32results about How to "Improve composite luminous efficiency" patented technology

The invention provides a near-ultraviolet LED lamp with a novel electron blocking layer, and a preparation method thereof. A near-ultraviolet LED epitaxial wafer structure comprises a graphical sapphire substrate, a low-temperature GaN nucleating layer, a high-temperature non-doped GaN buffer layer, an n-type GaN layer, an InGaN/AlGaN multiple-quantum well active layer, a p-type AlGaN/InGaN superlattice electron blocking layer, a low-temperature lightly-doped p-type AlInGaN hole expansion layer, a high-temperature p-type GaN layer and a p-type InGaN contact layer. The electron blocking layer adopts a p-type Al<y1>Ga<1 y1>N/In<x1>Ga<1 x1>N superlattice structure. Along with the increase of the number of superlattice periods, the InGaN thickness is reduced step by step, the Mg doping concentration is increased step by step and the hole concentration is increased. By the invention, the hole injection efficiency is effectively improved and the electron hole recombination luminous efficiency is enhanced, so the near-ultraviolet LED luminous efficiency is increased.

The invention provides a method for preparing a p-type AlGaN/AlInGaN electron blocking layer near ultraviolet LED with doping density and Al component in stepwise change. In an LED epitaxial structure, an electron blocking layer adopts a p-type Aly1Ga1-y1N/AlyInx1Ga1-x1N superlattice structure, and the Al component is reduced from 0.2 to 0.05 stepwisely with the increase of superlattice cycle number; Mg doping density increases stepwisely with the increase of superlattice cycle number, and corresponding hole concentration increases from 0.5*10<17> cm<3> to 2* 10<17> cm<3>; the thickness range of the AlGaN barrier layer is 2-5 nm; and the thickness of the GaN well layer is 2 nm-5 nm. Through the design of the novel ultraviolet LED electronic blocking layer structure, hole injection efficiency can be improved effectively, and electron-hole recombination luminescence efficiency is improved, and thus near ultraviolet LED luminescence efficiency is improved.

The invention discloses a UV light emitting diode with a compound electronic barrier layer structure. The light emitting diode, successively from the bottom to the top, includes a substrate (101), a low-temperature AlN nucleation layer (102), a high-temperature AlN buffer layer (103), an n type AlGaN layer (104), an Al<x>Ga<1-x>N/Al<y>Ga<1-y>N multi-quantum well active region (105), and a p-AlsIntGa1-s-tN/p-AlzGa1-zN compound electronic barrier layer (106) consisting of a p-Al<s>In<t>Ga<1-s-t> layer (106) and a p-Al<z>Ga<1-z>N layer. The diode provided can solve the problem that a conventional electronic barrier layer structure generates a parasitic electronic inversion layer between the last quantum well barrier and an electronic barrier layer.

The invention discloses a light-emitting diode epitaxial wafer and a manufacturing method thereof and belongs to the semiconductor optoelectronic technical field. The light-emitting diode epitaxial wafer includes a sapphire substrate as well as a buffer layer, an undoped GaN layer, an N type GaN layer, a current spreading layer, a multi-quantum well layer and a P type GaN layer which are stacked on the sapphire substrate sequentially; the current spreading layer includes a first sub layer and a second sub layer which are grown alternately; the first sub layer is made of a variable resistance material; the second sub layer is made of N type doped GaN; and the doping concentration of the second sub layer is smaller than that of the N type GaN layer. According to the light-emitting diode epitaxial wafer and the manufacturing method thereof of the invention, the current spreading layer includes the first sub layer and the second sub layer which are grown alternately; the difference of lattice constants of the first sub layer and the second sub layer enables a polarization effect; charge distribution in the current spreading layer is nonuniform, so that an electric field can be formed, and current can be spread under the action of the electric field; and recombined luminescent electrons injected into the multi-quantum well layer are increased, and therefore, the efficiency of recombination luminescence can be improved.

The invention discloses an epitaxial wafer for a light-emitting diode and a manufacturing method for the epitaxial wafer, and belongs to the technical field of semiconductors. The epitaxial wafer comprises a substrate, a buffering layer, a non-doped gallium nitride layer, an N-type gallium nitride layer, a light-emitting layer and a P-type gallium nitride layer, wherein the buffering layer, the non-doped gallium nitride layer, the N-type gallium nitride layer, the light-emitting layer and the P-type gallium nitride layer are sequentially stacked on the substrate. The light-emitting layer comprises a plurality of quantum well layers and a plurality of quantum barrier layers. The plurality of quantum well layers and the plurality of quantum barrier layers are alternately stacked together. The quantum barrier layers are gallium nitride layers, and at least three quantum well layers, which are the nearest to the N-type gallium nitride layer, of the plurality of quantum well layers are the first quantum well layers. The plurality of quantum well layers, except the first quantum well layers, are the second quantum well layers. The first quantum well layers are non-doped indium gallium nitride layers, and the second quantum well layers comprise P-type doped indium gallium nitride layers. According to the invention, the number of holes in the quantum well layers is increased, and the hole and electron recombination illiumination efficiency is improved.

The invention discloses a green light emitting diode epitaxial wafer and a preparation method thereof and belongs to the technical field of a semiconductor. The green light emitting diode epitaxial wafer includes a substrate, an N-type semiconductor layer, an active layer and a P-type semiconductor layer, wherein the N-type semiconductor layer, the active layer and the P type semiconductor layer are sequentially laminated on the substrate, the active layer includes multiple quantum wells and multiple quantum barriers, the multiple quantum wells and the multiple quantum barriers are arranged inan alternate lamination mode, the material of the quantum wells employs non-doped MoS2, and the material of the quantum barriers employs non-doped InxAl1-xN, and the x is greater than 0 and smaller than 0.3. The epitaxial wafer is advantaged in that the non-doped MoS2 is utilized as the material of the quantum wells, the non-doped InxAl1-xN is utilized as the material of the quantum barriers, 0<x<0.3, lattice matching between the InxAl1-xN and the MoS2 is better, and the polarization effect of LEDs can be effectively alleviated.

The invention discloses a light-emitting diode epitaxial wafer and a manufacture method thereof and belongs to the technical field of semiconductors. The light-emitting diode epitaxial wafer comprisesan electronic barrier layer that includes superlattice structure of N cycles; the superlattice structure of each cycle includes an InxGa1-xN layer and an AlyG1-yN layer, wherein the InxGa1-xN layer is formed by growth at 900-950 DEG C; lattice quality of a multi-quantum well layer can be improved, composite light-emitting efficiency of electrons and holes in the multi-quantum well layer can be improved. In addition, the presence of In brings down activation energy of Mg and increases hole concentration of a P-type layer. Each AlyG1-yN layer is formed by growth at 950-980 DEG C, barrier heightof the AlyG1-yN layer is increased, and electrons are avoided overflowing to the P-type layer; the content of Al gradually decreases or increases, so that electrons can be avoided overflowing to theP-type layer at the premise of reducing the blocking action of holes, and light-emitting efficiency of a diode is improved.

The invention provides an epitaxial wafer of an AlGaN-based deep ultraviolet light emitting diode and a preparation method of the epitaxial wafer, and belongs to the technical field of photoelectron manufacturing. The epitaxial wafer comprises a substrate, and an AlN layer, an n-type AlGaN layer, a multi-quantum well layer, a p-type AlGaN layer and a p-type ohmic contact layer which are sequentially formed on the substrate; the p-type ohmic contact layer comprises a plurality of p-type GaN layers and a plurality of hexagonal boron nitride layers which are sequentially and alternately stacked, and the doping concentration of each p-type GaN layer is increased layer by layer along the growth direction of the epitaxial wafer. According to the embodiment of the invention, the conductivity of the p-type layer can be improved, and the problem of lattice mismatching between the AlGaN layer and the p-type GaN layer is relieved, so that the crystal quality of the p-type layer is improved.

The present invention provides a QLED device comprising a bottom electrode, a bipolar Auger energy multiplying structure and a top electrode, wherein the bottom electrode, a bipolar Auger energy multiplying structure and the top electrode are sequentially laminated on a substrate, and the bipolar Auger energy multiplying structure comprises a hole transport layer, a quantum dot light-emitting layer and an electron transport layer, and the hole transport layer, the quantum dot light-emitting layer and the electron transport layer are sequentially bonded. The electron transport layer is made ofan n-type nano material, and the hole transport layer is made of a p-type nano material.

The invention discloses a heteroanthracene derivative and a preparation method and application thereof, and an organic electroluminescent device. According to the heteroanthracene derivative, at leastone site selected from site 2, site 3 and site 7 of a heteroanthracene group is substituted by a hole transport type group, and the heteroanthracene derivative has a parent nucleus structure of heteroanthracene, so a D-A type compound or a hole transport type compound with a star-shaped spatial configuration is formed; the substitution of multi-site aromatic groups and the star-shaped configuration enable the derivative to have better stability and a balanced electron/hole transport rate in device preparation and application; and as a light-emitting host material or hole transport material ofan organic light-emitting device, the derivative has higher quantum recombination efficiency, can effectively solve the problems of electron/hole imbalance and easy crystallization in a device, emitspurer light color, and has more remarkable advantages than similar compounds and compounds in the prior art in the aspects of starting voltage, current efficiency, service life and thermal stability.