Cathodoluminescence and its temperature dependence in Tm-doped Al xGa1-xN thin films

Abstract

Cathodoluminescent (CL) emission from Tm-doped AlxGa 1-xN (AlxGa1-xN:Tm) has been observed with various Al compositions (0 ≤ x ≤ 1). According to CL spectrum from Al 0.81 Ga0.19 N:Tm film 1D2 level-related CL emissions were observed to dominate: the strongest was blue at 464 nm and the next was UV at 369 nm, corresponding to the Tm 1D 2 → 3F4 and 1D2 → 3H6 transitions, respectively. CL luminance increases with Al composition up to x = 0.8, then decreases for AlN:Tm, which is the same as in EL and PL. Luminance value was measured to be 19.4 cd/m 2. The corresponding efficiency was 0.012 lm/W under 5 kV bias and 10 μA current flow. Temperature dependent CL from the Al0.81 Ga 0.19 N:Tm film shows that 1D2 emission increases with temperature up to room temperature (RT) but 1I 6 emission becomes quenched upon approaching RT. © 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.