  Physical vapor deposition of Si onto transferred graphene is investigated. At
elevated temperatures, Si nucleates preferably on wrinkles and multilayer
graphene islands. In some cases, however, Si can be quasi-selectively grown
only on the monolayer graphene regions while the multilayer islands remain
uncovered. Experimental insights and ab initio calculations show that
variations in the removal efficiency of carbon residuals after the transfer
process can be responsible for this behavior. Low-temperature Si seed layer
results in improved wetting and enables homogeneous growth. This is an
important step towards realization of electronic devices in which graphene is
embedded between two Si layers.
