Mollel, Loriku (2026) Atomic Scale Characterisation of Gallium Nanowires on SrTiO3(100). Bachelor's Thesis, Physics.
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Abstract
This thesis presents STM and LEED characterisation of gallium nanowires deposited onto Nb-doped SrTiO3(100) via the cast-and-press method to extend previous AFM-based observations to the atomic scale. The STO(100) was prepared by UHV e-beam annealing and Ar+ sputtering. Sputtering was confirmed to remove the native oxide layer formed upon air exposure and recover a morphology similar to post-annealed images. After gallium deposition, STM imaging revealed a hierarchical morphology: large wire-like formations are internally polycrystalline. On these larger gallium wires, individual nanowires were found. These were resolved, with apparent heights of 6–7 Å and widths of 1.4 ± 0.3 nm, substantially narrower than the 25.0 ± 0.9 nm widths reported by AFM, indicating that previously characterised single nanowires are in fact unresolved bundles of these smaller wires. Lattice measurements at the deposit–substrate boundary yielded a spacing of 2.7 ± 0.2 Å and an inter-vector angle of 88 ± 5°, consistent with either the oxygen sublattice of a TiO2-terminated SrTiO3(100) surface or the (021) plane of metastable beta-Ga; the measured rotation of this lattice relative to the substrate edges lends slightly stronger support to the STO interpretation, while beta-Ga was found to be incompatible with the observed periodicity and symmetry on all low-index planes. These results establish the first STM-resolved structural picture of this system and provide direct input for future experiments.
| Item Type: | Thesis (Bachelor's Thesis) |
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| Supervisor name: | Lo Conte, R. and Ye, J. |
| Degree programme: | Physics |
| Thesis type: | Bachelor's Thesis |
| Language: | English |
| Date Deposited: | 16 Jul 2026 11:51 |
| Last Modified: | 16 Jul 2026 11:51 |
| URI: | https://fse.studenttheses.ub.rug.nl/id/eprint/37421 |
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