Reaction of the gas-phase hydrogen atom and the hydrogen-chemisorbed silicon surface : on sparsely hydrogen-chemisorbed surface

초록

The reaction of gas-phase atomic hydrogen with hydrogen atoms chemisorbed on the silicon surface is studied by use of the classical trajectory approach. In the model the gas atom interacts with the preadsorbed hydrogen atom and adjacent bare surface sites. The study shows that the chemisorption of H(g) is of major importance. Nearly all of the chemisorption events accompany the desorption of H(ad), i.e.. a displacement reaction. Although it is much less important than exchange reaction, the formation of H₂(g) is second most significant reaction pathway. At gas temperature 1800K and surface temperature 300K the probabilities of these two reactions are 0.739 and 0.064, respectively. The majority of the H₂ produced in the gas phase belongs to a fast component of the time-of-flight distribution for a direct mode reaction.