Deep ultraviolet LED with high external quantum efficiency and production method thereof

Abstract

The invention relates to a deep ultraviolet LED with high external quantum efficiency and a production method thereof. The deep ultraviolet LED comprises a patterned sapphire substrate, the upper surface and the lower surface of the patterned sapphire substrate are respectively provided with a micro-dome-shaped structure arranged in a regular hexagonal array shape, the upper surface of the patterned sapphire substrate is provided with an epitaxial lamination layer, the epitaxial lamination layer is provided with an mesa step exposing an n-AlGaN layer, and a nano-particle array of an Al-SiO2 core-shell structure is arranged on the side, close to the multiple quantum wells in the epitaxial laminated layer, of the surface of the n-AlGaN layer. By using the micro-dome type patterned sapphire substrate which is symmetrical up and down, the light emitting probability can be improved, the light extraction efficiency can be increased, the defect density of the AlGaN epitaxial layer can be reduced, the non-radiative recombination can be decreased, and the internal quantum efficiency can be improved; and the nano-particle array resonates with photons emitted by an LED through the local surface plasmon resonance effect of Al nanoparticles so that the field intensity near a quantum well is enhanced, and the internal quantum efficiency is improved.

Description

technical field [0001] The invention relates to the field of light emitting diodes, in particular to a deep ultraviolet LED with high external quantum efficiency and a preparation method thereof. Background technique [0002] Deep ultraviolet LED refers to a light-emitting diode with a light-emitting band between 200nm and 300nm, because it has great potential application value in many application fields such as exciting white light, biochemical detection, sterilization, environmental purification, polymer curing, and short-distance safe communication. And received much attention. In addition, ultraviolet LEDs based on aluminum gallium nitride (AlGaN) materials are also the main trend in the development of nitride technology and the development of third-generation semiconductor material technology, and have broad application prospects. Compared with traditional ultraviolet mercury lamps, AlGaN-based ultraviolet LEDs have many advantages such as long life, low voltage, adjus...

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Problems solved by technology

[0003] However, the development of deep ultraviolet LEDs is currently facing many challenges. Due to the high dislocation density of AlGaN materials with high Al composition, its internal quantum efficiency is much lower than that of blue LEDs. Due to the influence of polarization, the mode of some photons is converted from the transverse electric mode (TE) to the transverse magnetic mode (TM), and the electric field direction of the TM mode is parallel to the growth plane (c plane) of the LED, so its light wave The direction is perpendicular to the c-plane, that is, it is emitted laterally along the LED, which increases its incident angle. Due to the in-plane total reflection effect (TIR), most of the photons are absorbed inside or emitted from the side, which greatly affects The light extraction efficiency of the device is reduced, so the external quantum efficiency of the general deep ultraviolet LED is 5%, so it is of great research significance to improve the external quantum efficiency of the deep ultraviolet LED

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