Comment on 'Enhancement in hardness and transmittance of ZnS via SiO2/Y2O3 multilayer'

In a recent paper [1], Huayu Zhang et al. reported data on the enhancement in hardness and transmittance of ZnS via SiO2/Y2O3 multilayer. In particular, the authors discussed the chemical state of sputtered Y2O3 on SiO2/ZnS measured by X-ray photoelectron spectroscopy. We suggested that the split spectrum of Y 3d doublet should be decomposed into the sum of the doublet and the exact notation of O 1s level should be applied. The O 1s of 528.8 eV could also be assigned to Y2O3 and the O 1s of 531.5 eV could be assigned to Si related compound. (C) 2015 Elsevier B.V. All rights reserved.