Effect of non-stoichiometry on the occurrence of Er3+ luminescence sites in erbium-implanted zinc selenide

Erbium-implanted ZnSe cubic crystals with a high zinc vacancies (Vzn) concentration gave luminescence due to Er3+ ions at Znsub(sub) sites (Centre C) but no luminescence due to Er3+ ions at Znsub(int) sites (Centre A) or Sesub(sub) sites (Centre B). On the other hand, Centres A and B were detected in samples with low Vsub(Zn) concentrations but Centre C was absent. To detect luminescence due to all three erbium centres moderate Vsub(Zn) concentrations were necessary. In such samples post-implantation annealing at 250-3250C caused Er3+ ions to occupy Sesub(sub) and Znsub(int) sites but annealing at 4000C caused Er3+ ions to migrate from the Sesub(sub) sites and be detected at Znsub(sub) sites. (author)