Abstract: An LED manufacturing method includes steps of: providing a substrate including a first surface; forming a first portion of a first semiconductor layer on the first surface in a first atmosphere including a first carrier gas; and forming a second portion of the first semiconductor layer on the first portion in a second atmosphere including a second carrier gas; wherein a plurality of first cavities is formed on a surface of the first portion during forming the first portion; and wherein the plurality of first cavities is transformed to a plurality of second cavities during forming the second portion, and one of the second cavities includes a first inclined surface and a second inclined surface above the first inclined surface.

Abstract: An LED manufacturing method includes steps of: providing a substrate including a first surface; forming a first portion of a first semiconductor layer on the first surface in a first atmosphere including a first carrier gas; and forming a second portion of the first semiconductor layer on the first portion in a second atmosphere including a second carrier gas; wherein a plurality of first cavities is formed on a surface of the first portion during forming the first portion; and wherein the plurality of first cavities is transformed to a plurality of second cavities during forming the second portion, and one of the second cavities includes a first inclined surface and a second inclined surface above the first inclined surface.

Abstract: A method for manufacturing a light-emitting device, comprises steps of: providing an as-cut wafer having an irregularly uneven surface comprising surface roughness greater than 0.5 ?m; and forming a light-emitting stack on the irregularly uneven surface of the as-cut wafer by an epitaxial growth method, and the light-emitting stack comprises an upper surface having surface roughness less than 0.2 nm; wherein there is no patterning or roughing process after the step of providing the as-cut wafer and before the step of forming the light-emitting stack on the irregularly uneven surface of the as-cut wafer.

Abstract: A light-emitting device includes: a light-emitting stack having an upper surface having a first surface roughness less than 0.2 nm; and an as-cut wafer comprising an irregularly uneven surface facing the light-emitting stack and having a second surface roughness greater than 0.5 ?m.

Abstract: A light-emitting device comprises a substrate; a first semiconductor layer formed on the substrate; a light-emitting layer on the first semiconductor layer; and a second semiconductor layer having a rough surface formed on the light-emitting layer, wherein the rough surface comprises a plurality of cavities randomly distributed on the rough surface, and one of the plurality of cavities has a substantially hexagonal shape viewed from top and a curved sidewall viewed from cross-section.