Speaker
Dr
Balakrishna Avula
(University of The Free State)
Description
Mixed Nitrates of Zn, Eu and Yb were deposited on Si (100) substrates using the sol-gel spin coating method under optimized deposition conditions using monoethanolamine as stabilizing component. This paper reports on the morphology and topographical images of ZnO:Eu3+,Yb3+(7%) thin films. The surface composition of the annealed ZnO films were investigated by using Field emission Scanning Electron Microscopy (FE-SEM) and Time-of-Flight Secondary Ion Mass Spectroscopy (TOF-SIMS). The presence of various types of particles on the surface of the spin coating thin films as well as the differences in the film structure, played an important role to induce artificial topographical effects on the ZnO:Eu3+,Yb3+ thin films. The presence of H on the surface and throughout the entire thickness of the thin films was confirmed by TOF-SIMS. Furthermore, it was found that the near surface region of the as-grown thin films was Zn-rich, and annealing at higher temperatures (1000 °C) removed the H-related defects from the surface of the thin films and affect the balance of the Zn and O concentrations. Both the positive and negative ion depth profiles of the ZnO:Eu3+,Yb3+(7%) thin films were measured. The two and three-dimensional (2D and 3D) images have also been recorded in the positive and negative ion mode. Analysis of the 3D images showed big agglomerated particles on the surface of the Si substrate that appears to be embedded in the substrate and the substrate appears to be on the same level as the particles. This phenomenon was due to the artificial topographic effects which are attributed to the experimental setup of the TOF-SIMS system. The details of these features will be discussed.
Key words: Spin coating, Tof-SIMS, 2D and 3D images.
Supervisor details<br><b>If not a student, type N/A.</b><br>Student abstract submision<br>requires supervisor permission:<br>please give their name,<br> institution and email address.
Prof. H.C. Swart, Department of Physics, University of the Free State, Bloemfontein ZA 9300, South Africa. swarthc@ufs.ac.za
| Consideration for<br>student awards<br><b>Choose one option<br>from those below.</b><br>N/A<br>Hons<br>MSc<br>PhD | PhD |
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Primary author
Dr
Balakrishna Avula
(University of The Free State)
Co-authors
Prof.
H.C. Swart
(University of the Free State)
Prof.
Liza Coetsee
(University of the Free State)
Ms
Mart-Mari Duvenhage
(University of the Free State)
Prof.
O.M. Ntwaeaborwa
(University of the Free State)
