Magneto-optical determination of the valence-band offset in a CdTe/Cd1-xMnxTe heterostructure

The long-standing problem of valence-hand-offset determination in CdTe/Cd1- xMnxTe heterostructures is reexamined from the point of view of magneto-opt ical methods. We have measured the giant spin splittings of excitonic state s with the magnetic field applied parallel and perpendicular to the growth axis, and the experimental results have been analyzed with a simple analyti cal model which takes into account the special role played by the interface s between the quantum well and the barriers in such systems. The structure studied contained two quantum wells of 20- and 30-Angstrom widths, surround ed by Cd0.875Mn0.125Te barriers. It is shown that the spin splittings of th e hole states confined in the quantum wells are very sensitive to the valen ce-band offset. The simultaneous comparison of experiments and theory for t he two aforementioned geometries yield a precise value of the band offset p arameter Q(upsilon) = 0.40 +/- 0.05. [S0163-1829(99)14815-X].