Epitaxial wafer of ultraviolet light emitting diode and its preparation method

Abstract

The disclosure provides an epitaxial wafer of an ultraviolet light-emitting diode and a preparation method thereof, belonging to the field of light-emitting diodes. The epitaxial wafer includes: a substrate and an epitaxial layer deposited on the substrate, and the epitaxial layer includes a buffer layer, an undoped AlGaN layer, an N-type AlGaN layer, and a multilayer stacked on the substrate in sequence. A quantum well layer, an electron blocking layer, and a P-type AlGaN layer, the epitaxial layer also includes a reflective layer between the electron blocking layer and the P-type AlGaN layer, and the reflective layer is composed of several staggered bumps The protruding direction of the bump is the same as the deposition direction of the epitaxial layer and the cross-sectional area of ​​the bump decreases gradually along the deposition direction of the epitaxial layer. The present disclosure can greatly improve light extraction efficiency.

Description

technical field [0001] The disclosure relates to the field of light-emitting diodes, in particular to an epitaxial wafer of an ultraviolet light-emitting diode and a preparation method thereof. Background technique [0002] In recent years, many researchers have developed AlGaN-based high-brightness UV light-emitting diodes. The basic structure of an epitaxial wafer of an AlGaN-based ultraviolet light-emitting diode is usually a substrate, a buffer layer deposited on the substrate, an n-type doped layer, a multi-quantum well layer, an electron blocking layer and a p-type layer. [0003] When the light starts from the active region (multiple quantum well layer) and reaches the surface criticality, the light will be absorbed from the side or by the substrate due to total reflection, making the luminous efficiency low and affecting the external quantum efficiency. Therefore, how to improve the luminous efficiency of ultraviolet light-emitting diodes has become a hot spot in in...

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Problems solved by technology

[0004] In the process of realizing the present disclosure, the inventors found that there are at least the following problems in related technologies: first, the Al film only reflects the ultraviolet light directed to the substrate, and cannot reflect the ultraviolet light directed to the side; second, the reflected ultraviolet light needs to pass through The entire epitaxial layer is emitted toward the light-emitting surface, so that most of the reflected ultraviolet light is absorbed by the entire epitaxial layer again, reducing the reflectivity

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