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arXiv · 1902.02958

Fermi level pinning by defects can explain the large reported carbon 1s binding energy variations in diamond

Michael Walter·Filippo Mangolini·J. Brandon McClimon·Robert W. Carpick·Michael Moseler
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Abstract

The quantitative evaluation of the carbon hybridization state by X-ray photoelectron spectroscopy (XPS) has been a surface-analysis problem for the last three decades due to the challenges associated with the unambiguous identification of the characteristic binding energy values for sp$^2$ and sp$^3$-bonded carbon. While the sp$^2$ binding energy is well established, there is disagreement for the sp$^3$ value in the literature. Here, we compute the binding energy values for model structures of pure and doped-diamond using density functional theory. The simulation results indicate that the large band-gap of diamond allows defects to pin the Fermi level, which results in large variations of the C(1s) core electron energies for sp$^3$-bonded carbon, in agreement with the broad range of experimental C(1s) binding energy values for sp$^3$ carbon reported in the literature. Fermi level pinning by boron is demonstrated by experimental C(1s) binding energies of highly B-doped ultrananocrystalline diamond that are in good agreement to simulations.

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Michael Walter, Filippo Mangolini, J. Brandon McClimon, Robert W. Carpick, Michael Moseler. 2019-02-08. Fermi level pinning by defects can explain the large reported carbon 1s binding energy variations in diamond. https://arxiv.org/abs/1902.02958

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