Photoluminescence of Er-doped Si-SiO2 and Al–Si-SiO2 sputtered thin films

Er-doped Si-SiO2 and Al–Si-SiO2 films have been deposited by rf-sputtering being annealed afterwards. Annealing behavior of the Er3+: 4I13/2→4I15/2 emission of Er-doped Si-SiO2 yields a maximum intensity for annealing at 700–800 °C. 4I13/2→4I15/2 peak emission for Er-doped Al–Si-SiO2 at 1525 nm is shifted from that for Er-doped Si-SiO2 at 1530 nm and the bandwidth increases from 29 to 42 nm. 4I13/2→4I15/2 emission decays present a fast decaying component related to Er ions coupled to Si nanoparticles, defects, or other ions, and a slow decaying component related to isolated Er ions. Excitation wavelength dependence and excitation power dependence for the 4I13/2→4I15/2 emission correspond with energy transfer from Si nanoparticles. Populating of the 4I11/2 level in Er-doped Si-SiO2 involves branching and energy transfer upconversion involving two or more Er ions. Addition of Al reduces the populating of this level to an energy transfer upconversion involving two ions.