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Low loss EELS and EFTEM study of Bi 2Te 3 based bulk and nanomaterials

: Peranio, N.; Aabdin, Z.; Töllner, W.; Winkler, M.; König, J.; Eibl, O.; Nielsch, K.; Böttner, H.


Nanoscale heat transfer - thermoelectrics, thermophotovoltaics and emerging thermal devices : April 25 - 29, 2011, San Francisco
Red Hook, NY: Curran, 2011 (Materials Research Society Symposium Proceedings 1329)
ISBN: 978-1-618-39526-9
ISSN: 0272-9172
MRS Spring Meeting <2011, San Francisco>
Symposium I, Nanoscale Heat Transfer -Thermoelectrics, Thermophotovoltaics and Emerging Thermal Devices <2011, San Francisco>
Conference Paper
Fraunhofer IPM ()

Energy-filtered transmission electron microscopy (EFTEM) yields new possibilities for the investigation of Bi 2Te 3 based nanomaterials. Combined low-loss electron energy-loss spectroscopy (EELS) and energy-dispersive x-ray microanalysis (EDS) and energy-filtered TEM were applied on a Zeiss 912 TEM to investigate nanowires, thin films, and bulk materials. Multilayered Bi-Sb-Te nanowires with a diameter of 65 nm and a period of 200 nm and stoichiometric Bi 2Te 3 nanowires were grown by potential-pulsed electrochemical deposition. Tellurium elemental maps of the multilayered nanowires were obtained by two-window edge-jump ratio images (EJI). EDS chemical analysis showed that small Te fluctuations of 3 at.% yielded significant contrast in EJI. Energy-filtered TEM applied on nano-alloyed Bi 2Te 3 thin films grown by molecular beam epitaxy (MBE) revealed 10-20 nm thick Bi-rich blocking layers at grain boundaries. Plasmon spectroscopy by EELS was applied on Bi 2(Te 0.91Se 0.09) 3 bulk and yielded a plasmon energy of 16.9 eV. Finally, plasmon dispersion was measured for Bi 2(Te 0.91Se 0.09) 3bulk by angle-resolved EELS, which yields a fingerprint of the anisotropy and the dimensionality of the electronic structure of the materials.