AlGaN-based ultraviolet LED epitaxial wafer and preparation method thereof

Abstract

The invention discloses an AlGaN-based ultraviolet LED epitaxial wafer and a preparation method thereof. The AlGaN-based ultraviolet LED epitaxial wafer comprises, in order from bottom to top, a substrate, a buffer layer, an N-type aluminum gallium nitride layer, a multi-quantum well layer, an electron blocking layer, a P-type aluminum gallium nitride layer and a P-type gallium nitride layer; theelectron blocking layer comprises a first layer, a second layer and a third layer in order from bottom to top; the first layer and the third layer are both AlxGa1-xN layers, wherein the first aluminumcomponent content x is fixed; the second layer is AlyGa1-yN layer, wherein the second aluminum component content y is gradually changed, an initial value of the y is the x, and the y is gradually decreased from the x; the thickness of the first layer is smaller than the thickness of the second layer and the thickness of the third layer. The invention improves the luminous power and internal quantum efficiency of the ultraviolet LED by setting three aluminum gallium nitride layers having different thicknesses and different Al components as the electron blocking layer, thereby improving the performance of the ultraviolet LED.

Description

technical field [0001] The invention relates to the technical field of semiconductor optoelectronic devices, in particular to an AlGaN-based ultraviolet LED epitaxial wafer and a preparation method thereof. Background technique [0002] With the continuous development of light emitting diode (Light Emitting Diode, LED) technology, ultraviolet light emitting diodes are becoming more and more important in the commercial field, and have great application value. Moreover, compared with the traditional ultraviolet light source mercury lamp, ultraviolet LED has the advantages of super long life, no heat radiation, high energy, uniform irradiation, high efficiency, small size and no toxic substances, which makes ultraviolet LED the most likely Replace the traditional UV light source. Therefore, UV LEDs are receiving more and more attention from researchers. [0003] At present, the preparation of ultraviolet LED epitaxial wafers mainly uses III-nitride AlGaN (aluminum gallium nit...

AI Technical Summary

Problems solved by technology

However, it is still difficult to prepare high-quality UV LEDs using AlGaN materials

[0004] At present, the use of AlGaN materials to prepare ultraviolet LEDs has the following defects: 1) the high defect density of group III nitride materials with high Al composition leads to serious non-radiative recombination; 2) the strong polarization field causes energy band bending, resulting in large leakage of some electrons

This makes the ultraviolet LED face the major challenge of efficiency drop effect, that is, when the injection current of the ultraviolet LED is relatively small, the efficiency of the LED increases slowly; when the injection current continues to increase, the efficiency of the LED decreases with the increase of the injection current

Therefore, the current luminous power and internal quantum efficiency of AlGaN-based UV LEDs are relatively low.

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