We detected the H + ions recoiled from Si(1 1 1)-1 × 1-H by medium energy 80-150 keV Ne + impacts. The H + fraction is dependent on emerging angle and emerging energy. With decreasing the emerging angle scaled from the surface normal the H + fraction increases and reaches a saturation below ∼70° and almost 100% for emerging energy above 13 keV. In contrast, the charge state is not equilibrated even at ∼85°. Such strong dependence on emerging angle is due to the location of H bound by Si atoms on top of the surface. The sensitivity to H on the surfaces is estimated to be better than 5 × 10 12 atoms/cm 2 at a small emerging angle (θ out < ∼75°), where the H + fraction reaches ∼100%. The unexpectedly large energy spread for the recoiled H + spectra is attributed to the Doppler broadening caused by the zero-point energy of the vibrating H-Si system and additionally to small energy transfers among the three bodies of Ne + and H-Si, although the assumption of binary collision between Ne + and H is approximately valid. This H detection technique can be widely applied to analysis of chemical reactions including adsorption and desorption mediated by water and hydroxyl on various kinds of metal-oxide surfaces.
|Number of pages||6|
|Journal||Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms|
|Publication status||Published - Apr 1 2012|
All Science Journal Classification (ASJC) codes
- Nuclear and High Energy Physics