Berlin 2012 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 35: Poster Session II (Polymeric biomolecular films; Nanostructures; Electronic structure; Spin-orbit interaction; Phase transitions; Surface chemical reactions; Heterogeneous catalysis; Particles and clusters; Surface magnetism; Electron and spin dynamics; Surface dynamics; Methods; Electronic structure theory; Functional molecules)

O 35.37: Poster

Dienstag, 27. März 2012, 18:15–21:45, Poster B

Nitridation of diamond - a possible way to n-type surface-conductivity? — •Nora Jenny Vollmers, Uwe Gerstmann, and Wolf Gero Schmidt — Theoretische Physik, Universität Paderborn

Diamond has a lot of outstanding qualities but the lack of a suitable n-type donor has hindered this material to gain broad technological application. Nevertheless, nitrogen doping was already successfully used to improve the emission behavior of field emission devices based on a-C:H diamond thin films [1, 2, 3]. In this theoretical work we want to propose a possible way to n-type surface conductivity at the clean diamond (001) (2×1) reconstructed surface which consists of flat dimer rows. Using density functional theory together with the Quantum ESPRESSO PWscf package [4], we compare the electronic and magnetic properties for different N incorporation depths. Built-in directly at the surface, N gives rise to localized surface states similar to intrinsic carbon dangling bond-like states. Otherwise N is able to introduce surface conductivity as demonstrated by ab initio calculated effective mass tensors. In addition, the extreme anisotropy of the effective mass tensor comparable with those of metallic indium-chains on silicon substrates indicates the possibility to achieve n-type 1D surface-conductivity along the dimer-chains.

[1] R.S. Balmer et al., J. Phys.: Cond. Matt. 21, 364221 (2009).

[2] J. Xu et al., Appl. Phys. A 80, 123 (2005).

[3] M. Kaukkonen et al., Phys. Rev. Lett. 83, 5346 (1999).

[4] Ch.J. Pickard, F. Mauri, Phys. Rev. Lett. 88, 086403 (2002).