Abstract: An epitaxial wafer for an AlGaInP light-emitting device includes a p-type GaAs substrate, a reflection layer in the form of a laminated body of multiple semiconductor layers provided over the substrate, a double hetero-junction light-emitting structure of AlGaInP formed over the reflection layer, the light-emitting structure including an active layer between upper and lower cladding layers, and a current diffusion layer of AlGaAs provided over the double hetero-junction light-emitting structure. The current diffusion layer is transparent to light emitted by the light-emitting structure. The current diffusion layer is n-type AlGaAs, and has a carrier concentration of from 10.sup.17 cm.sup.-3 to 2.times.10.sup.19 cm.sup.-3, and a thickness that is not more than 1 .mu.m.

Abstract: An AlGaInP light-emitting diode includes a double hetero-junction light-emitting structure of (Al.sub.x Ga.sub.1-x).sub.y In.sub.1-y P on a GaAs substrate. A multi-film reflection layer is provided between the GaAs substrate and the double hetero-junction light-emitting structure. The layers forming the double hetero-junction are lattice matched with the GaAs substrate at an epitaxial growth temperature. A GaP current diffusion layer is disposed on the upper surface of the double hetero-junction light-emitting structure, and ohmic electrodes are provided on the underside of the GaAs substrate and on the upper surface of the current diffusion layer.

Abstract: An epitaxial wafer for a light-emitting diode comprises an n-GaAs single crystal substrate on which a Si-doped n-Ga.sub.1-x Al.sub.x As epitaxial layer, a Si-doped p-Ga.sub.1-y Al.sub.y As active layer, and a p-Ga.sub.1-z Al.sub.z As window layer are epitaxially formed, and in which the window/layer has a Si concentration of below 1.times.10.sup.18 cm.sup.-3.