Growth-temperature dependence of Er-doped GaN luminescent thin films

Visible photoluminescence (PL) and electroluminescence (EL) emission has been observed from Er-doped GaN thin films grown on (111) Si at various temperatures from 100 to 750degreesC in a radio-frequency plasma molecular beam epitaxy system. PL and EL intensities of green emission at 537 nm from GaN:Er films exhibited strong dependence on the growth temperature, with a maximum at 600degreesC. Scanning electron and atomic force microscopy showed smooth surfaces at 600degreesC and rough surfaces at 100 and 750degreesC. X-ray diffraction indicated that the GaN:Er film structure was oriented with the c axis perpendicular to the substrate for all growth temperatures. The crystalline quality initially improves with an increase in growth temperature, and saturates at similar to500degreesC. Considering both the luminescence and structural properties of the film, similar to600degreesC seems to be the optimal temperature for growth of Er-doped GaN luminescent films on Si substrates. (C) 2002 American Institute of Physics.