55results about How to "Reduce Mismatch Problems" patented technology

The invention discloses a GaN-based LED epitaxy structure and a preparation method thereof. The GaN-based LED epitaxy structure sequentially comprises a substrate, a GaN nucleating layer, a superlattice buffer layer, a non-doped GaN layer, an N type GaN layer, a multi-quantum-well luminescent layer, and a P type GaN layer, wherein the superlattice buffer layer adopts a superlattice structure which is prepared by alternately stacking a plurality of pairs of AlGaN buffer layers, AlN buffer layers and GaN buffer layers. The GaN-based LED epitaxy structure disclosed by the invention can relieve the lattice mismatch problem due to mismatch between the sapphire substrate and the GaN lattice, greatly reduces the warping of the epitaxial wafer during the whole high-temperature growth process, promotes the wavelength centrality and the yield of the epitaxial wafer, meanwhile effectively increases the GaN lattice quality, reduces the lattice dislocation density, and enables the optical-electrical characteristics of the device to be more stable.

The invention discloses a ZnO-based nanorod / quantum well composite ultraviolet light-emitting diode and a preparation method thereof. The light-emitting diode comprises a substrate. The substrate is provided with an n-type ZnO thin film layer, a ZnO nanorod array, a ZnO / Zn1-xMgxO quantum well active layer, a p-type NiO thin film layer and a first electrode from the bottom up in sequence. A second electrode and the ZnO nanorod array are arranged on the n-type ZnO thin film layer in parallel; and the ZnO / Zn1-xMgxO quantum well active layer covers the ZnO nanorod array, 0.1<=x<=0.3. The light-emitting diode electroluminescent peak wavelength is around 374 nm, and full width at half maximum of the photoluminescence peak is around 17 nm; the light-emitting diode structure can give full play to the advantages of direct broadband gap and high exciton binding energy of the ZnO material and the like, so that polarization effect is reduced effectively, material and interface quality can be improved, effective area of the active layer is increased, light extraction efficiency is improved and spectrum monochromaticity is improved; and besides, low-temperature preparation can be realized, cost is low and industrialization can be realized easily.

The invention discloses a light emitting diode epitaxial wafer and a preparation method thereof, and belongs to the field of light emitting diode manufacturing. A buffer layer comprises a first sub-layer and a second sub-layer, and the first sub-layer plays a role in transition. The second sub-layer stacked on the first sub-layer comprises second GaN layers and BGaN layers which are alternately stacked. On one hand, lattice mismatch is relieved, a good foundation is provided for growth of a subsequent epitaxial structure, and on the other hand, the BGaN layers can be inserted into or fill blank positions caused by dislocation due to the fact that the volume of B atoms is small, and defects existing in the buffer layer are reduced. Moreover, B atoms can play a certain role in positioning, so that dislocation is prevented from continuing moving into an n-type GaN layer and a multi-quantum well layer, and the crystal quality of the finally obtained light-emitting diode epitaxial wafer iseffectively improved.

The invention provides a method for preparing a high (110) oriented non-polar zinc oxide thin film on a Si-based substrate. The method comprises the steps of taking Si as a substrate, taking a ZnO target material as a zinc source and an oxygen source, taking Ar as working gas, taking O2 as reaction gas, adopting a magnetron sputtering method, controlling the vacuum degree below 8*10<-4>Pa, controlling the growth temperature at 100-400 DEG C and simultaneously introducing Ar and O2 in a certain proportion to prepare the thin film. The method comprises the steps of growing a (100) oriented LaNiO3 (LNO) buffer layer on the Si-based substrate and growing a high (110) oriented ZnO thin film on a (100) LNO / Si substrate. By adding the LNO buffer layer, the growth of the high (110) oriented non-polar ZnO thin film can be effectively realized, the band-edge emission in a photoluminescence spectrum is obviously enhanced, and a defect luminescence peak is obviously weakened.

The invention relates to a multilayer ceramic lining composite tube and its preparation method, is a composite steel tube taking intermetallic compound and titanium compound as ceramic lining, which belongs to the technique field of gradient composite material. The invention conqueres the disadvantage of bad mechanical combine construction and mechanics property of ceramic coating and metal coating, when ceramic lining composite tube is prepared with self-spread centrifugal burning method. The invention is characterized in that filling mixture of pulverous reaction raw material in the steel tube and fixing it on the rotary mechanism, When rotate speed is at 1500-2000rpm, igniting reaction raw material with ignition device and making them form high-heat self-spread reaction; the products synthesized form layered lining layer on the inwall of the steel tube according to different density; the construction of the lining layer synthesized is ordinally steel tube, intermetallic compound, titanium compound ceramic, alumina ceramic along radial. The bonding strength, mechanics property, abrasion resistance and corrosion resistance had enhanced remarkably in this invention.

The application discloses an LED epitaxial growth method suitable for a small-spacing display screen. The method comprises the following steps: processing a substrate; growing a low-temperature bufferlayer GaN; growing an undoped GaN layer; growing a Si-doped N type GaN layer; growing a multi-quantum well layer; growing an AlGaN electronic barrier layer; growing a Mg-doped P type GaN layer; and then performing cooling. The growth of the multi-quantum well layer sequentially comprises the steps: growing an InGaN well layer; growing an H2 atmosphere InGaN: Si layer; growing an N2 atmosphere InGaN: Mg layer; growing an H2 and N2 mixed atmosphere InGaN: Mg / Si layer; growing an InGaN protective layer; and growing a GaN barrier layer. The method provided by the invention solves the problem thatthe blue shift amount of the light emitting wavelength of the LED is large in the existing LED epitaxial growth, and the light emitting efficiency of the LED is improved, the working voltage is reduced and the anti-static capability is enhanced.

The invention discloses a nitride epitaxial layer preparation method and a semiconductor epitaxial wafer thereof. The method comprises the following steps: providing a substrate; a buffer layer is grown on the substrate, the buffer layer comprises a nitride buffer layer and an oxygen-containing buffer layer, and the nitride buffer layer and the oxygen-containing buffer layer are grown by alternately switching an MO source and an oxygen-containing MO source in a periodic cycle mode to serve as precursor materials; and growing a nitride epitaxial layer on the buffer layer. The oxygen-containing buffer layer is grown through the oxygen-containing MO source process, on one hand, the in-situ growth oxygen-containing buffer layer has good lattice mismatch relaxation, relieves lattice adaptation and releases the stress of the substrate and the epitaxial layer, and a high-quality gallium nitride epitaxial layer with low dislocation density can be obtained; the distribution uniformity and nucleation density of oxygen-containing buffer crystal grains are improved, and a high-quality nitride epitaxial layer is obtained; on the other hand, the technological process is simple, pollution risks in the substrate and epitaxial layer transfer process are reduced, repeatability is good, and large-scale production is facilitated.

The invention discloses a ZnO-based nanorod / quantum well composite ultraviolet light-emitting diode and a preparation method thereof. The light-emitting diode comprises a substrate. The substrate is provided with an n-type ZnO thin film layer, a ZnO nanorod array, a ZnO / Zn1-xMgxO quantum well active layer, a p-type NiO thin film layer and a first electrode from the bottom up in sequence. A second electrode and the ZnO nanorod array are arranged on the n-type ZnO thin film layer in parallel; and the ZnO / Zn1-xMgxO quantum well active layer covers the ZnO nanorod array, 0.1<=x<=0.3. The light-emitting diode electroluminescent peak wavelength is around 374 nm, and full width at half maximum of the photoluminescence peak is around 17 nm; the light-emitting diode structure can give full play to the advantages of direct broadband gap and high exciton binding energy of the ZnO material and the like, so that polarization effect is reduced effectively, material and interface quality can be improved, effective area of the active layer is increased, light extraction efficiency is improved and spectrum monochromaticity is improved; and besides, low-temperature preparation can be realized, cost is low and industrialization can be realized easily.

The invention discloses a light-emitting diode epitaxial wafer and a preparation method thereof, belonging to the field of light-emitting diode production. The alternately stacked AlGaN sub-layers and the first GaN sub-layer can release certain stress during the growth process, and less dislocation defects will be accumulated in the first composite layer. The buffer layer also includes a second composite layer stacked on the first composite layer, and the structure of the second composite layer can be alternately stacked second GaN sublayers and MgN sublayers, alternately stacked second GaN sublayers and BN sublayers . Mg atoms and B atoms in the BN sublayer have small particle sizes, which can fill the vacancies generated by defects and dislocations in the crystal during growth, thereby reducing the formation of dislocations and defects, improving the crystal quality of the buffer layer, and finally obtaining The luminous efficiency of the light-emitting diode epitaxial wafer is also improved.

The invention relates to a W type antimony-based semiconductor laser with gradually varied Ga In proportion, which belongs to the technical field of semiconductor lasers. The existing InAs / GaInSb W type antimony-based semiconductor laser is difficult to realize luminescence at room temperature, and is less in output power of luminescence at low temperature (73K). The W type antimony-based semiconductor laser with gradually varied Ga In proportion sequentially comprises a GaSb substrate, a GaSb buffer layer, a P type GaSb contact layer, a P type quantum well, an intrinsic quantum well, an N type quantum well and an N type InAs contact layer from bottom to top, wherein the P type quantum well, the intrinsic quantum well and the N type quantum well respectively have a multi-period structure; the structure of each single-period quantum well in each multi-period structure is a sandwich structure that a GaInSb hole quantum well is clamped by double InAs electronic quantum wells; the outer layer is a pair of AlSb alloy limiting layers. The W type antimony-based semiconductor laser with gradually varied Ga In proportion is characterized in that the GaInSb hole quantum well is formed by 3 to 9 layers of Ga1-xInxSb layers, wherein x is equal to 0.05-0.35; the value of x of the Ga1-xInxSb layer in the middle is maximal; the Ga1-xInxSb layers on two sides are distributed in 1 to 4 levels from the middle to two sides; the values of x of two Ga1-xInxSb layers at the same level are the same, and the values of x of the Ga1-xInxSb layers from the middle to two sides are gradually reduced.

The invention discloses a light emitting diode epitaxial wafer and a growth method thereof, and belongs to the technical field of semiconductors. The epitaxial wafer comprises a substrate, an N-type limiting layer, an active layer, a P-type AlInP limiting layer, a transition layer and a P-type GaP window layer, which are stacked in sequence. The transition layer comprises (N+1) first sub-layers and N second sub-layers, which are alternately stacked; each first sub-layer is an AlGaInP layer; the content of the Al component in the (N+1) first sub-layers is gradually decreased in the direction from the P-type AlInP limiting layer to the P-type GaP window layer, and the content of the Ga component in the (N+1) first sub-layers is gradually increased in the direction from the P-type AlInP limiting layer to the P-type GaP window layer; each second sub-layer is a GaP layer, and the total thickness of the N second sub-layers is 1 / 200-1 / 20 of the total thickness of the (N+1) first sub-layers. The light-emitting efficiency of an LED can be improved.

The invention discloses a gallium nitride based light emitting diode and a preparation method therefor, and belongs to the technical field of the semiconductor. The gallium nitride based light emitting diode comprises a sapphire substrate, and a buffer layer, a non-doped GaN (gallium nitride) layer, a stress improvement layer, an N type GaN layer, an active layer, a P type electron barrier layer and a P type GaN layer which are laminated on the sapphire substrate in sequence, wherein the stress improvement layer is formed by elements of Al, Ga and N under the atmosphere of N2 and H2 at a volume ratio of 2:1 to 1:1; and the surface of the stress improvement layer is uneven. According to the gallium nitride based light emitting diode, the stress improvement layer which is formed by the elements of Al, Ga and N under the atmosphere of N2 and H2 at a volume ratio of 2:1 to 1:1 is laminated between the non-doped GaN layer and the N type GaN layer, so that the lattice mismatch between the sapphire and the GaN is relieved, and the crystal quality of the light emitting diode is improved.

The invention discloses a gallium nitride-based light emitting diode epitaxial wafer and a preparation method thereof and belongs to the technical field of a semiconductor. The gallium nitride-based light emitting diode epitaxial wafer includes a substrate, and a buffer layer, a quality improvement layer, an N-type semiconductor layer, an active layer and a P-type semiconductor layer which are sequentially stacked on the substrate, wherein the material of the substrate is sapphire, the material of the N-type semiconductor layer, the active layer and the P-type semiconductor layer is a galliumnitride-based material, the quality improvement layer includes a first sub layer and a second sub layer which are sequentially stacked, the material of the first sub layer is non-doped aluminum gallium nitride, the material of the second sub-layer is non-doped aluminum indium nitride, and the aluminum component content of the first sub layer and the second sub layer gradually decreases along the stacking direction of gallium nitride-based light emitting diode epitaxial wafers. The method is advantaged in that crystal quality of the epitaxial wafer can be effectively improved, composite light emitting of carriers in an active layer is facilitated, and light emitting efficiency of LEDs is improved.