31results about How to "Reduced polarizing electric field" patented technology

The invention discloses a GaN-based light-emitting diode epitaxial wafer production method and a produced epitaxial wafer, and belongs to the field of semiconductor light-emitting diodes. The method includes growing a buffer layer, an n-type GaN layer, a stress regulation layer, a multiple quantum well layer, a p-type GaN layer and a p-type ohmic contact layer on a substrate sequentially. The stress regulation layer is of a multi-period structure. A growth method of each period of the multi-period structure includes growing a stress regulation InGaN sub layer at a first growth temperature, supplying hydrogen into a reaction chamber at a second growth temperature after the stress regulation InGaN sub layer finishes growing, and etching the surface of the stress regulation InGaN sub layer, wherein the second growth temperature is different from the first growth temperature. The GaN-based light-emitting diode epitaxial wafer production method and the produced epitaxial wafer have the advantages that through treatment of the stress regulation InGaN sub layer, a smooth contact surface is formed between the stress regulation InGaN sub layer and a stress regulation GaN sub layer, and accordingly, continuous extension of defects is prevented.

The invention discloses an LED epitaxial structure based on a graphene substrate, a growing method and an LED. The graphene substrate comprises a substrate and a graphene layer positioned on the surface of one side of the substrate. The LED epitaxial structure comprises a buffer layer grown on the graphene substrate and an N-type GaN layer, an active layer and a P-type GaN layer which are grown onthe buffer layer in an overlapped manner in sequence, wherein the buffer layer comprises buffer sub-layers grown on the surface of the side, away from the substrate, of the graphene layer; the buffersub-layers are AlN buffer sub-layers, GaN buffer sub-layers, InGaN buffer sub-layers or AlGaInN buffer sub-layers. Through the technical scheme provided by the invention, the buffer layer of the LEDepitaxial structure is grown on the graphene substrate, the lattice mismatch between the LED epitaxial structure and the graphene substrate is reduced, the stress between the graphene substrate and the LED epitaxial structure is reduced, and then the LED epitaxial structure with high crystalline quality can be prepared, so that a polarization electric field is reduced effectively, the bending of an energy band is reduced, and the composite efficiency of electrons and holes is improved.

An ultraviolet light-emitting diode (LED) epitaxial structure, comprising: a substrate (1); an undoped buffer layer (2), an N-type AlGaN layer (3), a multi-quantum well structure (4), a superlattice structure (5), an electron blocking layer (6), a P-type AlGaN layer (7), and a P-type GaN layer (8), which are sequentially grown on the substrate (1); the superlattice structure (5) comprises at least one first AlGaN layer and at least one second AlGaN layer, the first AlGaN layer and the second AlGaN layer being alternatingly stacked. Since the superlattice structure (5) is added between the multi-quantum well and the electron blocking layer (6), the superlattice structure (5) may effectively alleviate strain between the last quantum barrier of an active region and the electron blocking layer (6), suppress electron leakage, and increase hole injection rate, thereby improving the optical output power and internal quantum efficiency of an ultraviolet LED, causing the ultraviolet LED to present better light-emitting performance.

A green light GaN-based LED epitaxial structure relates to the technical field of LED epitaxial growth. The green light GaN-based LED epitaxial structure comprises a GaN core layer, a non-doped GaN layer, an n-type GaN layer, an InGaN / GaN multiple quantum well active layer and a p-type GaN layer which are sequentially grown on a stone substrate and is characterized in the InGaN / GaN multiple quantum well active layer comprises a GaN barrier layer, a first component gradient Gradedwell buffer layer, an InGaN quantum well layer, a second component gradient Gradedwell buffer layer and a variable temperature GaN transition layer. A 10mil*12mil 520-nanometer green light chip is made by using nitride epitaxial pieces grown by the method and a standard chip process, brightness of the green light chip under 20mA raises from 600mcd to 850mcd, after encapsulation, brightness of the same raises from 4.91m to 6.21m, external quantum efficiency raises from 21% to 30%, and a high-brightness green light GaN-based LED is achieved.

The invention discloses a light emitting diode with a nitrogen polar surface n-type electron blocking layer, which comprises a substrate, a nitrogen polar nitride layer, a polarity inversion nitride layer, and an n-type nitride ohmic contact layer in order from bottom to top , n-type nitrogen polar surface electron blocking layer, non-doped superlattice structure layer, multiple quantum well active layer, p-type nitride ohmic contact layer. An n-type electrode and a p-type electrode are respectively provided on the n-type nitride ohmic contact layer and the p-type nitride ohmic contact layer. The n-type electron blocking layer with nitrogen polar face provided by the present invention can spatially limit the number of electrons entering the active region, and because the traditional p-type doped electron blocking layer is removed, it can increase the amount of electrons entering the active region. The injection rate of holes keeps the number of holes and electrons injected into the active region at a balanced level, which can improve the probability of electrons and holes in the active region radiating recombination light, thereby improving the performance of the light-emitting diode.

The invention discloses a preparation method of an epitaxial structure of a gallium nitride based laser device, comprising the following steps of: (a) epitaxially growing one GaN buffer layer on a substrate; (b) epitaxially growing an n-type light limiting layer on the buffer layer; (c) growing a lower waveguide layer; (d) epitaxially growing an InaGa1-aN / GaN multi-quantum well as an active region; after growing the last InaGa1-aN / GaN multi-quantum well, replacing the last GaN barrier layer by an AlGaN layer, wherein the AlGaN layer is an AlxGa1-xN which is 1-50 nm in thickness and has gradually-changed Al components or is composed of at least two layers of AlyGa1-yN layers with gradually-increased Al components; (e) epitaxially growing one p-type AlzGa1-zN electron blocking layer, wherein in the steps (d) and (e), x is more than or equal to 0 and is less than or equal to y, y is more than or equal to x and is less than or equal to z, and z is more than or equal to y and is less than or equal to 1; (f) growing an upper waveguide layer; (g) growing a p-type light limiting layer; and (h) growing an ohm contact layer. According to the preparation method provided by the invention, the problem of electron accumulation of the uppermost GaN barrier layer and an AlGaN electron blocking layer is solved, and the performance of the laser device is effectively improved.

The invention relates to a process of growing a nucleating layer on the surface of a patterned substrate at a low temperature to form an uneven surface. The invention overcomes the problem that in a conventional LED (Light-Emitting Diode) device structure, an active layer has a superstrong depolarization field, and thus, an energy band of a quantum well is inclined, an electron hole wave function is separated in space and the radiative recombination efficiency is reduced, so that the internal quantum efficiency of a LED is reduced. The invention also provides an epitaxial wafer structure of a gallium nitride-based LED and a preparation method of the epitaxial wafer structure, wherein the epitaxial wafer structure has high crystalline quality and a nonplanar active layer structure is implemented on a weak polarity surface of the epitaxial wafer structure. Therefore, the internal quantum efficiency of the LED is improved.

The invention discloses a GaN-based semiconductor device with a composite gradual-change quantum barrier structure and a preparation method of the semiconductor device. The device comprises a multi-quantum well structure, the multi-quantum well structure comprises InGaN layers which grown alternatively, the average In content in the different quantum barrier layers in the multi-quantum well structure is reduced gradually from the P type side to the N type side, and the In content in at least one quantum barrier layer is increased gradually from the P type side to the N type side. Due to use of the composite gradual-change quantum barrier structure in the device, the polarized electric field in the quantum well region can be reduced, the electron-hole composite efficiency is increased, hole transportation is improved, distribution non-uniformity of the holes among wells is reduced, leakage of electrons is reduced, the light emitting efficiency of LED devices and the like can be improved obviously, the problem of decrease of the light emitting efficiency is inhibited substantially, preparation technology is simple and controllable, and convenience is provided for large-scale enforcement.

The invention relates to the field of a semiconductor, and discloses an LED epitaxial structure. The LED epitaxial structure comprises a substrate, a nucleating layer, a non-doped GaN layer, an n type GaN layer and a porous SiN<x> layer on the n type GaN layer, and also comprises an n type GaN hexagonal-pyramid array formed in the holes of the porous SiN<x> layer, and quantum dots on the peak of the hexagonal pyramid, quantum lines on the six ridges and a multi-quantum-well layer on six semi-polar (10-11) crystal surfaces, and a p type GaN filling layer at the tail part; and the GaN hexagonal pyramid and the quantum dots / lines / well layer at different positions thereon form the three-dimensional core-shell structure. The structure is large in light emitting area and high in light extracting efficiency; in addition, due to influences of different In contents and polarization effects and other factors, the light emitting wavelengths of the quantum dots / lines / well structures are also different; through reasonable control, white light emission can be realized; in the preparation method of the GaN hexagonal pyramid array, substrate patterning is not needed, so that the technological process is simple; and meanwhile, the grown GaN crystals are high in quality, so that the luminous efficiency of the LED can be improved effectively.

The disclosure provides an epitaxial wafer of a light emitting diode and a preparation method thereof, which belong to the technical field of optoelectronic manufacturing. The epitaxial wafer includes a substrate, an AlN buffer layer, a three-dimensional nucleation layer, a u-type GaN layer, an n-type GaN layer, a multi-quantum well layer, a low-temperature p-type layer, an electron blocking layer, and a high-temperature p-type layer. The multi-quantum well layer includes Multiple In x Ga 1‑x N quantum well layer and multiple GaN quantum barrier layers, and the In x Ga 1‑x Composite structure between N quantum well layer and GaN quantum barrier layer, the composite structure includes n-In y Ga 1‑y N layer and SiN layer. n‑In y Ga 1‑y The Si atoms in the N layer can fill the defect vacancies in the InGaN material. The InGaN material with a lower In composition is conducive to weakening the polarization electric field and improving the energy band tilt. The SiN layer is conducive to the uniformity of carriers in the multi-quantum well layer. Diffusion, improve the carrier localization effect, and improve the luminous efficiency of LED.