While the Ge(0 0 1) surface has been extensively studied, it is still debated whether it is of conducting or semiconducting nature at room temperature. The evidence collected by angle-resolved photoelectron spectroscopy experiments in the past has led to the preliminary attribution of a semiconducting nature at room temperature. In contrast, we show in this work that the pristine Ge(0 0 1) surface is conducting at room temperature by using temperature-dependent angle-resolved photoelectron spectroscopy, scanning tunneling microscopy and first principles calculations. Specifically, a surface band located ∼200 meV above the valence band maximum has been observed at room temperature. This surface band shows anisotropic dispersions along the [0 1 0] and [1 1 0] directions, but it disappears at lower measurement temperature, which indicates its occupation by thermally excited electrons. State-of-the-art density functional theory calculations undoubtedly attribute this surface band to the unoccupied π*-band formed by dangling bonds on the c(4 × 2) surface reconstruction, while evidencing fundamental differences with the p(2 × 1) reconstruction. Furthermore, the calculations demonstrate that the valence band structure observed in angle-resolved photoelectron spectroscopy experiments arise from projected bulk states and is thus insensitive to surface contamination. Our results contribute to the fundamental knowledge of the Ge(0 0 1) surface and to a better understanding of its role in micro- and opto-electronic devices.

Reichmann, F., Scalise, E., Becker, A., Hofmann, E., Dabrowski, J., Montalenti, F., et al. (2022). New insights into the electronic states of the Ge(0 0 1) surface by joint angle-resolved photoelectron spectroscopy and first-principle calculation investigation. APPLIED SURFACE SCIENCE, 571(1 January 2022) [10.1016/j.apsusc.2021.151264].

New insights into the electronic states of the Ge(0 0 1) surface by joint angle-resolved photoelectron spectroscopy and first-principle calculation investigation

Scalise E.
;
Montalenti F.;Miglio L.;
2022

Abstract

While the Ge(0 0 1) surface has been extensively studied, it is still debated whether it is of conducting or semiconducting nature at room temperature. The evidence collected by angle-resolved photoelectron spectroscopy experiments in the past has led to the preliminary attribution of a semiconducting nature at room temperature. In contrast, we show in this work that the pristine Ge(0 0 1) surface is conducting at room temperature by using temperature-dependent angle-resolved photoelectron spectroscopy, scanning tunneling microscopy and first principles calculations. Specifically, a surface band located ∼200 meV above the valence band maximum has been observed at room temperature. This surface band shows anisotropic dispersions along the [0 1 0] and [1 1 0] directions, but it disappears at lower measurement temperature, which indicates its occupation by thermally excited electrons. State-of-the-art density functional theory calculations undoubtedly attribute this surface band to the unoccupied π*-band formed by dangling bonds on the c(4 × 2) surface reconstruction, while evidencing fundamental differences with the p(2 × 1) reconstruction. Furthermore, the calculations demonstrate that the valence band structure observed in angle-resolved photoelectron spectroscopy experiments arise from projected bulk states and is thus insensitive to surface contamination. Our results contribute to the fundamental knowledge of the Ge(0 0 1) surface and to a better understanding of its role in micro- and opto-electronic devices.
Si
Articolo in rivista - Articolo scientifico
Scientifica
ARPES; DFT; Ge(0 0 1); Germanium; Surface;
English
Reichmann, F., Scalise, E., Becker, A., Hofmann, E., Dabrowski, J., Montalenti, F., et al. (2022). New insights into the electronic states of the Ge(0 0 1) surface by joint angle-resolved photoelectron spectroscopy and first-principle calculation investigation. APPLIED SURFACE SCIENCE, 571(1 January 2022) [10.1016/j.apsusc.2021.151264].
Reichmann, F; Scalise, E; Becker, A; Hofmann, E; Dabrowski, J; Montalenti, F; Miglio, L; Mulazzi, M; Klesse, W; Capellini, G
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/10281/330699
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