Electronic energy loss and straggling in low energy H⁺ and H₂ ⁺ interaction with silicon films

The appearance of atomic structures of nanoscopic dimensions, with new and interesting physical properties, requires revisiting various aspects of particle interaction with solid matter. For this purpose in this work we present a study of electronic energy loss of H+ and protons (fragments) from the dissociation of H-2 (+) ions interacting with ultra-thin amorphous silicon films for incident beam energies from 1 to 10 keV/u. We report measurements of energy distributions of transmitted protons and molecular fragments through these films, from which we derive the average energy losses and the energy loss straggling. Our experimental findings turn out to be in good agreement with nonlinear electronic stopping power models and some previous experimental data.