Cathodoluminescence study of GaN doped with Tb

We report the observation of the visible cathodoluminescence (CL) of GaN doped with Tb3+ ions incorporated by implantation. The sharp characteristic emission lines corresponding to Tb3+ transitions are resolved in the spectral range from 350 to 750 nm, and observed over the temperature range of 7–330 K. The luminescence shows transitions which originate in the 5D3 and 5D4 levels and terminate in the 7F manifolds. The depth resolved CL spectra analysis give the luminescence surface dead layer thickness of ∼20 nm. The yellow band starts to grow at 5 keV (corresponding to electron penetration depth ∼219 nm). The time resolved spectra, and rise and decay kinetics are discussed. The decay times for 5D3→7F5 (423.4 nm) and 5D4→7F5 (551.6 nm) transitions at 7 K are ∼0.7 and ∼1.8 ms, with little change with temperature.