Optical investigation of hole and electron subbands in HgTe-CdTe superlattices

Photoluminescence spectroscopy and resonant Raman scattering were applied to investigate electronic properties of HgTe-CdTe superlattices. It is established that the spin-orbit split-off valence states in the CdTe layers are quantized and that the small band offset the lifetime of the holes. Radiative recombinations form electron subbands in the HgTe square wells can be measured when the subband energies are close to the conduction-band edge of CdTe. The spectra suggest that relaxation processes in the HgTe subbands involve the emission of optical phonons.