Red light LED epitaxial structure and preparation method thereof

The invention provides a red light LED epitaxial structure and a preparation method thereof.The red light LED epitaxial structure sequentially comprises a substrate, a first type semiconductor layer, an active layer and a second type semiconductor layer from bottom to top, and the active layer sequentially comprises a front quantum well structure and a main quantum well structure from bottom to top; the preposed quantum well structure is a periodic structure formed by alternately growing a preposed well layer and a preposed barrier layer, the preposed well layer contains an Al component, and the Al component of the preposed well layer in the previous period is smaller than the Al component of the preposed well layer in the next period. Through the arrangement of the front quantum well structure, the luminous intensity and the temperature characteristic of the red light LED can be improved. 本发明提供了一种红光LED外延结构及其制备方法，其中，红光LED外延结构从下至上依次包括：衬底、第一型半导体层、有源层以及第二型半导体层，有源层从下至上依次包括前置量子阱结构和主量子阱结构，前置量子阱结构为前置阱层和前置垒层交替生长形成的周期