Berlin 2015 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 99: Semiconductor Substrates: Structure, Epitaxy and Growth

O 99.5: Vortrag

Freitag, 20. März 2015, 11:30–11:45, MA 042

Nanoscale Structure of Si/SiO₂/Organics Interfaces — •Hans-Georg Steinrück¹, Andreas Schiener¹, Torben Schindler¹, Johannes Will¹, Andreas Magerl¹, Oleg Konovalov², Giovanni Li Destri², Oliver H. Seeck³, Markus Mezger⁴, Julia Haddad⁵, Moshe Deutsch⁵, Antonio Checco⁶, and Benjamin M. Ocko⁶ — ¹FAU, Germany — ²ESRF, France — ³DESY, Germany — ⁴MPI Mainz, Germany — ⁵Bar-Ilan University, Israel — ⁶BNL, USA

Single-crystal silicon is by far the most widely used substrate for the deposition of organic thin films. It’s surface is invariably terminated by a few nanometer-thick amorphous native SiO₂ layer. The structure of the transition layer between the silicon and it’s oxide is neither well characterized nor well understood at present.

Using high-resolution x-ray reflectivity measurements of increasingly more complex interfaces involving silicon (001) substrates, we reveal the existence of a low-density, few-angstrom-thick, transition layer at the Si/SiO₂ interface [1]. The importance of accounting for this layer in modeling silicon/liquid interfaces and silicon-supported monolayers is demonstrated by comparing fits of reflectivity curves by models including this layer and the widely used Tidswell model [2], which excludes this layer. The 6-8 missing electrons per silicon unit cell area found here support previous theoretical models and simulations of the Si/SiO₂ interface [3].

[1] H.-G. Steinrück et al., ACS Nano (2014), DOI: 10.1021/nn5056223.

[2] I. M. Tidswell et al., Phys. Rev. B 41, 1111 (1990).

[3] Y. Tu and J. Tersoff, Phys. Rev. Lett. 84, 4393 (2000).