Cadmium vacancy related defects in MBE grown CdTe

The internal site symmetry of exciton binding traps and the local structure are investigated revealing cadmium vacancy related defect complexes in aluminum-, chlorine-, iodine- and indium-doped CdTe films. The Zeeman experiments on the low temperature photoluminescence are discussed in terms of a modified effective Hamiltonian. The corresponding g-factor of the electron and the hole parameters K and L have been determined. From the studies of line intensities associated with the defect complexes as a function of the MBE growth conditions, cadmium vacancies are identified as constituents of these complex defects. The proposed microscopic models are compared with the observed properties of the bound exciton recombinations. Pronounced acoustical phonon replica and luminescence polarized parallel to a [110] axis are obviously evidences for a preferential alignment of the Cd vacancy related complex centers in the cubic CdTe lattice. A degradation of the luminescence intensity of complex associated lines with time has been detected.