7results about How to "Improve hole injection efficiency" patented technology

The invention provides a semiconductor laser element and a light-emitting device. An electron blocking layer is arranged between a second coating layer and a second waveguide layer of the semiconductor laser element; the second semiconductor layer is doped with a P-type dopant, the P-type dopant in the electron blocking layer has at least one doping concentration peak, the doping concentration of Mg at the doping concentration peak is smaller than the maximum doping concentration of the P-type dopant in the second semiconductor layer, and the P-type dopant in the electron blocking layer gradually approaches the direction of the electron blocking layer. The doping concentration of the P-type dopant in the second coating layer is provided with a plurality of subareas, and the doping concentration curve of the P-type dopant is gradually reduced along the plurality of subareas. Due to the descending trend of the Mg doping concentration in the second semiconductor layer, it can be guaranteed that the second semiconductor layer can provide enough holes, the hole injection efficiency in the quantum well layer is improved, and the light emitting efficiency is improved. Meanwhile, due to the arrangement of the second semiconductor layer, light absorption can be reduced, and the light emitting effect of the device is improved.

The application discloses a SiC MOSFET device with improved diode reverse recovery characteristics and a preparation method thereof, and relates to the technical field of semiconductors.The device comprises, from bottom to top, a drain metal layer, an N-type substrate, a first N-type drift layer, a second N-type drift layer, a P-body region, a P+ contact region, an ohmic contact alloy layer and a source metal layer; a P++ layer extending downward is arranged in the middle of the top surface of the second N-type drift layer; a groove region extending into the P++ layer (4) is arranged on the top surface of the P+ contact region; a gate oxide layer is arranged in the groove region; a filled polysilicon gate is arranged in the gate oxide layer; N+ regions extending downward from the top surface of the P+ contact region into the P-body region are arranged on both sides of the groove region; an isolation medium layer is deposited on the P+ contact region, and the isolation medium layer completely covers the top end surfaces of the polysilicon gate and the gate oxide layer.The application can reduce the deep diffusion of carriers, make the recombination of the carriers better distributed in the surface region of the PN junction, and guarantee the long-term reliability of the device.

A light emitting element (2) includes a light emitting layer (23) disposed between an anode (21) and a cathode (25). The light emitting layer includes first quantum dots (31) and an additive (40). The first quantum dots are in direct contact with a layer (22) adjacent to the light emitting layer on the anode side, or are adjacent to the layer (22) via an organic ligand (41), or are adjacent to the layer (22) via a semiconductor.

This application discloses an AlGaInP red micro-LED chip with a high Al composition polarization-induced barrier layer and its fabrication method. The core innovation lies in the use of an Al composition in the barrier layer of the quantum well structure. x2 Ga 1‑x2 ) y2 InP gradually changes to Al 0.5 In 0.5 The high Al composition structure of P elevates the valence band level to 250-320 meV, significantly enhancing carrier confinement capability. Simultaneously, the barrier layer employs low-concentration p-type doping, inducing the formation of a three-dimensional hole gas through the polarization effect of the gradual Al composition change, allowing the hole concentration to break through the doping limit and avoiding the luminescence quenching problem caused by high doping. This solves the core problems of insufficient carrier confinement, low hole injection efficiency, and poor high-temperature stability in existing red Micro-LED chips. The device's external quantum efficiency, high-temperature retention rate, and long-term reliability are all significantly improved. The fabrication process is compatible with existing production lines and is applicable to multiple fields.

The present invention relates to a compound and its application, wherein the compound has a structure shown in Formula I, and a naphthalene ring structure is introduced in the para position of aromatic amine to increase the molecular conjugation system, which is beneficial to strengthen the transmission of charge and improve the charge mobility of the molecule; at the same time, a condensed aromatic ring of a specific structure is introduced in the ortho position of aromatic amine, which can first increase the conjugation level of the entire molecule and improve the injection and transmission capacity of holes; secondly, the steric hindrance of the molecule can be increased to prevent the molecule from being excessively planarized and forming crystals at high temperatures. The compound of Formula I exhibits good hole injection and migration performance, and when it is used as a hole transport material or electron blocking material in an organic electroluminescent device, the efficiency roll-off of the device can be suppressed, and the hole injection and migration efficiency in the device can be effectively improved, thereby ensuring that the device obtains the excellent effect of low starting voltage and prolonging the life of the device.

The application discloses a polymer light-emitting diode containing a full conjugated self-assembled monolayer and a preparation method thereof, and relates to the technical field of optoelectronic devices. The organic light-emitting diode comprises, from bottom to top, an anode, a full conjugated self-assembled monolayer, a light-emitting layer, a lithium fluoride layer and a cathode; wherein the material of the anode is selected from indium tin oxide and / or fluorine-doped indium tin oxide; and the material of the full conjugated self-assembled monolayer is a full conjugated carbazole phosphoric acid derivative of one or more of the following structures: The full conjugated carbazole phosphoric acid derivative is used as anode modification material, can form an ultrathin self-assembled film, enhance light transmittance, can adjust the ITO work function, reduce the energy difference between the anode and the light-emitting polymer, improve the hole injection efficiency, and thus improve the light-emitting efficiency. In addition, the full conjugated carbazole phosphoric acid derivative is simple to synthesize, low in price, soluble in alcohol-based environmentally-friendly non-halogenated organic solvents, and suitable for carrying out liquid-phase process film forming, and is green and environmentally-friendly.

The application discloses a spin light emitting diode based on a mixed hole transport layer and a preparation method thereof. The spin light emitting diode based on the mixed hole transport layer comprises a substrate layer, a first electrode layer, a hole injection layer, a mixed hole transport layer, a chiral perovskite active layer (or a spin injection layer and a quantum dot layer), an electron transport layer and a second electrode layer which are sequentially arranged. The mixed hole transport layer comprises at least two different materials and has the characteristics of the at least two different materials, so that the performance of the device in all aspects can be considered more than that of a single material. The different materials in the mixed hole transport layer jointly form a gradient HOMO energy level, reduce a hole injection barrier, increase a carrier injection channel, so that the device has higher photoelectric performance, and more holes reach the chiral perovskite material to realize spin polarization, so that the device has a higher electroluminescence asymmetry factor (g CP‑EL ). As can be seen, the device has higher g CP‑EL and higher photoelectric performance.