Patent attributes
The present invention pertains to a unipolar quantum cascade laser consisting of several semiconductor multilayer structures (C) that are layered behind one another between two electrodes in a periodic sequence such that an active area (A) and a transitional or injection area (B) respectively alternate. The active areas (A) respectively have at least one upper and one lower energy level for electrons, between which electron transitions (T) emitting light take place. The transitional or injection areas (B) are realized in such a way that they allow the electron transport from the lower energy level of the preceding active area referred to the transport direction into the upper energy level of the following active area referred to the transport direction. In this laser, the active areas (A) comprise at least one quaternary material layer as barrier layer and are realized in such a way that the highest and the second highest local maximum of the square of the quantum-mechanical wave function for the electrons in the upper energy level differ by less than 50%.
