Redistribution of epitaxial Si on (001) GaAs during overgrowth by GaAs

Abstract
We examine the stability of pseudomorphic submonolayer Si films embedded in (001) GaAs by molecular-beam epitaxy. Secondary ion-mass spectrometry depth profiling reveals the presence of 1019 Si-atoms/cm3 in the first 40 nm of the GaAs cap layer. The systematic investigation of samples having different cap thickness by Hall effect measurements and local vibrational mode Raman spectroscopy allows us to identify the site distribution of Si atoms in the cap layer and yields insight into the migration mechanism.