Raman Scattering from Ge Nanocrystals on Si Substrates: Problems and Solutions.

摘要

This document demonstrates that in many cases the experimentally observed peak at about 300/cm is in fact originating from the Si substrate. We have found that the most promising ways to tackle this problem are (I) use of resonant Raman and/or (2) use of polarized Raman scattering. The former is more efficient to excite the Ge nanoclusters but also results in stronger photoluminescence which can make the measurement more difficult. Our results also demonstrate that Raman scattering can be used as an efficient probe only if Ge concentration exceeds a certain value.