Dynamical interaction of surface electron-hole pairs with surface defects: Surface spectroscopy monitored by particle emissions

Excitation spectra and optical anisotropy for laser-induced ${\mathrm{Ga}}^0$ emission initiated by defects on GaAs(110) surfaces have been measured. It is found that the ${\mathrm{Ga}}^0$ emission yield is enhanced sharply when the photon energy increases across both 1.87 and 2.55 eV and that the enhancement is much larger for photons polarized parallel to the [11¯0] direction than for those polarized perpendicular. The result indicates that electron-hole pairs on the surface are particularly effective in the defect-initiated emission of ${\mathrm{Ga}}^0$.