Abstract: Radiation occurs when current is injected into an active layer from electrodes. A pair of clad layers is disposed sandwiching the active layer, the clad layer having a band gap wider than a band gap of the active layer. An optical absorption layer is disposed outside at least one clad layer of the pair of clad layers. The optical absorption layer has a band gap wider than the band gap of the active layer and narrower than the band gap of the clad layer. A spread of a spectrum of radiated light can be narrowed.

Abstract: The principal surface of a substrate made of a group III-V compound semiconductor material is about a (100) plane. A light emitting lamination structure is disposed on the principal surface. In the light emitting lamination structure, a quantum well layer is sandwiched by a pair of carrier confinement layers made of a semiconductor material having a band gap wider than a semiconductor material of the quantum well layer. The pair of carrier confinement layers are sandwiched by a pair of clad layers made of a semiconductor material having a band gap wider than the band gap of the semiconductor material of the carrier confinement layers. Thicknesses of the quantum well layer and the carrier confinement layers, as well as compositions of the semiconductor materials thereof, are set such that light emission recombination of electrons and holes occurs in the quantum well layer and not in the carrier confinement layers.

Abstract: A luminescence structure is formed on a substrate made of semiconductor or insulator. The luminescence structure has a lamination structure that an active layer made of semiconductor is sandwiched between a pair of clad layers made of semiconductor. The clad layer is made of the semiconductor having a band gap wider than an energy corresponding to a peak wavelength of an EL spectrum of the active layer. A carrier trap layer is disposed between the substrate and luminescence structure. A peak wavelength of an EL spectrum of the carrier trap layer is longer than a wavelength corresponding to a band gap of the substrate and the peak wavelength of the EL spectrum of the active layer. Electrodes are formed to inject current into the active layer.

Abstract: Radiation occurs when current is injected into an active layer from electrodes. A pair of clad layers is disposed sandwiching the active layer, the clad layer having a band gap wider than a band gap of the active layer. An optical absorption layer is disposed outside at least one clad layer of the pair of clad layers. The optical absorption layer has a band gap wider than the band gap of the active layer and narrower than the band gap of the clad layer. A spread of a spectrum of radiated light can be narrowed.

Abstract: The principal surface of a substrate made of a group III-V compound semiconductor material is about a (100) plane. A light emitting lamination structure is disposed on the principal surface. In the light emitting lamination structure, a quantum well layer is sandwiched by a pair of carrier confinement layers made of a semiconductor material having a band gap wider than a semiconductor material of the quantum well layer. The pair of carrier confinement layers are sandwiched by a pair of clad layers made of a semiconductor material having a band gap wider than the band gap of the semiconductor material of the carrier confinement layers. Thicknesses of the quantum well layer and the carrier confinement layers, as well as compositions of the semiconductor materials thereof, are set such that light emission recombination of electrons and holes occurs in the quantum well layer and not in the carrier confinement layers.

Abstract: The principal surface of a substrate made of group III-V compound semiconductor is about (100) plane. A light emitting lamination structure is disposed on the principal surface. The light emitting lamination structure includes a quantum well layer made of group III-V mixed crystal semiconductor containing In, a pair of carrier confinement layers made of semiconductor material having a band gap wider than the quantum well layer and sandwiching the quantum well layer, and a pair of clad layers made of semiconductor material having a band gap wider than the carrier confinement layers and sandwiching the quantum well layer and the carrier confinement layers. A difference of 100 meV or larger exists between an energy level of the carrier confinement layers at a conduction band lower end and a ground level of an electron in the quantum well layer.

Abstract: The principal surface of a substrate made of group III-V compound semiconductor is about (100) plane. A light emitting lamination structure is disposed on the principal surface. The light emitting lamination structure includes a quantum well layer made of group III-V mixed crystal semiconductor containing In, a pair of carrier confinement layers made of semiconductor material having a band gap wider than the quantum well layer and sandwiching the quantum well layer, and a pair of clad layers made of semiconductor material having a band gap wider than the carrier confinement layers and sandwiching the quantum well layer and the carrier confinement layers. A difference of 100 meV or larger exists between an energy level of the carrier confinement layers at a conduction band lower end and a ground level of an electron in the quantum well layer.

Abstract: A substrate has first and second edges disposed in parallel and a principal surface connecting the first and second edges. An active layer is formed on the principal surface. A ridge-like region is disposed on the active layer along a path interconnecting a point on the first edge and a point on the second edge. The ridge-like region is made of semiconductor material having a refraction index smaller than a refraction index of the active layer, and defines a waveguide. The path is disposed along the principal surface and includes a first region on the side of the first edge and a second region on the side of the second edge. A first angle is taken between a normal to the first edge directing toward the principal surface and the first region. A second angle smaller than the first angle is taken between a normal to the second edge directing toward the principal surface and the second region. Electrodes inject current in a region of the active layer along the path.

Abstract: A substrate has first and second edges disposed in parallel and a principal surface connecting the first and second edges. An active layer is formed on the principal surface. A ridge-like region is disposed on the active layer along a path interconnecting a point on the first edge and a point on the second edge. The ridge-like region is made of semiconductor material having a refraction index smaller than a refraction index of the active layer, and defines a waveguide. The path is disposed along the principal surface and includes a first region on the side of the first edge and a second region on the side of the second edge. A first angle is taken between a normal to the first edge directing toward the principal surface and the first region. A second angle smaller than the first angle is taken between a normal to the second edge directing toward the principal surface and the second region. Electrodes inject current in a region of the active layer along the path.