This paper reports the observation of truly zero-dimensional excitons of extremely small homogeneous width in highly strained (Zn,Cd)Se/ZnSe quantum-well structures (Cd content >30%, well width ≤3 nm). The occurrence of extra phonon modes not observable on wells of standard design (<20%, >5 nm) indicates structural modifications giving rise to localization sites with sufficiently strong confinement potential. The lifetime of the zero-dimensional excitons ranges between 200 and 250 ps.

• Received 8 July 1996

DOI:https://doi.org/10.1103/PhysRevB.54.R11074