Title :
Thermoelectric Properties of Epitaxial Films of Layered Cobalt Oxides Fabricated by Topotactic Ion-Exchange Methods
Author :
Sugiura, Kenji ; Ohta, Hiromichi ; Nomura, Kenji ; Saito, Tomohiro ; Ikuhara, Yuichi ; Hirano, Masahiro ; Hosono, Hideo ; Koumoto, Kunihito
Author_Institution :
Graduate Sch. of Eng., Nagoya Univ.
Abstract :
Epitaxial film of a layered cobalt oxide, Ca3Co4 O9, was fabricated on a (0001)-face of alpha-Al2 O3 substrate by a topotactic ion exchange method using a Na0.8CoO2 epitaxial film as a precursor. High-resolution X-ray diffraction and atomic force microscope measurements revealed that the film was high-quality (001)-oriented Ca 3Co4O9 with stepped & terraced surface morphology. The film exhibits a high electrical conductivity of 2.95 times 102 Scm-1 and a large Seebeck coefficient of ~+125 muVK-1, which leads to the thermoelectric power factor of 4.5 times 10-4 Wm-1 K-1 at 300 K
Keywords :
Seebeck effect; X-ray diffraction; atomic force microscopy; calcium compounds; electrical conductivity; ion exchange; semiconductor epitaxial layers; semiconductor materials; surface chemistry; surface morphology; thermoelectric power; 2.95E2 S/cm; 300 K; AFM; Al2O3; Ca3Co4O9; Na0.8CoO2 epitaxial film precursor; Seebeck coefficient; X-ray diffraction; alpha-alumina substrate; atomic force microscopy; cobalt oxide thermoelectric properties; electrical conductivity; film orientation; film surface morphology; high resolution XRD; layered cobalt oxide epitaxial films; thermoelectric power factor; topotactic ion exchange methods; Atomic force microscopy; Atomic layer deposition; Atomic measurements; Cobalt; Conductive films; Force measurement; Substrates; Surface morphology; Thermoelectricity; X-ray diffraction;
Conference_Titel :
Thermoelectrics, 2006. ICT '06. 25th International Conference on
Conference_Location :
Vienna
Print_ISBN :
1-4244-0811-3
Electronic_ISBN :
1094-2734
DOI :
10.1109/ICT.2006.331290
