ASSIGNMENT
Atomic Scale Roughening/Smoothing of metal surfaces by Low Energy Ions
Contact: Dr. Parikshit Phadke (p.phadke@utwente.nl)
Level: BSc
Ion beam-induced surface modifications are at the forefront of modern materials processing. With applications ranging from coating of optics [1], selective layer implantation in silicon [2] and large area nano-structuring for functional surfaces [3]. In all such applications, the impact of ions into subsurface regions leads to rearrangement of surface atoms causing roughening or smoothing effects governed by the interaction’s geometry. In certain geometries, ripple formations have also been reported.
Understanding of the surface rearrangements is crucial for control of surface structure and properties for technological applications requiring large area nanostructures/smoothness. Models and experiments usually discuss the impact of ions at non-normal incidence at high energies (>keV), or near-normal incidence at low energies (< 500eV) and elevated temperatures [4]. Additionally, the impact of chemical interactions are generally neglected. These aspects are essential for ion-assisted depositions or surface functionalization.
This project aims to separate the chemical and physical aspects of surface restructuring upon ion irradiation for metal films at normal incidence using ions of reactive and inert gas species with similar energy transfer parameters. The student will have hands-on experience with ion beam exposure facilities and roughness characterization with atomic force microscopy and is expected to actively participate in interpretation of the physical mechanisms of ion induced morphology changes.
[1] Thin Solid Films 410(2002)86–93
[2] Surf. Interface Anal.2008,40, 1415–1422
[3] Materials Science and Engineering C 23 (2003) 201–209
[4] Phys. Rev. B 72, 235310