It was recalled that the photoluminescence spectrum of In-doped CdTe was often seen to exhibit a characteristic feature (the so-called W line) at about 12780/cm (1.584eV). Contradictory assignments of this line had been published. Here, by using bulk crystals of In-doped material, it was shown that this feature appeared after heat treatment in a Te atmosphere, together with a decrease in the DoX emission. The Zeeman effect upon the W line was measured, including its dependence upon the directions of the magnetic field and the polarization. The data showed that this line originated from the annihilation of a 2-particle bound exciton which was localized at trigonal complexes with symmetry axes that were parallel to <111> directions. By analyzing level splittings and relative transition probabilities, in terms of a standard spin Hamiltonian, it was found that the trigonal impurity potential was due to a so-called tensional lattice deformation and that the Zeeman spectra could be described quantitatively by the parameters: ge = -1.7, K = 1.08, L = -0.1 and a = 0. Together with the magnitude of the diamagnetic shift, the results showed that, in the bound excitons, the electron orbitals were rather extended and the hole orbitals were rather localized. It was suggested that Ini-VCd, Ini-ACd or Ini-3ACd complexes (where A was a small acceptor impurity such as Li or Na) were the most probable centers giving rise to the W line.

H.Zimmermann, R.Boyn, M.U.Lehr, H.J.Schulz, P.Rudolph, J.T.Kornack: Semiconductor Science and Technology, 1994, 9[9], 1598-603