Successful application of the 8-band k·p theory to optical properties of highly strained In(Ga)As/InGaAs quantum wells with strong conduction-valence band coupling

Band-edge optical properties of highly strained In(Ga)As/InGaAs quantum wells on InP with the bandgap wavelength longer than 2 μm are analyzed by using 6- and 8-band k·p theory. It is demonstrated that the 8-band model is indispensable for the analysis of highly strained In(Ga)As/InGaAs quantum wells due to the strong coupling between conduction and valence bands induced by large strain in the well. Furthermore, an energy correction originating from the interaction between the spin-orbit coupling and the strain, which has been discarded in conventional k·p theory, is taken into account, and the role of the effect for highly strained quantum wells is discussed. The photoluminescence peak wavelength and absorption spectra of In(Ga)As/InGaAs quantum wells calculated by 8-band model are in excellent agreement with those obtained by experiment, showing the validity of the results presented here.