The problem of calculating the valencehyphen;band structure of strainedhyphen;layer quantum wells in the effectivehyphen;mass approximation is reviewed. Using the spherical approximation and exploiting the simplicity of the infinitely deep well model we show that the inhyphen;plane effective mass is determined by two factorsmdash;a splitting contribution which is dominant at large strains, and a quantum confinement contribution. A model for finitehyphen;depth wells is presented which gives analytic expressions for the zonehyphen;center inhyphen;plane mass and associated nonparabolicity factor, and it is applied to the system InxGa1minus;xAs/GaAs. The model allows the computation of valencehyphen;band structure using no more than a pocket calculator. It is shown to give results in reasonable agreement with experiment.
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