Boer, Jouke, de (2026) Exfoliation of PtBi2, Pt(BiTe)2, and PtTe2 on Ag(111)/mica in UHV, Alongside Chamber Optimization. Master's Thesis / Essay, Applied Physics.
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Abstract
This research aims to address the challenge of reliably producing large, high-quality monolayer crystals of topological materials, as traditional exfoliation methods are limited by low yield, contamination, and poor substrate adhesion. In pursuit of this objective, the effectiveness of ultra-high vacuum (UHV) kinetic in situ single-layer synthesis (KISS) exfoliation of PtBi2, Pt(BiTe)2, and PtTe2 on annealed and sputtered Ag(111)/mica was evaluated. The characteristic properties of the exfoliated crystals were analyzed using optical microscopy, atomic force microscopy (AFM), low-energy electron diffraction (LEED), and X-ray photoelectron spectroscopy (XPS). Via optical microscopy, the surface area of the exfoliated PtBi2 crystals was determined to be the largest, whereas the PtTe2 flakes exhibited the smallest surface area. AFM measurements confirmed that the crystal thicknesses are consistent with monolayer values. Furthermore, LEED analysis verified the presence of an exfoliated Pt(BiTe)2 flake, with its domain rotated 26.06 ± 0.08◦ with respect to the Ag(111)/mica. Lastly, XPS detected the Pt 4f peak at each analyzed exfoliation site, the Bi 4f peak was measured at the exfoliation sites of PtBi2 and Pt(BiTe)2, and the Te 3d signal was identified at the exfoliation sites of Pt(BiTe)2 and PtTe2. The experimental peak positions and spin-orbit splittings are consistent with values reported in literature, with the exception of the Pt 4f peak of samples containing bismuth and the Te 3d peak of Pt(BiTe)2. Building on the experience and insight gathered during the KISS exfoliation process, an UHV KISS exfoliation chamber was designed using FreeCAD to visualize and discuss design changes aimed to improve exfoliation efficacy, efficiency, visibility, and reproducibility. Collectively, the findings of this research establish UHV KISS exfoliation as a promising approach for the production of large-area mono- and multilayer PtBi2, Pt(BiTe)2, and PtTe2 crystals on Ag(111)/mica substrates.
| Item Type: | Thesis (Master's Thesis / Essay) |
|---|---|
| Supervisor name: | Grubisic-Cabo, A. |
| Degree programme: | Applied Physics |
| Thesis type: | Master's Thesis / Essay |
| Language: | English |
| Date Deposited: | 30 Apr 2026 08:38 |
| Last Modified: | 30 Apr 2026 08:38 |
| URI: | https://fse.studenttheses.ub.rug.nl/id/eprint/37297 |
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