Characterization of MgO and NaCl as Decoupling Layers and Investigation of the Structural and Electronic Properties of C60

Ebenau, Lucas Kjær ; Ahmed, Metin

4. term (FYS10)

Physics, Master

2024

2024-05-31

46 pages

This report aims to describe the process and results on the decoupling between molecules and a silver substrate using in- sulating layers. Two insulating films were used, which were MgO and NaCl thin films grown on Ag(100) and Ag(111) crys- tals respectively. The samples were both grown epitaxially using a Knudsen Cell in an Ultra High Vacuum and investigated by a Low Temperature Scanning Tunnel- ing Microscope. Both thin film materials has been worked with before in the STM setup used in this project, but for C60 molecule adsorbtion the recipes needed to be tweaked to gain larger coverage. To en- sure that molecules would stick onto the thin films, and not diffuse off, the sam- ple needed to be cooled down to a mini- mum of −25◦C. The bandgap for both in- sulating materials were charectarised, as well as IPS for all crystals, insulators and molecules used in this project. We con- cluded than both MgO and NaCl does de- couple the molecules from the substrate. Lastly the HOMO, LUMO and LUMO+1 of C60 were measured, where the splitting and broadening of LUMO+1 values were discussed and the HOMO-LUMO was dis- cussed in accordance with the splitting and broadening.

Isolerende ; NaCl ; MgO ; C60 ; STS ; STM ; HOMO ; LUMO ; IPS ; Båndgab ; Overfladefysik ; Overfladetisltande ; Epitaxy

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