Energy transfer mechanism between terbium and europium ions in zinc oxide and zinc silicates thin films

The aim of this study is to enhance europium ions emission by energy transfer mechanism from terbium to europiumionsin codoped ZnO thin films. The samples were annealedwith classical and rapid thermal anneal treatmentsfor different temperatures (973 K, 1173 K and 1373 K). Codoped ZnO thin films were characterized fortheir chemical, structural and photoluminescence properties. Two different terbium concentrations have beenstudied with roughly constant europium content. Terbium and europium codoping allows an energy transferfrom trivalent terbium to europium ions leading to the europium emission hardly observed for ZnO thin filmsdoped by europium only. With thermal annealing above 1173 K, diffusion processes occurred with silicon substrateto form zinc silicate and rare earth oxide with a concomitant photoluminescence signal from trivalent europiumions at 615 nm (5D0 → 7F2 transition).