Growth and study of Tb3+ doped Nb2O5 thin films by radiofrequency magnetron sputtering: Photoluminescence properties

Undoped and doped Nb2O5 thin films were successfully deposited on silicon wafer by sputtering technique from high purity Nb2O5 and Tb4O7 targets and annealed by rapid thermal annealing between 400 degrees C and 900 degrees C. Chemical and structural investigations of undoped and Tb-doped Nb2O5 films were made, leading to the determination of stoichiometry and identification of phase transformations with increasing annealing temperature and Tb3+ ion content. The optical properties' analysis (spectrophotometry UV-Vis-NIR, spectroscopic ellipsometry) of those undoped and doped Nb2O5 films led us to the determination of refractive index and electronic properties evolution with annealing temperature and Tb3+ ion content. The structural evolution was confirmed by analysis of Raman spectra of undoped and doped Nb2O5 films. The photoluminescence properties of Tb3+ ion-doped Nb2O5 thin films were also studied. The correlation between the photoluminescence of Tb3+ ion and the electronic properties of the Nb2O5 host matrix is highlighted. The relationship between the structural modifications, the electronic properties of the host matrix, and the photoluminescence of Tb3+ ion is established.