Laser induced oxidation and optical properties of stoichiometric and non-stoichiometric Bi2Te3 nanoplates
- 300 Downloads
Bi-Te nanoplates (NPs) grown by a low pressure vapor transport method have been studied by Raman spectroscopy, atomic force microscopy (AFM), energy-dispersive X-ray spectroscopy (EDS), and Auger electron spectroscopy (AES). We find that the surface of relatively thick (more than tens of nanometers) Bi2Te3 NPs is oxidized in the air and forms a bump under heating with moderate laser power, as revealed by the emergence of Raman lines characteristic of Bi2O3 and TeO2 and characterization by AFM and EDS. Further increase of laser power burns holes on the surface of the NPs. Thin (thicknesses less than 20 nm) NPs with stoichiometry different from Bi2Te3 were also studied. Raman lines from non-stoichiometric NPs are different from those of stoichiometric ones and display characteristic changes with the increase of Bi concentration. Thin NPs with the same thickness but different stoichiometries show different color contrast compared to the substrate in the optical image. This indicates that the optical absorption coefficient in thin Bi-Te NPs strongly depends on their stoichiometry.
Keywordsbismuth telluride nanoplate Raman spectroscopy oxidation stoichiometry
Unable to display preview. Download preview PDF.
- Jones, P.; Huber, T. E.; Melngailis, J.; Barry, J.; Ervin, M. H.; Zheleva, T. S.; Nikolaeva, A.; Konopko, L.; Graf, M. Electrical contact resistance of bismuth telluride nanowires. In Proceedings of the 25th International Conference on Thermolelectrics, Vienna, Austria, 2006, pp 693–696.Google Scholar
- Salazar-Pérez, A. J.; Camacho-López, M. A.; Morales-Luckie, R. A.; Sánchez-Mendieta, V.; Ureña-Núñez, F.; Arenas-Alatorre, J. Structural evolution of Bi2O3 prepared by thermal oxidation of bismuth nano-particles. Superficies y Vacío 2005, 18, 4–8.Google Scholar