Scanning Tunneling Microscopy of Si Donors in GaAs

Abstract

Using scanning tunneling microscopy, we have identified and characterized Si donors (Si{sub Ga}) in GaAs located on the (110) surface and in subsurface layers. Si{sub Ga} on the surface shows localized features with characteristic structures in good agreement with a recent theoretical calculation. Si{sub Ga} in subsurface layers appears as delocalized protrusions superimposed on the background lattice, which are interpreted in terms of the modification of the tunneling due to the tip-induced band bending perturbed by the Si{sub Ga} Coulomb potential.