Notes:

Ellipsometry measurements and TEM imaging were performed at the Center for Nanoscale Systems (CNS), a member of the National Nanotechnology Infrastructure Network (NNIN), which is supported by the National Science Foundation (NSF) under award No. ECS-0335765. CNS is part of Harvard University. This work was supported by the Air Force Office of Scientific Research (AFOSR), award No. FA9550- 09-1-0669-DOD35CAP. IBB acknowledges support from the Natural Sciences and Engineering Research Council of Canada (NSERC) through the Postgraduate Scholarship - Doctoral (PGS-D) program.