Quantum well composite LED epitaxial structure with high luminous efficiency and preparation method thereof

Abstract

The invention relates to a quantum well composite LED epitaxial structure with high luminous efficiency and a preparation method thereof. The epitaxial structure is sequentially provided with a substrate, a buffer layer, an undoped GaN layer, an n-type AlGaN layer, an n-type GaN layer, an active layer, a P-type AlGaN layer, a P-type GaN layer and a P-type InGaN contact layer from the bottom up, wherein the active layer comprises a lower layer multi-quantum well structure, a constant temperature multi-quantum well structure and an upper layer multi-quantum well structure, the lower layer multi-quantum well structure is formed by periodically overlying an InGaN potential well layer and a GaN barrier layer, the constant temperature multi-quantum well structure is formed by periodically overlying a constant temperature InGaN potential well layer and a constant temperature GaN barrier layer, and the upper layer multi-quantum well structure is formed by periodically overlying the InGaN potential well layer and the GaN barrier layer. The preparation method is that the layers are sequentially prepared from the bottom up in a reaction chamber of metal organic chemical vapor deposition equipment. The epitaxial structure and the preparation method thereof can effectively reduce stress between well barrier interfaces, relieve bending of an energy band, and improve the efficiency of hole injection and electron injection to an active region and the radiative recombination efficiency.

Description

technical field [0001] The invention relates to an epitaxial structure of an active region LED (light emitting diode) capable of improving light extraction efficiency and a preparation method thereof, belonging to the technical field of LED epitaxy. Background technique [0002] In the early 1990s, the third-generation wide-bandgap semiconductor materials represented by nitrides made a historic breakthrough. Researchers successfully prepared blue-green and ultraviolet LEDs on gallium nitride materials, making LED lighting become possible. In 1971, the first gallium nitride LED die came out. In 1994, gallium nitride HEMTs appeared blue light GaN-based diodes with high electron mobility, and gallium nitride semiconductor materials developed very rapidly. [0003] Semiconductor light-emitting diodes have the advantages of small size, ruggedness, strong controllability of light-emitting bands, high luminous efficiency, low heat loss, low light decay, energy saving, and environm...

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Problems solved by technology

[0019] The present invention aims at the problems of low quantum efficiency and high stress in existing multi-quantum wells, and provides a quantum well combined L

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