Chemisorption energy of hydrogen on silicon surfaces

By: M. B. Raschke and U. Höfer

Physical Review B 63, 01303/1-4 (2001)

The chemisorption energy of H2 on Si(111)7x7 and Si(001)2x1 was determined from thermodynamic equilibrium experiments in an ultrahigh vacuum quartz apparatus at temperatures of 760 to 970 K. The obtained values of 1.7 +/- 0.2 eV for Si(111) and 1.9 +/- 0.3 eV for Si(001) correspond to Si-H bond energies of 3.1 and 3.2 eV, respectively. Hydrogen bonding with silicon surfaces is thus found to be considerably weaker than in silane molecules and homologous clusters.