CHARGE-EXCHANGE AND EXCITATION IN NE+ A-SI COLLISION AT MEDIUM-ENERGY(2-30 KEV) - EXPERIMENT AND SIMULATION/

Ne+ ions were scattered from an amorphous silicon surface (a:Si) at re latively low incident energy (2-30 keV) to investigate the charge exch ange processes and the electronic excitation mechanisms. The study was carried out as a function of several experimental parameters: primary energy (E-0), incidence angle (alpha) and scattering angle (theta). W e show in this study that neutralization in the subsurface region of S i plays a significant role. The electron spectra show the same predomi nant Ne* autoionizing peaks as observed in scattering from metallic s urfaces and the core rearrangement mechanisms used for explaining the D-1 --> P-3 conversion are still valid. The conversion efficiency is a n increasing function of the incidence angle and a decreasing one of t he beam energy in the 1-5 keV range; however this efficiency remains n early constant at higher energies. This behaviour is attributed to a d irect production of Ne* states not assisted by core rearrangement pro cesses.