Precursor states in the adsorption of Sb4 on Si(001)

Abstract

The surprising complexity of the reaction path of the dissociation of Sb4 and Si(001) is revealed by scanning tunneling microscopy (STM). Four distinct types of precursors are identified, which can be converted to the final state of two-dimer clusters through thermal annealing, or through a novel STM-tip-induced conversion. An effective energy barrier of 0.50.1 eV and an effective prefactor of 103 Hz are measured for the thermal conversion of precursors to the final state. The results indicate that popular models assuming only one precursor state may fail for many semiconductor systems. © 1992 The American Physical Society.