Enhanced blue emission from Tm-doped AlxGa1-xN electroluminescent thin films

Electroluminescent (EL) emission from Tm-doped AlxGa1-xN (AlxGa1-xN:Tm) has been observed with various Al compositions (0less than or equal toxless than or equal to1). AlxGa1-xN:Tm thin films were grown by molecular beam epitaxy with in situ doping of Tm. At lower Al composition (x<0.15), blue emission at 478 nm dominates, corresponding to the Tm (1)G(4)-->H-3(6) transition. For x>0.15, however, a second blue emission peak was observed at 465 nm, becoming dominant with increasing Al composition. The 465 nm emission is attributed to the higher level Tm transition D-1(2)-->F-3(4), which was not observed in GaN:Tm. Blue EL emission from Tm was enhanced with Al content in the films. The ratio of EL intensity at blue (465 nm plus 478 nm) to infrared (801 nm) wavelengths increased monotonically with Al composition, from similar to2 for GaN:Tm to similar to30 for AlN:Tm. (C) 2003 American Institute of Physics.