A deep ultraviolet LED with algan/h-bn multi-quantum well structure and its preparation method

Abstract

The invention discloses a deep ultraviolet LED with an AlGaN / h-BN multi-quantum well structure, which comprises: a substrate, an AlN template layer, an n-type Al x Ga 1‑x N layer, Al y Ga 1‑y N / h‑BN multiple quantum well layer, p-type Al z Ga 1‑z N layer, p-type GaN contact layer. Al y Ga 1‑y N / h‑BN multiple quantum well layers including: Al y Ga 1‑y N quantum well layer and h-BN quantum barrier layer; wherein, Al y Ga 1‑y The range of Al composition y in the N quantum well layer is 0.5≤y≤0.7, and the thickness is 2-4nm; the thickness of the h-BN quantum barrier layer is 5-10nm. The disclosure can improve the problems of difficult hole injection, electron leakage and mismatch stress of the deep ultraviolet LED, thereby improving the luminous efficiency of the deep ultraviolet LED.

Description

technical field [0001] The present disclosure relates to the field of semiconductor optoelectronic devices, in particular to a deep ultraviolet LED with an AlGaN / h-BN multiple quantum well structure and a preparation method thereof. Background technique [0002] Compared with traditional UV light source mercury lamps, AlGaN-based deep UV LEDs have many advantages, such as non-toxic and environmentally friendly, simple structure, portable and unbreakable, low operating voltage, high luminous efficiency, adjustable wavelength, and long life. Air purification, water treatment, optical information storage and other fields have huge application potential. However, compared with the commercialized GaN-based blue LEDs, there are still many technical difficulties 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 DUV LEDs ...

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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