Multiple phase production on doping Er3+ into α-Al2O3

Samples of α-Al2O3 were prepared by the preformed sol or nitrate–citrate methods and were doped with Er3+ at concentrations from 25 to 0.1 at.%. The luminescence spectra showed the formation of erbium garnet and/or perovskite compounds and no luminescence from Er3+ substituted at Al3+ sites was detected. This contrasts with previous reports, especially the low-temperature luminescence of α-Al2O3:Er3+ (1 at.%) which in fact corresponds to ErAlO3.