REFLECTANCE ANISOTROPY SPECTRA FROM SI DELTA-DOPED GAAS(001) - CORRELATION OF LINEAR ELECTROOPTIC EFFECT WITH INTEGRATED SURFACE FIELD

Reflectance anisotropy spectroscopy (RAS) has been employed in situ to investigate the overlayer growth of GaAs onto submonolayer to one mon olayer coverages of Si delta layers deposited on the GaAs(001)-c(4x4) surface. The intensity of RAS features, thought to arise from the Line ar electro-optic (LEG) effect, is found to vary with both the number o f atoms in the Si delta layer and the position of the delta plane from the GaAs surface. Self-consistent solutions to Poisson's equation are made to calculate the electric field in the near-surface region of th e samples. The results show a direct correlation between the LEO inten sity and the surface field averaged over the penetration depth of the incident radiation, in confirmation of the LEO model.