Abstract: A method of manufacturing a display system includes forming a display element having a display active area over a silicon backplane, forming a display driver integrated circuit (DDIC), and bonding the display element to the display driver integrated circuit (DDIC). The display active area may include a light emitting diode such as an organic light emitting diode (OLED). Separately forming the display and the display circuitry may simplify formation of the OLED and allow for a higher density control interface between the display and the DDIC.

Abstract: A gallium-containing nitride crystals are disclosed, comprising: a top surface having a crystallographic orientation within about 5 degrees of a plane selected from a (0001)+c-plane and a (000-1)?c-plane; a substantially wurtzite structure; n-type electronic properties; an impurity concentration of hydrogen greater than about 5×1017 cm?3, an impurity concentration of oxygen between about 2×1017 cm?3 and about 1×1020 cm?3, an [H]/[O] ratio of at least 0.3; an impurity concentration of at least one of Li, Na, K, Rb, Cs, Ca, F, and Cl greater than about 1×1016 cm?3, a compensation ratio between about 1.0 and about 4.0; an absorbance per unit thickness of at least 0.

Abstract: The invention comprises a light emitting diode chip and a package substrate. The light emitting diode chip is provided with a semiconductor epitaxial structure, a lateral extending interface structure, a chip conductive structure, an N-type electrode located above the semiconductor epitaxial structure and a P-type bypass detection electrode located on the lateral extending interface structure. The chip conductive structure is provided with a P-type main electrode located on a lower side. The package substrate comprises a plurality of electrode contacts through which the N-type electrode, the P-type bypass detection electrode and the P-type main electrode are connected, and a process quality of a alternative substrate adhesive layer in one of the semiconductor epitaxial structure and the chip conductive structure and a chip-substrate bonding adhesive layer between the P-type main electrode and the package substrate is evaluated by detecting electrical characteristics.

Abstract: Structures and methods for controlling dopant diffusion and activation are disclosed. In one example, a semiconductor structure is disclosed. The semiconductor structure includes: a channel layer; a barrier layer over the channel layer; a gate electrode over the barrier layer; and a doped layer formed between the barrier layer and the gate electrode. The doped layer includes (a) an interface layer in contact with the barrier layer and (b) a main layer between the interface layer and the gate electrode. The doped layer comprises a dopant whose doping concentration in the interface layer is lower than that in the main layer.

Abstract: A power generation element includes a first crystal region including Alx1Ga1-x1N (0<x1?1), and a second crystal region including a first element and Alx2Ga1-x2N (0?x2<x1). The first element includes at least one selected from the group consisting of Si, Ge, Te, and Sn. The first crystal region includes a first surface and a second surface. The second surface is between the second crystal region and the first surface. The second crystal region includes a third surface and a fourth surface. The third surface is between the fourth surface and the first crystal region. An orientation from the fourth surface toward the third surface is along a <0001> direction of the second crystal region. An orientation from the second surface toward the first surface is along a <000-1> direction of the first crystal region.

Abstract: Photonic devices having a photonic waveguiding layer, and a cladding layer, disposed on the photonic waveguiding layer, and where the cladding section is a material comprising Scandium. The cladding layer may include a material comprising Al1-xScxN material where 0<x?0.45.

Abstract: A light emitting apparatus includes an electrode and a laminated structure. The laminated structure includes an n-type first semiconductor layer, a light emitting layer, a p-type second semiconductor layer, a tunnel junction layer, and an n-type third semiconductor layer. The electrode is electrically connected to the first semiconductor layer. The first semiconductor layer, the light emitting layer, the second semiconductor layer, the tunnel junction layer, and the third semiconductor layer are arranged in a presented order. The light emitting layer and the first semiconductor layer form a columnar section.

Abstract: A light-emitting element includes: a first n-type nitride semiconductor layer; a first light-emitting layer located on the first n-type nitride semiconductor layer; a p-type GaN layer located on the first light-emitting layer; an n-type GaN layer located on the p-type GaN layer and doped with an n-type impurity at an impurity concentration higher than that of the first n-type nitride semiconductor layer; a non-doped GaN layer located between the p-type GaN layer and the n-type GaN layer, a thickness of the non-doped GaN layer being not more than a width of a depletion layer formed by the n-type and p-type GaN layers; a second n-type nitride semiconductor layer located on the n-type GaN layer and doped with an n-type impurity; a second light-emitting layer located on the second n-type nitride semiconductor layer; and a p-type nitride semiconductor layer located on the second light-emitting layer and doped with a p-type impurity.

Abstract: A laser diode and a method for manufacturing a laser diode are disclosed. In an embodiment a laser diode includes a surface emitting semiconductor laser configured to emit electromagnetic radiation and an optical element arranged downstream of the semiconductor laser in a radiation direction, wherein the optical element includes a diffractive structure or a meta-optical structure or a lens structure, and wherein the optical element and the semiconductor laser are cohesively connected to each other.

Abstract: The present invention relates to a silicon carbide (SiC) substrate with improved mechanical and electrical characteristics. Furthermore, the invention relates to a method for producing a bulk SiC crystal in a physical vapor transport growth system. The silicon carbide substrate comprises an inner region (102) which constitutes at least 30% of a total surface area of said substrate (100), a ring shaped peripheral region (104) radially surrounding the inner region (102), wherein a mean concentration of a dopant in the inner region (102) differs by at maximum 5·1018 cm?3, preferably 1·1018 cm?3, from the mean concentration of this dopant in the peripheral region (104).

Abstract: A nitride semiconductor light-emitting element includes an n-type cladding layer including n-type AlGaN having a first Al composition ratio, a barrier layer including AlGaN that is located on the n-type cladding layer side in a multiple quantum well layer and has a second Al composition ratio greater than the first Al composition ratio, and a graded layer that is located between the n-type cladding layer and the barrier layer and has a third Al composition ratio that is between the first Al composition ratio and the second Al composition ratio, wherein the third Al composition ratio of the graded layer increases at a predetermined increase rate from the first Al composition ratio toward the second Al composition ratio.

Abstract: A method of manufacturing a display system includes forming a display element having a display active area over a silicon backplane, forming a display driver integrated circuit (DDIC), and bonding the display element to the display driver integrated circuit (DDIC). The display active area may include a light emitting diode such as an organic light emitting diode (OLED). Separately forming the display and the display circuitry may simplify formation of the OLED and allow for a higher density control interface between the display and the DDIC.

Abstract: A semiconductor nanocrystal structure may include a core, an inner absorption shell surrounding the core, at least one emission shell surrounding the inner absorption shell, and an outer absorption shell surrounding the emission shell(s). The core may include a different material than the optional inner absorption shell and/or the outer absorption shell. The core may be less absorbent to electromagnetic radiation as compared to the optional inner absorption shell and/or the outer absorption shell. An optoelectronic device may include the semiconductor nanocrystal structure.

Abstract: This invention opens up the chip thickness for increasing VCSEL power. It describes a method by using multiple gain layers 10, separated by insulating layers 11, powered in parallel electrically through embedded electrodes 13, 14 connected through via holes. The gain layers, as a whole, are bounded on top and bottom by DBR mirrors 12. The structure, compared to a standard VCSEL, leads to higher power, lower resistive loss, higher device speed, higher beam quality, and fewer number of DBR layers.

Abstract: An optoelectronic component, a method for manufacturing an optoelectronic component and a method for operating an optoelectronic component are disclosed. In an embodiment, the component includes a carrier comprising a molded body and a light-emitting semiconductor body with a first segment and a second segment, wherein the first segment and the second segment are spatially separated from one another, and wherein each segment has an emission side facing away from the carrier. The component further includes a first electrical conductor path arranged on the first segment and on the second segment on a side of the light-emitting semiconductor body facing towards the carrier and a first electrical connecting structure and a second electrical connecting structure, each electrically connecting the first segment and the second segment to one another, wherein the first and second electrical connecting structure are electrically connected to one another by the first electrical conductor path.

Abstract: A light emitting device includes: a plurality of light emitting stacked layers, including a first surface and a second surface, wherein the second surface is electrically opposite to the first surface; a mesa structure; and a current blocking (CB) layer disposed on the first surface; a transparent conductive layer disposed on or above the first surface; and a first pad electrode, disposed on the transparent conductive layer and on the first surface; wherein a sidewall of the CB layer comprises a first surface section and a second surface section having different slopes.

Abstract: A compound semiconductor has a high electron concentration of 5×1019 cm?3 or higher, exhibits an electron mobility of 46 cm2/V·s or higher, and exhibits a low electric resistance, and thus is usable to produce a high performance semiconductor device. The present invention provides a group 13 nitride semiconductor of n-type conductivity that may be formed as a film on a substrate having a large area size at a temperature of room temperature to 700° C.

Abstract: Techniques are disclosed for forming tunable capacitors including multiple two-dimensional electron gas (2DEG) and three-dimensional electron gas (3DEG) structures for use in tunable radio frequency (RF) filters. In some cases, the tunable capacitors include a stack of group III material-nitride (III-N) compound layers that utilize polarization doping to form the 2DEG and 3DEG structures. In some instances, the structures may be capable of achieving at least three capacitance values, enabling the devices to be tunable. In some cases, the tunable capacitor devices employing the multi-2DEG and 3DEG structures may be a metal-oxide-semiconductor capacitor (MOSCAP) or a Schottky diode, for example. In some cases, the use of tunable RF filters employing the multi-2DEG and 3DEG III-N tunable capacitor devices described herein can significantly reduce the number of filters in an RF front end, resulting in a smaller physical footprint and reduced bill of materials cost.

Abstract: A semiconductor layer sequence is disclosed. In an embodiment the semiconductor layer sequence includes an n-conducting n-region, a p-conducting p-region and an active zone having at least one quantum well located between the n-region and the p-region, wherein the semiconductor layer sequence includes AlInGaN, wherein the n-region comprises a superlattice, wherein the superlattice has a structural unit which repeats at least three times, wherein the structural unit comprises at least one AlGaN layer, at least one GaN layer and at least one InGaN layer, wherein an intermediate layer is disposed between the active zone and the superlattice, wherein the intermediate layer comprises either n-doped GaN or n-doped GaN together with n-doped InGaN so that the intermediate layer is free of aluminum, and wherein the intermediate layer directly adjoins the active zone and the superlattice.

Abstract: A method for manufacturing an optoelectronic component includes providing a growth substrate; applying a succession of semiconductor layers; structuring the succession of semiconductor layers; applying a sacrificial layer; depositing a metal layer; optionally planarizing using a dielectric material; forming a second terminal contact through the active region; applying a permanent support; and detaching the growth substrate and exposing the metal layer.

Abstract: Described herein are methods for using remote plasma chemical vapor deposition (RP-CVD) and sputtering deposition to grow layers for light emitting devices. A method includes growing a light emitting device structure on a growth substrate, and growing a tunnel junction on the light emitting device structure using at least one of RP-CVD and sputtering deposition. The tunnel junction includes a p++ layer in direct contact with a p-type region, where the p++ layer is grown by using at least one of RP-CVD and sputtering deposition. Another method for growing a device includes growing a p-type region over a growth substrate using at least one of RP-CVD and sputtering deposition, and growing further layers over the p-type region. Another method for growing a device includes growing a light emitting region and an n-type region using at least one of RP-CVD and sputtering deposition over a p-type region.

Abstract: An embodiment of the present invention includes: a gallium nitride substrate; and a light-emitting structure disposed on the other surface of the substrate, wherein the substrate includes a plurality of light extraction structures formed on one surface thereof, the thickness of the substrate is 80 ?m or more, and the average height of the plurality of light extraction structures is 10 ?m or more.

Abstract: Described herein are methods for growing light emitting devices under ultra-violet (UV) illumination. A method includes growing a III-nitride n-type layer over a III-nitride p-type layer under UV illumination. Another method includes growing a light emitting device structure on a growth substrate and growing a tunnel junction on the light emitting device structure, where certain layers are grown under UV illumination. Another method includes forming a III-nitride tunnel junction n-type layer over the III-nitride p-type layer to form a tunnel junction light emitting diode. A surface of the III-nitride tunnel junction n-type layer is done under illumination during an initial period and a remainder of the formation is completed absent illumination. The UV light has photon energy higher than the III-nitride p-type layer's band gap energy. The UV illumination inhibits formation of Mg—H complexes within the III-nitride p-type layer resulting from hydrogen present in a deposition chamber.

Abstract: A photocathode can include a body fabricated of a wide bandgap semiconductor material, a metal layer, and an alkali halide photocathode emitter. The body may have a thickness of less than 100 nm and the alkali halide photocathode may have a thickness less than 10 nm. The photocathode can be illuminated with a dual wavelength scheme.

Abstract: Disclosed herein is a semiconductor device. The semiconductor device includes a substrate, a first conductive type semiconductor layer disposed over the substrate, an active layer disposed over the first conductive type semiconductor layer, and a second conductive type semiconductor layer disposed over the active layer. The first conductive type semiconductor layer includes a first layer, a second layer and a third layer having different composition ratios of indium (In). The first semiconductor layer is disposed close to the active layer. The second semiconductor layer is disposed under the first semiconductor layer. The third semiconductor layer is disposed under the second semiconductor layer. In content is reduced from the active layer to the third semiconductor layer, and In content of the third semiconductor layer may be 5% or more to 10% or less of that of the active layer.

Abstract: A backlight module and liquid crystal display device are disclosed. The backlight module includes: at least one first light-emitting unit having a first blue light-emitting chip; at least one second light-emitting unit having a second blue light-emitting chip, wherein, an emission peak wavelength of the second blue light-emitting chip is greater than an emission peak wavelength of the first blue light-emitting chip; and a control circuit used for dynamic adjusting a brightness of the first light-emitting unit and the second light-emitting unit according to the blue saturation. The present invention can dynamically adjust the output amount of the blue light according to the blue saturation so that the present invention can selectively decrease the blue light when maintaining the display brightness and chroma.

Abstract: Provided is an epitaxial substrate for semiconductor elements which suppresses an occurrence of current collapse. The epitaxial substrate for the semiconductor elements includes: a semi-insulating free-standing substrate formed of GaN being doped with Zn; a buffer layer being adjacent to the free-standing substrate; a channel layer being adjacent to the buffer layer; and a barrier layer being provided on an opposite side of the buffer layer with the channel layer therebetween, wherein the buffer layer is a diffusion suppressing layer formed of Al-doped GaN and suppresses diffusion of Zn from the free-standing substrate into the channel layer.

Abstract: According to an aspect, an organic light-emitting device includes: a first electrode; a second electrode facing the first electrode; and an emission layer disposed between the first electrode and the second electrode and including a host and a dopant, wherein the host is an exciplex host, which is a combination of a hole transporting host and an electron transporting host which form an exciplex, or a delayed fluorescent organic compound, and the dopant includes both a phosphorescent dopant and a fluorescent dopant.

Abstract: An invisible-light light-emitting diode includes an N-type ohmic contact semiconductor layer, an N-type current spreading layer, an N—GaAs visible-light absorption layer, an N-type cladding layer, a light-emitting layer, a P-type cladding layer and a P-type ohmic contact semiconductor layer. In the invisible-light light-emitting diode, the absorption layer is GaAs, which can effectively remove all visible light when current density is >1 A/mm2, and essentially all visible light when current density is below 3 A/mm2. This effectively solves the red dot effect of invisible-light light-emitting diodes.

Abstract: Provided is a semiconductor multilayer film reflecting mirror formed by alternately repeating a first nitride film containing In (indium) and a second nitride film not containing In. The reflecting mirror includes an inter-film transition layer between the first and second nitride films, the composition of which is varied from the composition of the first nitride film to the composition of the second nitride film. The inter-film transition layer has a first transition layer formed on the first nitride film and containing In and Al (aluminum), and a second transition layer formed on the first transition layer and containing Al but not containing In. In the first transition layer, the percentages of In and Al are decreased from the first nitride film to the second transition layer, and the percentage of In in the first transition layer starts to decrease at a same or closer position to the first nitride film than the percentage of Al.

Abstract: The invention describes a device for emitting or detecting electromagnetic radiation. The device has a first and a second electrode which are connected to each other via an electrically conductive nanostructure. The electrically conductive nanostructure is configured to receive electrons and holes from the first and second electrode or transport same to the first and second electrode. In addition, the device has a radiation molecule arranged at a circumferential surface of the electrically conductive nanostructure. The radiation molecule is configured to absorb electrons and holes or electromagnetic radiation and emit the electromagnetic radiation with recombination of electrons absorbed and holes absorbed, or emit electrons and holes based on the electromagnetic radiation absorbed.

Abstract: A semiconductor chip includes a semiconductor body with a semiconductor layer sequence. An active region intended for generating radiation is arranged between an n-conductive multilayer structure and a p-conductive semiconductor layer. A doping profile is formed in the n-conductive multilayer structure which includes at least one doping peak.

Abstract: There is herein described light generating electronic components with improved light extraction and a method of manufacturing said electronic components. More particularly, there is described LEDs having improved light extraction and a method of manufacturing said LEDs.

Abstract: Metal contact openings are etched in the barrier layer of a group III-N HEMT with a first gas combination that etches down into the barrier layer, and a second gas combination that etches further down into the barrier layer to a depth that lies above the top surface of a channel layer that touches and lies below the barrier layer.

Abstract: A light-emitting diode includes semiconductor layers and electrodes. A first type semiconductor layer includes first and second low resistance portions and a high resistance portion therebetween. The high resistance portion encloses the first low resistance portion and is configured to confine charge carriers substantially within the first low resistance portion. A resistivity of the first type semiconductor layer increases from the first low resistance portion toward the high resistance portion and decreases from the high resistance portion toward the second low resistance portion. A first electrode is electrically connected to the first low resistance portion and substantially no current flows between the first electrode and the second low resistance portion. A portion of the first type semiconductor layer is between the first electrode and a second type semiconductor layer. A second electrode is electrically connected to the second type semiconductor layer.

Abstract: The present invention provides an epitaxial substrate for field effect transistor. In the epitaxial substrate for field effect transistor, a nitride-based Group III-V semiconductor epitaxial crystal containing Ga is interposed between the ground layer and the operating layer, and the nitride-based Group III-V semiconductor epitaxial crystal includes the following (i), (ii) and (iii). (i) a first buffer layer containing Ga or Al and containing a high resistivity crystal layer having added thereto compensation impurity element present in the same period as Ga in the periodic table and having small atomic number; (ii) a second buffer layer containing Ga or Al, laminated on the operating layer side of the first buffer layer; and (iii) a high purity epitaxial crystal layer containing acceptor impurities in a slight amount such that non-addition or depletion state can be maintained, provided between the high resistivity layer and the operating layer.

Abstract: Exemplary embodiments provide a UV light emitting diode and a method of fabricating the same. The method of fabricating a UV light emitting diode includes growing a first n-type semiconductor layer including AlGaN, wherein growth of the first n-type semiconductor layer includes changing a growth pressure within a growth chamber and changing a flow rate of an n-type dopant source introduced into the growth chamber. A pressure change during growth of the first n-type semiconductor layer includes at least one cycle of a pressure increasing period and a pressure decreasing period over time, and change in flow rate of the n-type dopant source includes increasing the flow rate of the n-type dopant source in the form of at least one pulse. The UV light emitting diode fabricated by the method has excellent crystallinity.

Abstract: The present invention provides a method for fabricating an InGaP epitaxial layer by metal organic chemical vapor deposition (MOCVD). The method comprises: placing a silicon substrate in a reaction chamber; arranging the reaction chamber to have a first chamber temperature, and growing a first GaP layer with a first thickness on the Si substrate at the first chamber temperature; arranging the reaction chamber to have a second chamber temperature, and growing a second GaP layer with a second thickness on the first GaP layer at the second chamber temperature; arranging the reaction chamber to have a third chamber temperature for a first time interval, and then arranging the reaction chamber to have a fourth chamber temperature for a second time interval; and growing a multi-layered InGaP layer on the second GaP layer.

Abstract: A method for producing a MEMS device comprises forming a semiconductor layer stack, the semiconductor layer stack comprising at least a first monocrystalline semiconductor layer, a second monocrystalline semiconductor layer and a third monocrystalline semiconductor layer, the second monocrystalline semiconductor layer formed between the first and third monocrystalline semiconductor layers. A semiconductor material of the second monocrystalline semiconductor layer is different from semiconductor materials of the first and third monocrystalline semiconductor layers. After forming the semiconductor layer stack, at least a portion of each of the first and third monocrystalline semiconductor layers is concurrently etched.

Abstract: A method of thinning a bulk aluminum nitride substrate includes providing a bulk aluminum nitride (AlN) substrate with at least one epitaxially grown group-III-nitride layer on a first side of the substrate, applying a slurry having a high pH to a second side of the substrate opposite the first side, chemical mechanically polishing the second side of the substrate using the slurry to remove at least a portion of the substrate, resulting in a thinned layer with a thickness less than 50 microns, and bonding the epitaxial layer to a non-native substrate. A device has at least one active zone in a layer of epitaxial Group-III-nitride material, the epitaxial Group-III-nitride layer having a defect density of less than or equal to 108/cm2.

Abstract: A controller adapts the read voltage thresholds of a memory unit in a non-volatile memory. In one embodiment, the controller determines, based on statistics for a memory unit of the non-volatile memory, an operating state of the memory unit from among a plurality of possible operating states and adapts at least one read voltage threshold for a memory cell in the memory unit based on the determined operating state.

Abstract: An organic electroluminescent device includes at least two light-emissive units provided between a cathode electrode and an anode electrode opposed to the cathode electrode, each of the light-emissive units including at least one light-emissive layer. The light-emissive units are partitioned from each other by at least one charge generation layer, the charge generation layer being an electrically insulating layer having a resistivity of not less than 1.0×102 ?cm.

Abstract: In various embodiments, light-emitting devices incorporate graded layers with compositional offsets at one or both end points of the graded layer to promote formation of two-dimensional carrier gases and polarization doping, thereby enhancing device performance.

Abstract: In various embodiments, light-emitting devices incorporate graded layers with compositional offsets at one or both end points of the graded layer to promote formation of two-dimensional carrier gases and polarization doping, thereby enhancing device performance.

Abstract: In an example, the present invention provides a gallium and nitrogen containing laser diode device. The device has a gallium and nitrogen containing substrate material comprising a surface region, which is configured on either a ({10-10}) crystal orientation or a {10-10} crystal orientation configured with an offcut at an angle toward or away from the [0001] direction. The device also has a GaN region formed overlying the surface region, an active region formed overlying the surface region, and a gettering region comprising a magnesium species overlying the surface region. The device has a p-type cladding region comprising an (InAl)GaN material doped with a plurality of magnesium species formed overlying the active region.

Abstract: LED structures are disclosed to reduce non-radiative sidewall recombination along sidewalls of vertical LEDs including p-n diode sidewalls that span a top current spreading layer, bottom current spreading layer, and active layer between the top current spreading layer and bottom current spreading layer.

Abstract: A semiconductor optical device includes: a first conductive type semiconductor layer; an active layer; a second conductive type semiconductor layer including a ridge portion; a pair of first grooves, formed on bottom surfaces of both sides of the ridge portion and dividing the active layer; an optical functioning part including the first and second conductive type semiconductor layers, converting a state of light, and having a height higher than a height of the bottom surface of the ridge portion; and a second groove, at least a part thereof being formed on the optical functioning part, an end portion thereof being connected to the first groove, the second conductive type semiconductor layer being divided, and the maximum height of an inner wall surface thereof being higher than the maximum height of an inner wall surface of the first groove.

Abstract: A barrier film and a method of manufacturing the barrier film are provided. The method includes performing high-pressure thermal treatment under certain conditions on an oxide thin film deposited by sputtering deposition or atomic layer deposition (ALD) to manufacture a barrier film with improved moisture resistance. According to the method, moisture resistance of the barrier film can be improved at a low process temperature by using both thermal energy and pressure energy. The barrier film provided herein can be useful as a barrier film for solar cells.

Abstract: Embodiments of the present disclosure are directed to infrared detector devices incorporating a tunneling structure. In one embodiment, an infrared detector device includes a first contact layer, an absorber layer adjacent to the first contact layer, and a tunneling structure including a barrier layer adjacent to the absorber layer and a second contact layer adjacent to the barrier layer. The barrier layer has a tailored valence band offset such that a valence band offset of the barrier layer at the interface between the absorber layer and the barrier layer is substantially aligned with the valence band offset of the absorber layer, and the valence band offset of the barrier layer at the interface between the barrier layer and the second contact layer is above a conduction band offset of the second contact layer.

Abstract: The embodiments of the present invention provide an organic electroluminescent device, a manufacturing method thereof and an electronic equipment. The organic electroluminescent device comprises: an anode layer, a hole transport layer, a first light emitting layer, a second light emitting layer, an electron transport layer, and a cathode layer stacked in sequence; wherein the first light emitting layer and the second light emitting layer comprise a same substrate material; the first light emitting layer and/or the second light emitting layer are doped such that a hole mobility of the first light emitting layer is equal to an electron mobility of the second light emitting layer. In the embodiments of the present invention, two light emitting layers with the same substrate material are applied, which can realize a balanced injection for electrons and holes, thereby improving the efficiency and lifetime of the organic electroluminescent device.