Size-dependent detachment-limited decay kinetics of two-dimensional TiN islands on TiN(111)

In situ high-temperature (T-a=1050-1250 K) scanning tunneling microscopy was used to determine the coarsening and decay kinetics of two-dimensional TiN adatom and vacancy islands on atomically smooth TiN(111) terraces. We report the first observation of an abrupt decrease in decay rates, irrespective of T-a, of adatom islands with areas less than a critical value of 1600 Angstrom(2). However, no decay rate transition was observed for vacancy islands. We attribute the size-dependent island decay behavior, which is consistent with detachment-limited kinetics, to anisotropic attachment and detachment barriers.