No abstract

ions were scattered from an amorphous silicon surface (a:Si) at relatively low incident energy (2-30 keV) to investigate the charge exchange processes and the electronic excitation mechanisms. The study was carried out as a function of several experimental parameters: primary energy , incidence angle and scattering angle . We show in this study that neutralization in the subsurface region of Si plays a significant role. The electron spectra show the same predominant autoionizing peaks as observed in scattering from metallic surfaces and the core rearrangement mechanisms used for explaining the conversion are still valid. The conversion efficiency is an increasing function of the incidence angle and a decreasing one of the beam energy in the 1-5 keV range; however this efficiency remains nearly constant at higher energies. This behaviour is attributed to a direct production of states not assisted by core rearrangement processes.