High-brightness light-emitting diode epitaxial wafer and preparation method thereof

The invention discloses a high-brightness light-emitting diode epitaxial wafer. The high-brightness light-emitting diode epitaxial wafer includes a substrate and further includes a buffer layer, an un-doped gallium nitride layer, an N-type layer, a quantum well layer, and a P-type layer which sequentially grow along the surface of the substrate; the buffer layer includes first gallium nitride layers and second gallium nitride layers that alternately grow; the first layer and the last layer of the buffer layer are both the first gallium nitride layers; the growth temperature of the first gallium nitride layers is lower than the growth temperature of the second gallium nitride layers; the growth of the P-type layer includes at least two growth stages; and each growth stage includes processesof high-temperature growth, annealing and cooling, and low-temperature growth. The buffer layer of the high-brightness light-emitting diode epitaxial wafer disclosed by the invention avoids the occurrence of non-radiative re