Abstract
Herein we report the anisotropic carrier transport properties of a layered cobaltate, Nax CoO2 epitaxial film grown on the m -plane of an α -Al2 O3 substrate using reactive solid-phase epitaxy. Scanning and transmission electron microscopy analyses revealed that Nax CoO2 was heteroepitaxially grown with the CoO2 conducting planes inclined by ∼43° against the α -Al2 O3 substrate surface. The electrical resistivity parallel to the CoO2 planes was ∼1/5 of the perpendicular one, but the parallel Seebeck coefficient was about twice as large as the perpendicular one. Hence, a higher thermoelectric efficiency in the cobaltates can be obtained within the CoO2 planes.
Original language | English |
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Article number | 152105 |
Journal | Applied Physics Letters |
Volume | 94 |
Issue number | 15 |
DOIs | |
Publication status | Published - 2009 |
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)