| AVS 58th Annual International Symposium and Exhibition | |
| Thin Film Division | Monday Sessions |
| Session TF-MoM |
| Session: | Thin Films: Growth and Characterization I |
| Presenter: | Rama Sesha Vemuri, The University of Texas at El Paso |
| Authors: | R.S. Vemuri, The University of Texas at El Paso T. Varga, Pacific Northwest National Laboratory S.V. Shutthanadan, Pacific Northwest National Laboratory S.V.N.T. Kuchibhatla, Pacific Northwest National Laboratory M.H. Engelhard, Pacific Northwest National Laboratory P. Nachimuthu, Pacific Northwest National Laboratory C.H. Henager, Pacific Northwest National Laboratory C.M. Wang, Pacific Northwest National Laboratory S. Thevuthasan, Pacific Northwest National Laboratory C.V. Ramana, The University of Texas at El Paso |
| Correspondent: | Click to Email |
There has been growing interest in thin bi-metallic multilayer films for the usage under extreme radiation conditions because of their radiation healing properties. Recent discovery and research indicate that materials can be hardened against radiation damage by building nanolayered structures with an optimized layer thickness to increase point defect recombination relative to a non-layered structure and that can self-heal. In this study, we investigate whether the internal interfaces can be manipulated at the nanoscale to enhance dynamic recombination of radiation-produced defects, or self-healing, so as to dramatically reduce radiation damage without compromising other properties using Ti/Al multilayer films.
Ti/Al multilayer films were fabricated on Si (100) and epi polished MgO (100) substrates using DC magnetron sputtering and Molecular beam epitaxy (MBE) The growth parameters for each method, for sputtering – pressure, power and substrate temperature deposition rate; and for MBE- deposition rate and substrate temperature were optimized to achieve high-quality thin films. The films were characterized using x-ray diffraction (XRD), x-ray reflectivity (XRR), Rutherford backscattering spectrometry (RBS), and x-ray photoelectron spectroscopy (XPS) measurements. The films show mostly polycrystalline structure with no elemental interdiffusion at the interfaces. Detailed structural and compositional analysis was also performed using high resolution TEM/STEM and atom probe tomography (APT). The films were irradiated using 1-8 MeV Au ions to understand the radiation effects. The damage peak, stopping range and ion distribution were simulated using binary collision approximation based Monte Carlo method (SRIM software program). Au ion energies, estimated from the simulation, were used to position the damage peak at the interested interfaces and away from the interfaces to obtain the complete picture at the interfaces and in the bulk of the films. The interface and crystal lattice damage, amorphization, and defect density were studied by RBS, HAADF-STEM and APT, and compared with those results from the pristine samples. The relationships between film properties and radiation healing characteristics will be presented and discussed.