Abstract: A light-emitting device includes a semiconductor epitaxial structure that has a first surface and a second surface opposite to the first surface. The semiconductor epitaxial structure includes a first-type semiconductor layered unit, an active layer, and a second-type semiconductor layered unit sequentially disposed in such order in a direction from the first surface to the second surface. The active layer includes quantum well layers and quantum barrier layers stacked alternately, each of the quantum well layers includes a material that is represented by InxGa1-xAs, and each of the quantum barrier layers includes a material that is represented by GaAs1-yPy, where 0.2?x?0.3, and 0?y?y0.05.

Abstract: A light-emitting diode includes a semiconductor epitaxial structure that has a first current spreading layer, a first transition layer, a first cladding layer, a second transition layer, a first confinement layer, an active layer, a second confinement layer, a second cladding layer, and a second current spreading layer. The first current spreading layer, the first cladding layer, and the first confinement layer independently have semiconductor materials that are different in an aluminum content. An aluminum content of the first transition layer increases in a direction from the first current spreading layer to the first cladding layer. An aluminum content of the second transition layer decreases in a direction from the first cladding layer to the first confinement layer.

Abstract: A light-emitting device includes a semiconductor epitaxial structure that has a first surface and a second surface, and that includes a first current spreading layer, a Inx1Ga1-x1As layer, a first cladding layer, an active layer and a second cladding layer disposed sequentially in such order from the first surface to the second surface, wherein, in the Inx1Ga1-x1As layer, 0<x1?0.08. In another aspect of the disclosure, the first current spreading layer is made of gallium arsenide, and has a thickness ranging from 2 ?m to 10 ?m and a doping concentration ranging from 1E17/cm3 to 4E18/cm3. In yet another aspect of the disclosure, a layered stack is disposed between the first current spreading layer and the first cladding layer, and includes an Inx3Ga1-x3As layer and an Aly3Ga1-y3AszP1-z layer, in which 0.02<x3?0.20, 0?y3?0.25, and 0.7<z?0.95.

Abstract: A light-emitting epitaxial structure includes an n-type ohmic contact layer, an n-type cladding layer, a light emitting layer, a p-type cladding layer, a p-type GaInP transition layer, a p-type AlxGa(1-x)InP transition unit and a p-type GaP ohmic contact layer that are sequentially disposed in such order, wherein in the p-type AlxGa(1-x)InP transition unit, 0<x?0.7. An infrared light-emitting diode including the aforementioned light-emitting epitaxial structure and a method for manufacturing the light-emitting epitaxial structure are also disclosed.