The internal site symmetry of exciton binding traps was investigated. This revealed the presence of Cd vacancy-related defect complexes in Al-, Cl-, I- and In-doped films. Zeeman data on the low-temperature photoluminescence were explained in terms of a modified effective Hamiltonian. From the variation of the line intensities, as a function of the molecular beam epitaxial growth conditions, Cd vacancies were deduced to be constituents of the complexes. A pronounced acoustical phonon replica, and a luminescence that was polarized parallel to a [110] axis, were clear signs of a preferential alignment of the Cd vacancy-related complex centers in the cubic lattice. There was a degradation of the luminescence intensity, of the complex-related lines, as a function of time.

L.Worschech, W.Ossau, F.Fischer, A.Waag, G.Landwehr: Journal of Crystal Growth, 1996, 161, 134-8