Abstract: In accordance with the present invention, GaAs-based optoelectronic devices have an active region that includes a well layer composed of a compressively-strained semiconductor that is free, or substantially free, of nitrogen disposed between two barrier layers composed of a nitrogen- and indium-containing semiconductor.

Abstract: An intersubband quantum cascade laser structure includes multiple coupled laser stages, wherein each stage has a multilayer structure including an electron injector, an active region with at least one quantum well, and an electron reflector. Electrons injected from the injector into the active region at a high energy level relax to a lower energy level with the emission of a photon at, for example, mid-infrared wavelengths. The reflector reflects electrons at the higher energy level at which they were injected and transmits electrons from the lower energy level after emission of a photon. Multiple layers of semiconductor are formed on each side of the multistage structure to provide conduction across the device and to provide optical confinement of the photons emitted.

Abstract: A semiconductor laser and light emitting device is defined. The device comprises an electron injector and an active region adjacent to the electron injector. The active region includes at least one deep quantum well with barrier layers adjacent to either side of the quantum well or wells such that electrons injected from the electron injector into a high energy level of the quantum well relax to a lower energy level with the emission of a photon and are transmitted out to a region beyond the last barrier layer of the active region. The electron injector includes quantum well layers. The bottom of each deep quantum well or wells in the active region is lower in energy than the bottoms of the quantum well layers in the electron injector. The device may further comprise at least two stages wherein each stage contains an electron injector and an active region.

Abstract: Semiconductor optoelectronic devices such as diode lasers are formed on InP substrates with an active region with an InAsN or InGaAsN electron quantum well layer and a GaAsSb or InGaAsSb hole quantum well layer which form a type II quantum well. The active region may be incorporated in various devices to provide light emission at relatively long wavelengths, including light emitting diodes, amplifiers, surface emitting lasers and edge-emitting lasers.