Chemical interaction of H and D atoms with Ag∕H:p-Si(111) thin film diodes

Abstract

During exothermic reactions of atomic hydrogen or deuterium on a silver surface hot charge carriers are produced which have been observed by using Ag∕p-Si(111) Schottky diodes. Thin film devices provide a means to bring a charge detector as close to the reaction site as the mean free path of the charge carriers. In the case of a p-doped substrate the Schottky barrier works as a high-pass energy filter for hot holes. The authors have therefore produced large area Schottky diodes with film thicknesses of up to 30nm varying the thickness to rule out any influence of this device parameter. Those diodes were then exposed to beams of hydrogen atoms and deuterium atoms produced in a hot capillary source. Gas exposures do not affect the Schottky barrier height significantly. While exposing the samples to defined atom fluxes, the closed-loop current was monitored in real time. It shows that the current is proportional to the flux of atoms impinging on the surface. The authors have found hydrogen to generate 3.7 ti...