32results about How to "Optimizing the band structure" patented technology

The invention provides a near ultraviolet LED adopting an MOCVD technology and a preparation method thereof, and relates to the technical field of semiconductors. The near ultraviolet LED comprises asubstrate, and a buffer layer, a high-temperature layer, an n-type AlmGa1-mN layer, a light-emitting active region, a p-type electron blocking layer, a p-type AlnGa1-nN layer and a contact layer whichare sequentially grown on the substrate, wherein the material of the light-emitting active region comprises In < x > Ga < 1-x > N and Al < y > Ga < 1-y > N, the material of the p-type electron blocking layer comprises Al < y 1> In < x 1> Ga < 1-y1-x1 > N, 0.001<=x<y<=1, and y, m and n are all less than y1. The near ultraviolet LED can effectively improve the electron limiting effect and the holeinjection efficiency, so that the quantum efficiency and the light emitting efficiency of the device are improved.

The present invention belongs to two-dimensional MoS 2 The technical field of preparation of base nanocomposite materials relates to a hollow sandwich laminated molybdenum disulfide based nanocomposite material and its preparation method. It is a hollow structure and includes carbon layers, MoS 2 layers and carbon layers. Using SiO 2 The microspheres are used as templates, which are sequentially coated with carbon layers, MoS 2 layer and carbon layer, then etched SiO 2 Hollow sandwich structure MoS was prepared 2 based nanocomposites. The unique hollow sandwich laminated structure of the obtained product is conducive to exposing more active sites, improving electrical conductivity, reducing agglomeration, and improving the electrocatalytic performance of the material. Therefore, the preparation of this composite material offers the possibility of its potential application in many fields.

The invention discloses an ultraviolet-light gallium nitride semiconductor light emitting diode with gradient electron barrier layers. By means of energy band engineering design and optimization, six kinds of superlattice-like AlGaN electron barrier layers with different changing types are introduced to an epitaxial structure of the light-emitting diode so as to realize the change of an aluminum component, so that the polarization effect in the electron barrier layers is changed, and high hole injection is realized so as to solve the problems of low P-type doping efficiency and insufficient hole concentration in the ultraviolet-light semiconductor light emitting diode.

The invention relates to an n-p heterogeneous core-shell array gas-sensing material and a preparation method, in particular to a p-type nano-NiO as the core and an n-type nano-SnO 2 The core-shell monomer is a shell, and the whole is a highly ordered nano-array of NiO@SnO 2 Core-shell array gas-sensing material and preparation method. On the one hand, the gas-sensitive material of the invention avoids the depletion of interface electrons caused by the direct exposure of the p-type NiO in the core layer to the air; on the other hand, it utilizes the n-type SnO in the shell layer 2 The energy band structure of the gas-sensing material is improved, and the overall ordered array increases the active contact point, which improves the sensitivity of the gas-sensing material to gas. The method adopted in the present invention has a wide range of sources of raw materials and low prices; the obtained n-p heterogeneous NiO@SnO 2 The core-shell array gas-sensing material has high sensitivity and strong selectivity.

The invention claims to protect a low-power-consumption waveguide photodetector structure with optical isolation between the photosensitive mesa and the N-contact mesa. The structure integrates the light waveguide and the photodiode on a semi-insulating substrate. Among them, the photodiode has an optimized energy band structure, doping distribution and epitaxial layer thickness, mainly including a non-depleted P-type light absorption layer with a linear gradient doping distribution, and an N-type electron collection layer (non-depleted) with a linear gradient doping distribution. light absorbing layer), and a graded bandgap spacer layer with a sandwich dipole doping profile between the absorbing layer and the collecting layer. By making a groove on the N mesa and depositing a metal thin film electrode to optically isolate the photosensitive mesa from the N contact mesa, thereby improving the light confinement of the optical waveguide; making a mesa isolated from the N mesa at the end of the optical waveguide and depositing The upper metal thin film is used as a light reflector to increase the effective absorption length of the device, which is a technical solution to alleviate the mutual restriction between the bandwidth of the photodetector and the quantum efficiency.