Fabrication and characterization of Er silicates on SiO2/Si substrates

Er silicates have been fabricated on SiO2/Si(100) substrates by the sol-gel method. In contrast to Si(100) substrates, on which the Er2SiO5 phase in general crystallizes, the alpha-Er2Si2O7 with the photoluminescence (PL) main peak at 1531 nm formed at 1200 degrees C. The integrated PL intensity of the alpha-Er2Si2O7 phase was about five to ten times stronger than that of the Er2SiO5 phase, and the alpha-Er2Si2O7 phase showed a relatively long decay time (100-300 mu s) in contrast to several tens of microseconds of the Er2SiO5 phase. Excess O from SiO2 layer may lead to the formation of the alpha-Er2Si2O7 phase.