Photoluminescence and Raman Studies of α-MoO3 Doped with Erbium and Neodymium

With the objective of development of optoelectronic devices, nowadays the research in this field is centred around the study of photoluminescence emission of rare earth elements present in the lattice of different oxides. Therefore, in this study we prepared samples of molybdenum trioxide doped with neodymium and erbium at concentrations of 1.0% and 2.0%, using solid state reaction technique from powders of MoO₃, Nd₂O₃ and Er₂O₃. These powders were analysed by X-ray diffraction which determined the presence of phase α-MoO₃. The morphology of the powders was examined using scanning electron microscopy, which showed that the doped samples have regular and well-defined microplates. The absorption UV-spectra revealed that the optical band gap changed slightly (3.2–3.4 eV) with the Er, Nd and Er–Nd concentrations. The photoluminescence shows emission bands at different wavelengths of the visible spectra as a function of the Er, Nd, and Er–Nd doped. The bands were centred at 748 nm and 808 nm transitions of the Nd³⁺ ions respectively. In this region and with excitation wavelength of 350 nm, strong emission lines were not observed for Er. Raman spectroscopy showed typical modes of vibration of α-MoO₃. Major changes have been noted in the case of samples doped with Er at peaks located between 350 cm⁻¹ and 580 cm^–1.