Quantum confined Stark effect in semiconductor quantum wells including valence band mixing and Coulomb effects

摘要

A complete model for evaluating the electro-optic response of a semiconductor quantum well structure is presented. Heavy and light hole mixing in the valence band is included by using a variational technique to determine the basis states. The excitonic effects, which are clearly evident at room temperature in quantum well structures, arise from Coulomb interaction between the charged particles; the corresponding many body problem is treated in the framework of the second quantization approach, by writing the total Hamiltonian of the interacting electron-hole plasma. The electro-optic responses, for both TE (transverse electric) and TM (transverse magnetic) polarized light, are computed by summing up the contributions of all the different transitions; they show a good agreement with experimental results. Some examples of computed electro-optic spectra for GaAs/AlGaAs compounds are presented.