Abstract: A semiconductor device having a reflecting layer consisting of unit semiconductors each consisting of two or more semiconductor films of different compositions. The thickness of the unit semiconductors varies continuously or in steps in the direction of thickness of the reflecting layer, preferably decreases in the direction toward the light incidence surface of the layer. For example, the reflecting layer has a varying-thickness portion whose unit semiconductors have a continuously varying thickness, and may include an iso-thickness portion whose semiconductors have the same thickness. The composition at the interface of the adjacent films preferably changes to mitigate a lattice mismatch which causes crystal defects of the layer.

Abstract: A light-emitting diode having a light-generating layer for generating an electromagnetic radiation by electroluminescence, a light-emitting surface through which the radiation is emitted, and a light-reflecting layer remote from the light-emitting surface, for reflecting a portion of the radiation toward the light-generating layer so that the radiation reflected by the light-reflecting layer is also emitted through the light-emitting surface. The light-reflecting layer consists of two or more interference type reflecting layers which include one or more reflecting layers each capable of most efficiently reflecting a wave whose wavelength is longer than the nominal wavelength of the radiation. The light-emitting surface may have irregularity for irregularly reflecting the radiation, or an anti-reflection layer formed thereon by deposition.