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摘要
AlxGa1-xN layers with different AlN molar fractions, 0 <= x <= 1, implanted with Tb3+ ions were characterized using structural and optical techniques. After adequate thermal annealing treatments, all the layers evidence the D-5(4)-> F-7(J) intra-4f(8) transitions. The green emission from the D-5(4) emitting level can be identified up to room temperature in samples with x >= 0.53. The preferential population paths of the Tb3+ luminescence were assessed by photoluminescence excitation at RT where two main broad subgap excitation bands peaked at similar to 270 nm and similar to 300 nm were found for the layers with higher aluminium content. The analysis of the temperature-dependent Tb3+ integrated luminescence reveals distinct activation energies for different compositions, with AlN:Tb showing the highest thermal stability for the intraionic luminescence. The ion excitation paths are discussed on a basis of excitonic features and compared with the trend observed for other rare earth ions in nitrides, as well as theoretical predictions. A single exponential decay for the D-5(4)-> F-7(6) transition was measured at RT and the lifetime of the transition was found to increase with increasing composition revealing the sensitivity of the ions to the surrounding medium.
- 出版日期2016-10
