Patent ID: 8536565

Claim:
A light-emitting device comprising: a substrate; a buffer layer, formed over the substrate, comprising nitrogen, a first group III element, and a second group III element; wherein a first portion of the buffer layer adjacent to the substrate comprises an atomic concentration of the first group III element greater than an atomic concentration of the second group III element, and a combined atomic concentration of the first group III element and the second group III element is greater than an atomic concentration of nitrogen; and wherein a second portion of the buffer layer located on the first portion of the buffer layer comprises an atomic concentration of the first group III element lower than an atomic concentration of the second group III element, and the second portion of the buffer layer comprises an atomic concentration of nitrogen greater than an atomic concentration of nitrogen of the first portion of the buffer layer; a first semiconductor layer formed over the buffer layer; a multi-quantum well light-emitting structure formed over the first semiconductor layer; and a second semiconductor layer formed over the multi-quantum well light-emitting structure.