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

This report aims to describe the process and results on the decoupling between molecules and a silver substrate using insulating layers. Two insulating films were used, which were MgO and NaCl thin films grown on Ag(100) and Ag(111) crystals respectively. The samples were both grown epitaxially using a Knudsen Cell in an Ultra High Vacuum and investigated by a Low Temperature Scanning Tunneling 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 ensure that molecules would stick onto the thin films, and not diffuse off, the sample needed to be cooled down to a minimum of −25◦C. The bandgap for both insulating materials were charectarised, as well as IPS for all crystals, insulators and molecules used in this project. We concluded than both MgO and NaCl does decouple 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 discussed in accordance with the splitting and broadening.

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

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