Scanning tunneling microscopy of Si(001)

TLDR

Scanning tunneling microscopy was used to examine the atomic structure of the Si(001) surface. STM images show a dimer‑type reconstruction of Si(001) with both buckled and non‑buckled dimers forming (2×1), c(4×2), and p(2×2) domains, a high density of vacancy‑type defects that stabilize buckling at room temperature, and step‑defect structures that become increasingly faceted at high annealing temperatures.

Abstract

The atomic structure of the Si(001) surface has been examined with use of scanning tunneling microscopy (STM). The STM images reveal a dimer-type reconstruction and are inconsistent with chain and vacancy models. Both buckled and nonbuckled dimers are observed, giving rise to regions of (2\ifmmode\times\else\texttimes\fi{}1), c(4\ifmmode\times\else\texttimes\fi{}2), and p(2\ifmmode\times\else\texttimes\fi{}2) symmetry. The surface has a high density of vacancy-type defects, which appear to induce or stabilize buckling of the dimers at room temperature. The STM images also reveal the atomic structure at steps and defects. At high annealing temperature the step density increases dramatically, eventually leading to faceting.