0000000000237259
AUTHOR
Marisol Martín-gonzález
Nanowires: A route to efficient thermoelectric devices
Miniaturization of electronic devices aims at manufacturing ever smaller products, from mesoscopic to nanoscopic sizes. This trend is challenging because the increased levels of dissipated power demands a better understanding of heat transport in small volumes. A significant amount of the consumed energy in electronics is transformed into heat and dissipated to the environment. Thermoelectric materials offer the possibility to harness dissipated energy and make devices less energy-demanding. Heat-to-electricity conversion requires materials with a strongly suppressed thermal conductivity but still high electronic conduction. Nanowires can meet nicely these two requirements because enhanced …
The fingerprint of Te-rich and stoichiometric Bi2Te3 nanowires by Raman spectroscopy
We unambiguously show that the signature of Te-rich bismuth telluride is the appearance of three new peaks in the Raman spectra of Bi2Te3, located at 88, 117 and 137 cm−1 . For this purpose, we have grown stoichiometric Bi2Te3 nanowires as well as Te-rich nanowires. The absence of these peaks in stoichiometric nanowires, even in those with the smallest diameter, shows that they are not related to confinement effects or the lack of inversion symmetry, as stated in the literature, but to the existence of Te clusters. These Te clusters have been found in nonstoichiometric samples by high resolution electron microscopy, while they are absent in stoichiometric samples. The Raman spectra of the l…
Enhanced thermoelectric properties of lightly Nb doped SrTiO3 thin films
Novel thermoelectric materials developed for operation at room temperature must have similar or better performance along with being as ecofriendly as those commercially used, e.g., BiTe, in terms of their toxicity and cost. In this work, we present an in-depth study of the thermoelectric properties of epitaxial Nb-doped strontium titanate (SrTiNbO) thin films as a function of (i) doping concentration, (ii) film thickness and (iii) substrate type. The excellent crystal quality was confirmed by high resolution transmission electron microscopy and X-ray diffraction analysis. The thermoelectric properties were measured by the three-omega method (thermal conductivity) and van der Pauw method (el…