Optical and magnetic properties of (Er, F) co-doped SnO2 nanocrystals

Uniformly (Er, F) co-doped SnO2 nanocrystals, obtained by a low-temperature solution-based method, were characterized by a variety of analytical techniques. The structure, morphology, and ratio of the elements were con firmed by PXRD, SEM, and TEM analysis, respectively. From XPS analysis, atomic concentrations of Sn, O, and F were quanti fied. Interparticle pore size increased significantly (with a mean pore diameter of 25.82 nm) in the codoped sample. Higher in-plane oxygen vacancies and bands due to multiphonon scattering were observed in the Raman spectrum of the sample. The defect traps in the sample were experimentally determined using TL spectroscopy. A broad intense glow curve at 485 K and a weak emission at 600 K in the TL spectrum were quenched on exposure to UV radiation. A large blue shift of the exciton absorption (due to the Moss-Burstein effect) and sharp bands due to intraconfigurational f-f transitions were observed for (Er, F) co-doped SnO2 with an estimated band gap of 4.18 eV. From the photoluminescence spectral studies, 3 types of emission centers at 471 nm, 546 nm, and 627 nm were detected. Co-doping stabilized ferromagnetism in SnO2 at room temperature.