This invention relates to the field of LED technology, and particularly to a high-efficiency violet LED epitaxial structure and its growth method. The epitaxial structure, from bottom to top, includes: a patterned AlGaN template substrate and a GaN-based epitaxial layer. The patterned AlGaN template substrate sequentially includes a growth substrate, a buffer layer, an AlGaN layer, and a
mask layer, wherein the
mask layer is a periodically patterned
mask. The GaN-based epitaxial layer sequentially includes: an AlGaN capping layer, an n-type
semiconductor layer, a
stress relief layer, a multi-
quantum-well active region, an
electron blocking layer, and a p-type
semiconductor layer. The n-type
semiconductor includes an Alx3Ga1-x3N layer with an Al composition of 0.01 ≤ x3 ≤ 0.05 and x3 ≥ x2. This invention effectively blocks
dislocation propagation and reduces defect density through the synergistic design of the patterned AlGaN template substrate and the laterally epitaxially grown AlGaN capping layer; and achieves progressive
stress relief and light absorption suppression through the
gradient increase of Al composition in each layer of the all-AlGaN-based structure.