Enhancement of the ultraviolet absorption and Raman efficiencies of a few nanometer thick Si-on-insulator

We show that a 3-7 nm thick Si-on-insulator (SOI) film displays UV absorption and Raman enhancement compared to bulk Si at a proper thickness of the buried oxide layer between the film and Si substrate. Experiment shows similar to fivefold SOI Raman enhancement for 3-4 nm thick films while theory predicts enhancement up to a factor of similar to 20 for 2 nm thick SOI. This discrepancy is attributed to non-uniformity of SOI thickness. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4757598]