Assignments of the Raman modes of monoclinic erbium oxide

As a heavy rare earth oxide, erbium oxide (Er2O3) has many attractive properties. Monoclinic Er2O3 has useful properties not found in stable cubic Er2O3, such as unique optical properties and high radiation damage tolerance. In this study, cubic Er2O3 coating and Er2O3 coating with mixed phases were prepared. The Raman scattering spectra of these coatings were investigated by using a confocal micro-Raman spectrometer equipped with 325, 473, 514, 532, 633, and 784 nm lasers. A total of 17 first-order Raman modes of monoclinic Er2O3 were identified and assigned. The modes at 83, 112, 152, 170, 278, 290, 409, 446, 478, 521, 603, and 622 cm−1 are of Ag symmetry, whereas modes at 71, 98, 333, 409, 446, and 468 cm−1 are of Bg symmetry. This research provides basic data necessary for the characterization of monoclinic Er2O3 by Raman spectroscopy.