RAMAN-SCATTERING INVESTIGATION ON THE ORDERED INCORPORATION OF SI DOPANT ATOMS ON GAAS(001) VICINAL SURFACES DURING MBE GROWTH

Using Raman scattering by local vibrational modes (LVM) and collective electronic excitations we have investigated the ordered incorporation of Si dopant atoms on vicinal GAAs(001) surfaces. LVM spectra revealed for a sequence of delta-doped samples grown by molecular beam epitaxyy (MBE) under specific conditions that the Si dopant atoms are predominantly incorporated on Ga-sites even at a doping concentration as high as 1.8 x 10(13) cm(-2). For a sample grown under conditions established by real-time high-energy electron diffraction (RHEED) to be favourable for the wire-like Si incorporation, a pronounced polarization asymmetry in the Raman scattering intensity of collective intersubband plasmon-phonon modes arising from the delta-doping layer has been found.