Reconstruction of excitonic spectrum during annealing of ZnSe : N grown bymetalorganic vapor phase epitaxy

The reconstruction of the bound excitonic spectra of MOVPE-grown ZnSe:N sam ples caused by thermal annealing was observed. The results of the low tempe rature photoluminescence, reflection and SIMS measurements show that this r econstruction is caused neither by the strain effect nor by the removal of hydrogen from the samples. The calculation of the defect structure and ener gy by the SCF MO LCAO method was carried out, and a new stable configuratio n of the N-se center has been found. A model of reconstruction of the nitro gen centers is proposed, assuming that the transition of N-Se centers from a less stable state with distorted T-d configuration into the energetically more favorable distorted C-3v configuration occurs due to thermal annealin g, resulting in the corresponding changes in the luminescence spectra.