Influence of Annealing Temperature and Time on the Photoluminescence and the Structure of Y2O3:Eu Thin Films

Y2O3:Eu thin films were deposited on p-type (100)-oriented silicon wafers by using the radiofrequency (RF) magnetron sputter deposition technique and then post-annealed in an air ambient at various temperatures and holding times. X-ray diffraction data showed that the as-deposited films had a cubic Y2O3 structure textured with the (222) plane. The as-deposited films were found to be under internal compressive stress, and the annealing treatment led to relaxation of the stress in the films. Photoluminescence (PL) was observed from the films annealed at temperatures >= 400 degrees C, and the strongest peak occurred at 613 nm in the red range. The PL intensity increased as the annealing temperature was increased, resulting from the improved crystalline quality of the Y2O3:Eu films annealed at higher temperatures. The PL intensity reached a maximum at 1200 degrees C and then decreased due to the formation of the Y2SiO5 phase. The Y2O3:Eu films were also annealed at 1200 degrees C for different periods of time from 1 to 10 h. The PL intensity of the 1200 degrees C-annealed films was decreased for longer holding time resulting from the formation of the Y2SiO5 phase.