an electrode layer comprising a conductive polymer on the second conductive semiconductor layer.

Abstract: There is provided a semiconductor light emitting device, a method of manufacturing the same, and a semiconductor light emitting device package using the same. A semiconductor light emitting device having a first conductivity type semiconductor layer, an active layer, a second conductivity type semiconductor layer, a second electrode layer, and insulating layer, a first electrode layer, and a conductive substrate sequentially laminated, wherein the second electrode layer has an exposed area at the interface between the second electrode layer and the second conductivity type semiconductor layer, and the first electrode layer comprises at least one contact hole electrically connected to the first conductivity type semiconductor layer, electrically insulated from the second conductivity type semiconductor layer and the active layer, and extending from one surface of the first electrode layer to at least part of the first conductivity type semiconductor layer.

Abstract: A method for manufacturing a light emitting device according to the present invention has the steps of: preparing a first member which has an emission layer on a substrate having a compound semiconductor layer through an etch stop layer and a sacrifice layer; forming a bonded structure by bonding the first member on a second member including a silicon layer so that the emission layer is positioned in the inner side; providing a through groove in the substrate so that the etch stop layer is exposed, by etching the first member from the reverse side of the emission layer; and removing the substrate having the through groove provided therein from the bonded structure by etching the sacrifice layer.

Abstract: Provided is a semiconductor light emitting device and a method of fabricating the same. The semiconductor light emitting device comprises: a first conductive semiconductor layer; an active layer on the first conductive semiconductor layer; a second conductive semiconductor layer on the active layer; a second electrode part on the second conductive semiconductor layer; an insulation layer on the second electrode part; and a first electrode part on the insulation layer, a portion of the first electrode part being electrically connected to the first conductive semiconductor layer.

Abstract: A nitride semiconductor-based light emitting device is provided. The nitride semiconductor-based light emitting device is formed of a nitride semiconductor having a wurtzite lattice structure with the Ga face. The device has a substrate, a buffer layer, a first p-type contact layer, a second p-type contact layer, a first hole diffusion layer, a second hole diffusion layer, a light emitting active region, a second electron diffusion layer, a first electron a first n-type contact layer, which are sequentially stacked. Such a structure may effectively employ quasi-two-dimensional free electron and free hole gases formed at heterojunction interfaces due to the spontaneous polarization and the piezoelectric polarization in the wurtzite lattice structure with the Ga face, and thus enhances the emission uniformity and emission efficiency of the light emitting device.

Abstract: Provided are a semiconductor light emitting device and a method of fabricating the same. The semiconductor light emitting device comprises: a light emitting structure comprising a first conductive semiconductor layer, an active layer on the first conductive semiconductor layer, and a second conductive semiconductor layer on the active layer; a nitride semiconductor layer on an outer periphery of the second conductive semiconductor layer; and an ohmic layer on the second conductive semiconductor layer.

Abstract: A semiconductor light emitting device and a method of manufacturing the same are provided. The semiconductor light emitting device comprises a first semiconductor layer emitting electrons, a second semiconductor layer emitting holes, and an active layer emitting light by combination of the electrons and holes. At least one of the layers comprises an photo enhanced minority carriers.

Abstract: A radiation-emitting semiconductor chip is specified, comprising a semiconductor body (3) having an n-conducting region (4) and a p-conducting region (5), the semiconductor body having a hole barrier layer containing a material from the material system InyGa1-x-yAlxN.

Abstract: An LED is provided comprising two or more light-emitting Type II interfaces wherein at least two of the Type II interfaces differ in transition energy by at least 5%, or more typically by at least 10%, and wherein at least one of the Type II interfaces is within a pn junction. Alternately, an LED is provided comprising two or more light-emitting Type II interfaces wherein at least two of the Type II interfaces differ in transition energy by at least 5%, or more typically by at least 10%. The Type II interfaces may include interfaces from a layer which is an electron quantum well and not a hole quantum well, interfaces to a layer which is a hole quantum well and not an electron quantum well; and interfaces that satisfy both conditions simultaneously. The Type II interfaces may be within a pn or pin junction or not within a pn or pin junction. In the later case, emission from the Type II interfaces may be photopumped by a nearby light source. The LED may be a white or near-white light LED.

Abstract: A manufacture method for zinc oxide (ZnO) based semiconductor crystal includes providing a substrate having a Zn polarity plane; and reacting at least zinc (Zn) and oxygen (O) on the Zn polarity plane of said substrate to grow ZnO based semiconductor crystal on the Zn polarity plane of said substrate in a Zn rich condition. (a) An n-type ZnO buffer layer is formed on a Zn polarity plane of a substrate. (b) An n-type ZnO layer is formed on the surface of the n-type ZnO buffer layer. (c) An n-type ZnMgO layer is formed on the surface of the n-type ZnO layer. (d) A ZnO/ZnMgO quantum well layer is formed on the surface of the n-type ZnMgO layer, by alternately laminating a ZnO layer and a ZnMgO layer. @(e) A p-type ZnMgO layer is formed on the surface of the ZnO/ZnMgO quantum well layer. (f) A p-type ZnO layer is formed on the surface of the p-type ZnMgO layer. @(g) An electrode is formed on the n-type ZnO layer and p-type ZnO layer. The n-type ZnO layer is formed under a Zn rich condition at the step (b).

Abstract: An object of the present invention is to provide a gallium nitride-based compound semiconductor light emitting device having superior light extraction efficiency and light distribution uniformity. The inventive gallium nitride-based compound semiconductor light emitting device comprises a substrate and a gallium nitride-based compound semiconductor layer stacked on the substrate, wherein on at least one lateral surface of the light emitting device, the bottom (substrate side) of the semiconductor layer is a reverse taper inclined 5 to 85 degrees relative to the substrate main surface and the top of the semiconductor layer is a forward taper inclined 95 to 175 degrees relative to the substrate main surface.

Abstract: A method for fabricating a nitride semiconductor light emitting device, and a nitride semiconductor light emitting device fabricated thereby are provided. The method includes: forming a first conductive nitride semiconductor layer on a substrate; forming an active layer on the first conductive nitride semiconductor layer; forming a second conductive nitride semiconductor layer on the active layer; and lowering a temperature while adding oxygen to the result by performing a thermal process.

Abstract: A semiconductor light emitting device includes a silicon substrate, a p-type semiconductor layer provided on the silicon substrate, a n-type semiconductor layer provided on the silicon substrate, the n-type semiconductor layer adjoining the p-type semiconductor layer, and a light emitting section formed at a p-n homojunction between the p-type semiconductor layer and the n-type semiconductor layer. The p-n homojunction is substantially perpendicular to a major surface of the silicon substrate. The p-n homojunction is corrugated with a period matched with an integer multiple of an emission wavelength at the light emitting section.

Abstract: A fabrication method of a surface-emitting laser element includes a step of preparing a conductive GaN multiple-region substrate including a high dislocation density high conductance region, a low dislocation density high conductance region and a low dislocation density low conductance region, as a conductive GaN substrate; a semiconductor layer stack formation step of forming a plurality of group III-V compound semiconductor layer stack including an emission layer on the substrate; and an electrode formation step of forming a semiconductor side electrode and a substrate side electrode. The semiconductor layer and electrodes are formed such that an emission region into which carriers flow in the emission layer is located above and within the span of the low dislocation density high conductance region. Thus, a surface-emitting laser element having uniform light emission at the emission region can be obtained with favorable yield.

Abstract: Provided is a semiconductor light emitting device. The semiconductor light emitting device comprises a second electrode layer; a light emitting structure comprising a plurality of compound semiconductor layers under the second electrode layer; at least one dividing groove that divides inner areas of the lower layers of the light emitting structure into a plurality of areas; and a first electrode under the light emitting structure.

Abstract: In the Group III nitride-based compound semiconductor light-emitting device of the invention, an non-light-emitting area is formed in a light-emitting layer. In a light-emitting diode where light is extracted on the side of an n-layer, an outer wiring trace portion and an inner wiring trace portion of an n-contact electrode impedes light emission from the light-emitting layer. Therefore, there are provided, at the interface between a p-layer and a p-contact electrode, high-resistance faces having a width wider than the orthogonal projections of contact areas between the outer and inner wiring trace portions and the n-layer on the interface between the p-contact electrode and the p-layer. Through this configuration, current flow is limited, and portions having a total area equivalent to that of the high-resistance faces of the light-emitting layer serve as non-light-emitting areas.

Abstract: Disclosed is a light emitting device. The light emitting device includes a light emitting structure comprising an active layer to generate first light, a first conductive semiconductor layer on the active layer, and a second conductive semiconductor layer on the active layer so that the active layer is disposed between the first and second conductive semiconductor layers, wherein a portion of the light emitting structure is implanted with at least one element which generates second light from the first light.

Abstract: A light emitting device having a vertical structure, which includes a semiconductor layer having a first surface and a second surface, a first electrode arranged on the first surface of the semiconductor layer, a transparent conductive oxide (TCO) layer arranged on the second surface of the semiconductor layer and a second electrode arranged on the TCO layer.

Abstract: A multichip light-emitting diode (LED) includes a reflective cup, a plurality of light-emitting chips and a package. The light-emitting chips are disposed in the reflective cup and emit light when driven. The package is disposed in the reflective cup and covers the light-emitting chips. The package further has a plurality of lenses corresponding to the light-emitting chips one by one. The lenses refract light emitted by the corresponding light-emitting chips, respectively. An extrinsic light efficiency of the multichip is increased through the design of the multichip LED.

Abstract: A display substrate according to the present invention comprises a gate line formed on a substrate. a data line, a thin film transistor connected to the gate line and the data line respectively and pixel electrode connected to the thin film transistor, wherein a channel of the thin film transistor is formed in a direction perpendicular to the substrate and, a layer where the channel is formed includes an oxide semiconductor pattern. ON current of thin film transistor of the display substrate can be increased without loss of aperture ratio.

Abstract: A method for improved growth of a semipolar (Al,In,Ga,B)N semiconductor thin film using an intentionally miscut substrate. Specifically, the method comprises intentionally miscutting a substrate, loading a substrate into a reactor, heating the substrate under a flow of nitrogen and/or hydrogen and/or ammonia, depositing an InxGa1-xN nucleation layer on the heated substrate, depositing a semipolar nitride semiconductor thin film on the InxGa1-xN nucleation layer, and cooling the substrate under a nitrogen overpressure.