| AVS 66th International Symposium & Exhibition | |
| Actinides and Rare Earths Focus Topic | Monday Sessions |
| Session AC+LS+MI-MoM |
| Session: | Magnetism, Complexity, Superconductivity, and Electron Correlations in the Actinides and Rare Earths |
| Presenter: | Mohammed Bsatee, Ohio University |
| Authors: | W.M. Jadwisienczak, Ohio University M. Bsatee, Ohio University F.P.N. Inbanathan, Ohio University R. Martínez, University of Puerto Rico H. Huhtinen, University of Turku, Finland R. Palai, University of Puerto Rico |
| Correspondent: | Click to Email |
There have been ongoing efforts in developing rare earth (RE) ions doped semiconductors responsive to optical and magnetic stimuli for developing multifunctional devices. ZnO is considered as a promising semiconductor with wide range of applications in optoelectronics and spintronics due to its optical properties (i.e. direct band gap, high electron mobility, high thermal stability, strong absorption of UV), and at the same time being an attractive host for RE doping resulting in enhanced spin polarization in ZnO:RE matrix [1]. In this project, undoped and RE ions (Er and Yb) doped and co-doped ZnO:Na nanoparticles were studied with an aim to understand recently reported magnetodielectric and photodielectric effects stimulated by magnetic field and UV excitation stimuli [2]. After synthesizing well-defined Er and Yb-co-doped ZnO:Na by sol-gel route, evaluation of structural, optical, magnetic and electrical characteristics of synthesized nanoparticles was performed. Structure, morphology, and composition of the samples were analyzed by XRD and SEM showing high quality hexagonal crystal structure. The absence of secondary phases was confirmed by Raman spectroscopy and XPS analysis of all elements in ZnO:NaErYb compound. Optical properties were investigated by optical reflectance spectroscopy, photoluminescence (PL), PL excitation, and PL kinetics with photons excitation energy corresponding to above and below bandgap energy. PL spectra were investigated under magnetic field of up to 2 Tesla in 7 K – 400 K temperature range. It was observed that PL spectra exhibit broad green-yellow defects emission band without NBE excitonic peak. PLE spectra revealed that both Er3+ and Yb3+ ions are optically active and involved in complex energy transfer between ZnO:Na host and 4f-shall levels of RE3+ ions dopants. PL spectra show features related to intra-shell 4f-4f transitions of the Er3+ ion (at 522 nm) and Yb3+ ion (at 980 nm). It was observed that luminescence decay of the ZnO defect band is unexpectedly long (> tens of 10-3 second), strongly affected by RE3+ ions doping and depends on the magnetic field strength when excited at 3.814 eV. In the presentation we will attempt to correlate reported magnetodielectric and photodielectric properties of the Er,Yb-co-doped ZnO:Na [2] with observed optical characteristics.
References
[1] A.G. El Hachimi, H. Zaari, A. Benyoussef, M. El Yadari, A. El Kenz, J. Rare Earths, 32, p.715 (2014).[2] R. Martinez Valdes, N. Kumar, H. Huhtinen, W. M. Jadwisienczak, R Palai, MRS Adv. (2019), DOI: 10.1557/adv.2019. 66.