Deep ultraviolet LED with AlGaN/h-BN multi-quantum well structure and preparation method of deep ultraviolet LED

Abstract

The invention discloses a deep ultraviolet LED with an AlGaN / hBN multi-quantum well structure. The deep ultraviolet LED sequentially comprises a substrate, an AlN template layer, an n-type AlxGa1-xN layer, an AlyGa1-yN / h-BN multi-quantum well layer, a p-type AlzGa1-zN layer and a p-type GaN contact layer from bottom to top. The AlyGa1-yN / h-BN multi-quantum well layer comprises an AlyGa1-yN quantumwell layer and an h-BN quantum barrier layer; the range of an Al component y in the AlyGa1-yN quantum well layer is that y is more than or equal to 0.5 and less than or equal to 0.7, and the thickness is 2-4nm; and the thickness of the h-BN quantum barrier layer is 5-10 nm. According to the invention, the problems of hole injection difficulty, electron leakage and mismatch stress of the deep ultraviolet LED can be improved, so that the luminous efficiency of the deep ultraviolet LED is improved.

Description

Technical field [0001] The present disclosure relates to the field of semiconductor optoelectronic devices, and more particularly to deep ultraviolet LEDs and preparation methods of AlGaN / H-BN multi-quantum well structures. Background technique [0002] AlgaN-based deep UV LEDs have non-toxic environmental protection, simple structural, non-smoky, smooth working voltage, high lighting, high wavelength, long life, etc., in white lighting, sterilization, Air purification, water treatment, optical information storage and other fields have huge application potential. However, relative to commercial GAN-based blue LEDs, AlgaN base deep UV LEDs have many technical problems to be enrolled, especially in terms of luminous efficiency. [0003] Due to the lack of homogeneous substrates, AlgaN base deep UV LEDs are typically grown on heterogeneous substrates such as sapphire, Si, SiC, while lattice mismatch and thermal loss between heterogeneous substrates make deep UV LEDs A larger misma...

AI Technical Summary

Problems solved by technology

However, compared with the commercialized GaN-based blue LEDs, there are still many technical problems to be overcome in the commercial application of AlGaN-based deep ultraviolet LEDs, especially the luminous efficiency needs to be improved urgently.

[0003] Due to the lack of homogeneous substrates, AlGaN-based deep ultraviolet LEDs are usually grown on heterogeneous substrates such as sapphire, Si, SiC, etc., and the lattice mismatch and thermal mismatch between heterogeneous substrates will cause deep ultraviolet LEDs Accumulate a large mismatch stress, and the piezoelectric polarization electric field generated by the mismatch stress will cause the energy band tilt of the multi-quantum well region, and then induce the quantum confinement Stark effect, which will reduce the luminous efficiency of the deep ultraviolet LED; at the same time, the mismatch Excessive accumulation of stress will also cause cracks in the LED epitaxial layer, which will not only cause LED leakage, but also absorb ultraviolet light and affect the LED light output power

[0004] In addition, in deep ultraviolet LEDs, the hole concentration of its high Al composition p-type AlGaN layer is low, and the hole mobility is significantly lower than the electron mobility, which leads to the injection of electrons and holes into the multi-quantum well structure. The concentration is unbalanced, and a large number of electrons cannot recombine in the active region of the quantum well and leak directly to the p-type region, resulting in electron leakage.

When the injection current increases, the electron and hole concentration imbalance in the quantum well structure will be further aggravated, and more electron leakage will occur, resulting in the low effect of deep ultraviolet LED luminous efficiency (droop effect).

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