Abstract: An epitaxial structure for an LED is provided. The epitaxial structure includes a patterned epitaxial defect barrier layer disposed over a first portion of a substantially flat substrate to expose a second portion of the substrate. The epitaxial structure also includes a patterned buffer layer over the second portion of the substrate. The epitaxial structure further includes a first semiconductor layer over the patterned buffer layer and the patterned epitaxial defect barrier layer, an active layer over the first semiconductor layer, and a second semiconductor layer over the active layer.