Regensburg 2022 – scientific programme

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O: Fachverband Oberflächenphysik

O 18: Poster Monday: 2D Materials 1

O 18.26: Poster

Monday, September 5, 2022, 18:00–20:00, P4

Changing structural and electronic properties of h-BN on Ir(111) by potassium intercalation — •Philip Grimm, Friedrich Wanierke, Felix Otto, Maximilian Schaal, Roman Forker, and Torsten Fritz — Institute of Solid State Physics, Friedrich Schiller University Jena, Helmholtzweg 5, 07743 Jena, Germany

2D hexagonal boron nitride (h-BN) is applied in electronics components, e.g., in gate dielectrics for transistors. However, its insulating behaviour is strongly influenced by the growth on metal substrates. One possibility to restore the insulating effect and to decouple h-BN is the intercalation of akali metals due to their low ionization energies.

In this study, we use h-BN grown by CVD on Ir(111) while potassium is deposited by thermal evaporation. The samples are investigated at various temperatures, the lateral structure by means of LEED as well as the electronic properties by means of XPS and (AR)PES. A (√3×√3)R30^∘ superstructure of K and a decrease of the moiré pattern originating from h-BN/Ir(111) is observed. In addition, the core levels and the band structure shifts to higher binding energies whereas the work function decreases by the similar value. Another observation is a disappearing band folding of the σ-bands. Due to the metastability of the superstructure at room temperature, we switched to low temperature at 35 K and observed even larger shifts of the core levels as well as of the band-structure (≈ 3 eV). In conclusion, our results indicate an intercalation of K in the 2D-system and consequently h-BN is decoupled from Ir(111).