Room-temperature-grown rare-earth-doped GaN luminescent thin films

Visible emission has been observed from rare-earth (RE)-doped GaN electrolu minescent devices (ELDs) as-grown near room temperature on Si (50-100 degre esC): red from GaN:Eu, green from GaN:Er, and blue from GaN:Tm. Green emiss ion at 537/558 nm from GaN:Er ELD had a measured brightness of similar to 2 30 cd/m(2) at 46 V bias. X-ray diffraction indicates that the low-temperatu re-grown GaN:Er structure was oriented with the c axis perpendicular to the substrate. Scanning electron and atomic force microscopy indicate that the films had a rough surface and a compact structure consisting of small grai ns. Electroluminescence intensity of GaN:RE was significantly improved with postgrowth annealing. For GaN:Er films, after 800 degreesC annealing, the green emission brightness efficiency increased by similar to 10x. (C) 2001 American Institute of Physics.