Photoluminescence Properties of Er-Implanted SiO/SiO2 Multilayered Structures with Amorphous or Crystalline Si Nanoclusters

Multi layered SiO/SiO2 structures were prepared by resistive evaporation of silicon monoxide and thermally annealed at 900 degrees C or 1150 degrees C in order to form amorphous or crystalline silicon nanoclusters in SiO2 matrix, respectively. The samples were implanted with Er3+ ions at doses varying from 1.10(14) cm(-2) to 7.10(15) cm(-2) followed by the thermal annealing of implantation defects at 900 degrees C. The Er-implanted structures showed efficient photoluminescence at 1.54 mu m whose intensity and photoluminescence excitation spectra were similar for both structures with crystalline and amorphous Si nanoclusters. The lifetime of the Er-related photoluminescence of low-dose implanted samples with amorphous Si nanoclusters was about 5-6 ms, i.e., significantly longer than for the samples with nanocrystals. It was found that larger Er-implantation doses as well as a post-treatment of the samples in forming gas resulted in a shortening of the Er lifetime. The origin of the sensitization centers, which might be responsible for the excitation of the Er3+ ions in the films with amorphous or crystalline silicon nanoclusters, and possible reasons for the Er-PL lifetime differences in these structures are discussed.