Premium
Stoichiometry Controlled, Single‐Crystalline Bi 2 Te 3 Nanowires for Transport in the Basal Plane
Author(s) -
Peranio Nicola,
Leister Eva,
Töllner William,
Eibl Oliver,
Nielsch Kornelius
Publication year - 2012
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.201101273
Subject(s) - materials science , nanowire , thermoelectric effect , grain boundary , seebeck coefficient , thermoelectric materials , electron diffraction , transmission electron microscopy , stoichiometry , diffraction , condensed matter physics , nanotechnology , composite material , optics , thermal conductivity , microstructure , chemistry , physics , organic chemistry , thermodynamics
Thermoelectric Bi 2 Te 3 based bulk materials are widely used for solid‐state refrigeration and power‐generation at room temperature. For low‐dimensional and nanostructured thermoelectric materials an increase of the thermoelectric figure of merit ZT is predicted due to quantum confinement and phonon scattering at interfaces. Therefore, the fabrication of Bi 2 Te 3 nanowires, thin films, and nanostructured bulk materials has become an important and active field of research. Stoichiometric Bi 2 Te 3 nanowires with diameters of 50–80 nm and a length of 56 μm are grown by a potential‐pulsed electrochemical deposition in a nanostructured Al 2 O 3 matrix. By transmission electron microscopy (TEM), dark‐field images together with electron diffraction reveal single‐crystalline wires, no grain boundaries can be detected. The stoichiometry control of the wires by high‐accuracy, quantitative enegy‐dispersive X‐ray spectroscopy (EDX) in the TEM instrument is of paramount importance for successfully implementing the growth technology. Combined electron diffraction and EDX spectroscopy in the TEM unambiguously prove the correct crystal structure and stoichiometry of the Bi 2 Te 3 nanowires. X‐ray and electron diffraction reveal growth along the [110] and [210] directions and the c axis of the Bi 2 Te 3 structure lies perpendicular to the wire axis. For the first time single crystalline, stoichiometric Bi 2 Te 3 nanowires are grown that allow transport in the basal plane without being affected by grain boundaries.