Mechanism of enhanced photoluminescence of Tb ions in hydrogenated silicon-rich silicon oxide films

Abstract Terbium-doped silicon-rich silicon oxide films were deposited and hydrogenated at elevated temperatures. The influence of hydrogenation on defects-mediated non-radiative recombination of excited Tb 3+ ions was investigated by means of photoluminescence and photoluminescence decay measurements. An increase in photoluminescence intensity and photoluminescence decay time was observed upon hydrogenation for the main 5 D 4 – 7 F 5 transition of Tb 3+ ions. This observation was ascribed to saturation of non-radiative recombination defect centers with hydrogen. It was found that the number of emitted photons increases upon passivation as a result of two effects: (1) a reduction of the non-radiative recombination rate, and (2) optical activation of new Tb 3+ emitters. Based on the obtained results and literature data, Forster energy-transfer was suggested as the interaction responsible for the non-radiative coupling between Tb 3+ ions and defects.