Point defect configurations of supersaturated Au atoms inside Si nanowires

Nano Lett. 2008 Apr;8(4):1016-9. doi: 10.1021/nl072670+. Epub 2008 Mar 13.

Abstract

Aberration-corrected scanning transmission electron microscopy (STEM) is used to reveal individual Au atom configurations inside Si nanowires grown by Au-catalyzed vapor-liquid-solid (VLS) molecular beam epitaxy (MBE). We identify a substitutional and three distinct interstitial configurations, one of which has not been previously identified. We confirm the stability of the observed point defect configurations by density functional theory (DFT) calculations. The observed number densities of the various configurations are in accord with their calculated formation energies. The concentration of Au atoms is larger than the solubility limit, but the effect may be caused by the STEM beam.