Algan-based deep ultraviolet LED epitaxial structure and preparation method of mg-doped quantum well

Abstract

The invention discloses an AlGaN-based deep-ultraviolet LED epitaxial structure and a preparation method thereof, which utilize Mg-doped quantum wells to enhance luminous efficiency. The deep ultraviolet LED structure includes a substrate, a buffer layer, an AlN layer, a superlattice stress regulation / dislocation filter layer, a non-doped AlGaN layer, an n-type AlGaN layer, a Mg-doped active light-emitting region multi-quantum well layer, A p-type AlGaN layer and a p-type GaN contact layer. In the invention, Mg impurity is doped in the middle third of the well layer of the multi-quantum well active luminescent layer of the LED, so as to improve the internal quantum efficiency and light extraction efficiency of the LED. Compared with the non-doped multiple quantum well structure, the Mg-doped multiple quantum well structure can suppress the quantum confinement Stark effect, improve the spatial overlap of electron and hole wave functions and radiative recombination efficiency, and provide more holes Participate in radiative recombination and improve internal quantum efficiency. Moreover, Mg doping can also introduce a local strain field, increase the compressive strain in the quantum well, increase the ratio of TE polarized light, and finally improve the light extraction efficiency of AlGaN-based deep ultraviolet LEDs.

Description

technical field [0001] The invention belongs to the technical field of semiconductor optoelectronics, and relates to a semiconductor device, in particular to an AlGaN-based deep ultraviolet LED epitaxial structure and a preparation method thereof which utilizes Mg-doped quantum wells to enhance luminous efficiency. Background technique [0002] AlGaN-based semiconductor deep ultraviolet LEDs have great application value and wide market in high-density optical storage, white lighting, printing, sterilization, air and water purification, non-line-of-sight military security communications, biochemistry, medical diagnosis, etc. space. In the past two decades, thanks to the efforts of researchers and the industry, AlGaN-based deep ultraviolet LEDs have achieved great development and progress. However, the current luminous efficiency of AlGaN-based deep ultraviolet LEDs is still affected by the quantum well structure. AlGaN material has a wurtzite crystal structure, and the intri...

AI Technical Summary

Problems solved by technology

Compared with the TE polarized light emitted in the forward direction, the TM polarized light propagating sideways is more likely to generate multiple total reflections and reabsorption inside the device, so it is more difficult to be extracted

In deep-UV LEDs with shorter wavelengths, the luminescence of quantum wells is dominated by TM polarized light, resulting in low light extraction efficiency

Experimentally reported light extraction efficiencies of AlGaN-based deep-UV LEDs are less than 5% in most device structures, which further limits the overall luminous efficiency of LEDs.

[0004] In order to solve the problem of low internal quantum efficiency caused by the quantum confinement Stark effect, epitaxial AlGaN on the semipolar and nonpolar surfaces with weaker polarization fields can avoid the quantum confinement Stark effect caused by strong polarization, but It is difficult to grow semi-polar and non-polar materials, and the stacking fault density is high, so it is difficult to apply

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