99results about How to "Increase electron concentration" patented technology

The present invention discloses an LED structure, wherein an N-type current spreading layer is interposed between N-type semiconductor layers to uniformly distribute current flowing through the N-type semiconductor layer. The N-type current spreading layer includes at least three sub-layers stacked in a sequence of from a lower band gap to a higher band gap, wherein the sub-layer having the lower band gap is near the substrate, and the sub-layer having the higher band gap is near the light emitting layer. Each sub-layer of the N-type current spreading layer is expressed by a general formula In_xAl_yGa_(1-x-y)N, wherein 0≦x≦1, 0≦y≦1, and 0≦x+y≦1.

A nitride semiconductor device includes: a first semiconductor layer made of first nitride semiconductor; a second semiconductor layer formed on a principal surface of the first semiconductor layer and made of second nitride semiconductor having a bandgap wider than that of the first nitride semiconductor; a control layer selectively formed on, or above, an upper portion of the second semiconductor layer and made of third nitride semiconductor having a p-type conductivity; source and drain electrodes formed on the second semiconductor layer at respective sides of the control layer; a gate electrode formed on the control layer; and a fourth semiconductor layer formed on a surface of the first semiconductor layer opposite to the principal surface, having a potential barrier in a valence band with respect to the first nitride semiconductor and made of fourth nitride semiconductor containing aluminum.

A lithium-ion battery and a lithium-ion battery electrode structure are disclosed. The lithium-ion battery electrode structure comprises a metal foil and a semiconductor nanowire matrix. The semiconductor nanowire matrix is disposed on the metal foil, and is doped with dopants.

An Al component gradually-changed N-type LED structure and a preparation method thereof are disclosed. The Al component gradually-changed N-type LED structure successively comprises, from bottom to top, a substrate, a nucleating layer, a buffer layer, an N-type Al<Y>In<X>Ga<1-X-Y>N layer, a multi-quantum well light-emitting layer, and a P-type GaN layer. In the N-type Al<Y>In<X>Ga<1-X-Y>N layer, X is more than or equal to 0 but less than or equal to 1, and Y is more than 0 but less than 1. An Al component in an N-type GaN layer is gradually changed. The method comprises the following steps of: (1) growing the nucleating layer on a processed substrate; (2) growing a non-doped gallium nitride buffer layer on the nucleating layer; (3) growing the N-type Al<Y>In<X>Ga<1-X-Y>N layer on the buffer layer; (4) growing the multi-quantum well light-emitting layer on the N-type Al<Y>In<X>Ga<1-X-Y>N layer, wherein the multi-quantum well light-emitting layer is formed by periodically and alternately superposed InGaN potential well layers and GaN barrier layers; and (5) growing the P-type GaN layer on the multi-quantum well light-emitting layer. An N-type region is prepared by an Al component gradually-changed mode, thereby improving electron concentration and an antistatic effect, essentially improving GaN film quality, enhancing current expansion capability, and increasing light extraction efficiency.

The invention relates to a method for reducing sheet resistance of a graphene thin film, comprising the following step of soaking the graphene thin film and a substrate in a solution with an electron or hole donation capability for a certain time, wherein the solution in the step is one or mixed solution with an electron donation capability of low-valence solutions of heavy metal inorganic acid, organic alcohol and organic amine; or the solution in the step is one or mixed solution with a hole donation capability of a nonmetal inorganic acid solution and an organic alkane solution. The invention has the beneficial effects that: after the graphene thin film arranged on the substrate is soaked in a solution with the electron donation capability, the solution captures holes in the graphene thin film, thus the consistency of electrons in the graphene thin film is increased, and the sheet resistance of the graphene thin film is reduced.

The invention provides a deep UV LED, which includes a substrate; an undoped buffer layer located on the surface of the substrate; an N type AlGaN layer on the undoped buffer layer and far away from the surface of the substrate; a multi-quantum well structure on the undoped buffer layer and far away from the surface of the substrate; and a P type AlGaN structure on the multi-quantum well structure and far away from the surface of the substrate, wherein the V type Al component of the P type AlGaN structure is gradually changed. The P type AlGaN structure with the gradually changed V type Al component is subjected to polarization doping. The Al component in the P type AlGaN structure with the gradually changed V type Al component is different from the Al component in the multi-quantum well structure. The P type AlGaN structure with the gradually changed V type Al component is far away from a P type GaN layer on the surface of the substrate. Based on the P type AlGaN structure with the gradually changed V type Al component, obtained electron holes are higher in concentration. Therefore, the internal quantum efficiency and the emission power of the UV LED are improved.

A composite thermal barrier material. The material includes a support layer coated on one or both sides with an infrared active material to improve thermal retention characteristics. The support layer is typically a flexible organic or polymer material. The infrared active material increases reflectance of thermal infrared radiation and reduces the flow of heat from the interior side of the barrier to the external surroundings. The infrared active material operates through vibrational absorption in the infrared and/or free carrier absorption. Representative infrared active materials include oxides, transparent conductors, and nanoscale metals.

The invention provides a silicon-doped gallium nitride nanoribbon ultraviolet detector and a preparation method thereof. The method comprises the following steps: (1) performing pattern photoetching and potassium hydroxide wet etching on a silicon substrate which is plated with silicon dioxide serving as a mask; (2) growing a silicon-doped gallium nitride nanoribbon on the groove side wall of the pattern; (3) peeling the nanoribbon, and transferring the peeled nanoribbon to the silicon dioxide plated silicon wafer substrate; and (4) plating a silver electrode on the nanoribbon of the substrate obtained in the step (3) so as to obtain the silicon-doped gallium nitride nanoribbon ultraviolet detector. According to the technical scheme, the photoswitch ratio and optical gain of a micro/nano measurement gallium nitride ultraviolet detector can be improved. Experimental results indicate that the silicon-doped gallium nitride nanoribbon ultraviolet detector has a photoswitch ratio of 5.4*10<4>, optical gain and optical sensitivity of 8.8*10<5> and 2.3*10<-5>A/W respectively.

The invention provides a preparation method and application of a graphene-wrapping fluorine-doped lithium titanate nanowire and belongs to the technical field of lithium-ion battery energy material production. According to the preparation method, industrial-grade TiO2 which is low in cost is used as a raw material, a hydrothermal method is used as a basis, through two-step conversion, industrial-grade TiO2 which is low in cost is converted into the lithium titanate nanowire in a specific shape, the cost of forming the lithium titanate nanowire is greatly lowered, and industrial production andapplication are facilitated. Meanwhile, the lithium titanate nanowire is doped with liquid-phase fluorine and wrapped by graphene in situ, and the electric conductivity of the lithium titanate material is increased through the synergistic effect of the shape, ion doping and graphene wrapping. The obtained graphene-in-situ-wrapping fluorine-doped lithium titanate nanowire has the charging and discharging specific capacity close to a theoretical value, and the rate capability of the material is remarkably increased.

The invention provides a nitride semiconductor device and a manufacturing method thereof. In the invention, n-type and p-type nitride semiconductor layers are formed on a substrate, and an active layer is formed therebetween. The n-type nitride semiconductor layers include first and second n-type GaN layers disposed in the order of distance from the active layer. In addition, in the nitride semiconductor device of the invention, an Al_xGa_1-xN layer, where 0<x<1, is interposed between the first and second n-type GaN layers, thereby forming a two-dimensional electron gas layer at interfaces of the first and second n-type GaN layers.

The invention provides a novel silver-introduced hafnium-nitride-membrane high-infrared-reflection durable material and relates to the field of infrared reflection membrane materials. The material is a HfN-Agx membrane formed by HfN and Ag, the HfN-Agx membrane has a solid solution structure comprising HfN and Ag, and the content of Ag is 0.8-3.8at.%. A preparation method of the durable material includes: selecting a silicon wafer or a glass substrate to use as the substrate, placing a Hf target and a Ag target into a magnetic control sputtering chamber, vacuumizing, setting magnetic control sputtering parameters, feeding N2 and Ar gas, and depositing the HfN-Agx membrane onto the substrate. The durable material is good in infrared reflection performance and excellent in durability, can be hopefully used as the high-infrared-reflection durable membrane in harsh environments with high-speed solid-liquid particle impact, high temperature and corrosive liquid and gas, and can also be applied to the surface of an optical reflection device.

The invention discloses a light emitting diode epitaxial wafer and a preparation method thereof, and belongs to the technical field of semiconductors. The light-emitting diode epitaxial wafer comprises a substrate, an N-type semiconductor layer, a stress release layer, an active layer and a P-type semiconductor layer, wherein the N-type semiconductor layer, the stress release layer, the active layer and the P-type semiconductor layer are sequentially stacked on the substrate; the stress release layer comprises a plurality of composite structures which are stacked in sequence, wherein each composite structure comprises a first sub-layer, a second sub-layer, a third sub-layer and a fourth sub-layer which are stacked in sequence; the first sub-layer is made of non-doped indium gallium nitride, the second sub-layer is made of non-doped aluminum nitride, the third sub-layer is made of silicon nitride, and the fourth sub-layer is made of non-doped gallium nitride. According to the light-emitting diode epitaxial wafer, the photoelectric property of the LED is finally improved.

The invention discloses an ion-implanted one-dimensional electron gas GaN-based HEMT (high electron mobility transistor) device and a preparation method. The problems of poorer high-temperature high-voltage characteristics, frequency characteristics and power characteristics of the conventional one-dimensional electron gas device are mainly solved. The device comprises a substrate, buffer layer, a potential barrier layer, a passivation layer and a protective layer from bottom to top, wherein a source and a drain are arranged at two ends on the potential barrier layer respectively; the passivation layer is positioned on the potential barrier layer between the source and the drain; a gate trough is formed in the passivation layer, and a gate is arranged in the gate trough; the buffer layer is made from GaN, and the potential barrier layer is made from AlGaN; anions are implanted into local areas on the potential barrier layer, and the areas where the anions are implanted are a plurality of spaced strips; the widths of areas where the anions are not implanted between the strips are at a nanometer order of magnitude, and a one-dimensional electron gas is formed in heterogeneous junctions below the areas where the anions are implanted. Compared with Si-based and GaAs-based devices, the device has good high-temperature high-voltage characteristics, good frequency characteristics and good power characteristics, and a one-dimensional electron gas device with super-high speed and low power consumption can be manufactured.

The invention discloses a method and device for manufacturing a micro-fluidic chip with a femtosecond plasma grating. The method is characterized in that two or more beams of femtosecond pulse lasersact on quartz glass together at a certain included angle and converge in the quartz glass, and when pulses achieve synchronization in time domain, pulses of two beams of light interfere; under the constraint of an interference field, only one filament is formed in a place where interference is constructive; and multiple filaments are arranged equidistantly in space to form the plasma grating; andthe device for manufacturing the micro-fluidic chip comprises a plasma grating light path, a micro-channel processing platform and a hydrofluoric acid ultrasonic pool. Compared with the prior art, themethod and the device have the advantages of increasing the manufacturing speed of the quartz glass micro-fluidic chip and improving the roughness quality of a micro-channel wall surface; especiallythe micro-fluidic chip of a three-dimensional structure can be conveniently processed; a new preparation method is provided for manufacturing of micro-channel chips, and the new preparation has uniqueadvantages especially in processing the micro-fluidic chip with an ultrafast optical technology.