University of Northern Iowa, Physics, Cedar Falls, IA 50613
In this project we use optical spectroscopic techniques to explore the interface properties of nanoplates of a representative topological insulator material Bi2Te3. By using Raman spectroscopy we probe the phonon properties of nanoplates as-grown on SiO2 substrate. The emergence of infrared-acitve modes in Raman scattering reveals a breakdown of inversion symmetry in as-grown nanoplates. In nanoplates that are transferred to another SiO2 substrate, the infrared-active modes are absent and the Raman spectra are similar to those from bulk Bi2Te3. The difference in the Raman spectra between the as-grown and transferred nanoplates could be attributed to the difference in substrate-nanoplate interactions.
[Abstract (DOCX)]