The nucleation of Pt films grown by ion beam assisted deposition on Pt
(lll) has been studied by scanning tunneling microscopy. At temperatur
es T greater than or equal to 200 K, the simultaneous ion bombardment
during vapor phase deposition leads to a substantial increase in the i
sland number density caused by nucleation at ion impact induced adatom
clusters. This increase is observed even in the higher temperature ra
nge where after ion bombardment alone the ion impact induced adatom cl
usters are no longer present. (C) 1995 American Institute of Physics.