Near 10 μm intervalence subband optical transitions in p-type In 0.49Ga0.51P-GaAs quantum well structures

In this paper, the intervalence subband optical transitions in p-doped In_0.49Ga_0.51P-GaAs quantum well structures are theoretically investigated. The intervalence subband optical transitions are modelled by the multiband effective mass equations incorporating the unitary transformation numerical method. The present formalism is based on the k&oarr;·P&oarr; perturbation theory as done to date but contains two significant improvements: 1) a more efficient treatment of band structures, optical matrix elements, and absorption coefficients; and 2) the avoidance of zero-order Bloch function approximation for calculating the intervalence subband optical matrix elements and absorption spectra in favour of correcting the first-order perturbation theory in order to take the remote band effects into account. Both of the requirements, especially the latter, play a very important role in gaining qualitative insight and obtaining quantitative calculation of optical selection rules. A systematical study of the subband structures, intervalence subband optical matrix elements, and absorption spectra is made for p-doped In_0.49Ga _0.51P-GaAs quantum wells, and a design guideline for near 10 μm infrared absorption is also discussed