GaAsSb layer with graded composition reducing stress in InAs/GaAs quantum dots

摘要

In the present invention, there is disclosed a multilayer semiconductor epitaxial structure with InAs/GaAs quantum dots and GaAsSb cover and stress reducing layer maintaining heterotransition of the type I between InAs quantum dot and GaAsSb layer and enabling emission of electroluminescences on a telecommunication wavelength of 1300 nm. The maintenance of the heterotransition of the type I for this wavelength is achieved by graded composition of the GaAsi1-xSbix layer such that immediately close to the quantum dots in the GaAsSb layer, the concentration of the Sb (x=0.03 through 0.09) is lower (to thereby ensure sufficient barrier for holes in the InAs quantum dots and their localization within the quantum dots), while in the direction to the epitaxial growth the antimony concentration in the GaAsSb increases to the maximum concentration, which is in the range of x=0.15 through 0.30. (By this, the necessary relief of stress inside the quantum dots and prolongation of the emitted wavelength is achieved). The structure can be implemented with a continuous or graded change in antimony concentration by means of two or more layers.