High-luminous-efficiency ultraviolet LED epitaxial structure

Abstract

The invention provides a high-luminous-efficiency ultraviolet LED epitaxial structure. The high-luminous-efficiency ultraviolet LED epitaxial structure comprises a stress control layer, an n-type current expansion layer, an active region light-emitting layer, an electron blocking layer and a p-type current expansion layer which sequentially grow on the surface of a growth substrate, wherein the electron blocking layer is of a periodic structure formed by an ScaAl1-aN layer and a GaN layer, and 0.15 < a < 0.20. In an ScAlN / GaN short-period superlattice (a periodic structure formed by a ScaAl1-aN layer and a GaN layer), , a very thin ScAlN layer can generate a very large spontaneous polarization electric field to enable the energy band of the GaN layer to be bent enough. The activation energy of Mg is reduced. High-concentration holes are obtained, and the photoelectric efficiency of the LED is effectively improved.

Description

technical field [0001] The invention relates to the technical field of semiconductors, in particular to a high-efficiency ultraviolet LED epitaxial structure. Background technique [0002] GaN-based LEDs usually use a Mg-doped p-type wide bandgap AlGaN layer as the electron blocking layer on the multiple quantum well barrier structure. Although it can effectively block hot electrons from leaking to the p layer, the hole concentration of p-type AlGaN is low, which is not conducive to maintaining the light efficiency of the LED under the high current working condition of the LED. Recently, a short-period superlattice structure based on p-type AlGaN / GaN has been used as an electron blocking layer for LEDs. In the p-type AlGaN / GaN short-period superlattice structure, the polarization electric field bends the energy band of the GaN layer, which reduces the activation energy of Mg, thereby generating a higher concentration of holes in the GaN layer. [0003] However, there are s...

AI Technical Summary

Problems solved by technology

First, in order to bend the energy band of the GaN layer enough to reduce the activation energy of Mg, the thickness of the AlGaN layer needs to be controlled in the range of 4nm to 8nm, which hinders the transport of holes in the vertical direction.

Secondly, there is still stress between the AlGaN / GaN short-period superlattice and the last GaN barrier of the quantum well, which leads to a decrease in the barrier height of AlGaN and weakens the electron blocking effect

Images