TY - JOUR
T1 - Effect of self-grown seed layer on thermoelectric properties of ZnO thin films
AU - Saini, S.
AU - Mele, P.
AU - Honda, H.
AU - Suzuki, T.
AU - Matsumoto, K.
AU - Miyazaki, K.
AU - Ichinose, A.
AU - Molina Luna, L.
AU - Carlini, R.
AU - Tiwari, A.
N1 - Funding Information:
P. M. and S. S. thank “Institute for Sustainable Sciences and Development (ISSD), Hiroshima University , Higashi Hiroshima, Japan” for partial financial support under the framework of Japan Science and Technology Agency “program to Disseminate Tenure Tracking System”. P.M. acknowledges partial financial support of Kakenhi (C) grant No. 263901103 . Research at the University of Utah was supported by the U. S. National Science Foundation , Grant # 1121252 (NSF-MRSEC). P.M. and S.S. thank Prof T. Takabatake and Prof K. Suekuni from Department of Quantum Matter, ADSM, Hiroshima University, Japan for the fruitful discussion and experimental support. We appreciate Prof. P. E. Hopkins, Department of Mechanical and Aerospace Engineering, University of Virginia, USA, for the contribution of thermal conductivity experiment and fruitful discussion.
Publisher Copyright:
© 2015 Elsevier B.V. All rights reserved.
Copyright:
Copyright 2016 Elsevier B.V., All rights reserved.
PY - 2016/4/30
Y1 - 2016/4/30
N2 - The influence of self-grown seed has been studied on thermoelectric performance of 2% Al-doped ZnO(AZO) thin films. The thickness and orientation of c-axis domains in seed layer change on different substrates while other deposition conditions were kept unchanged for a comparable study. The changes occur because of the different nucleation process of thin film growth on substrate interface and the different lattice mismatch between AZO and substrate. Thin films are grown by pulsed laser deposition on single crystals (SrTiO3 (STO) and Al2O3) and cheap amorphous fused silica (FS) substrates at 400 °C. All thin films are c axis oriented. The grains are highly connected and elongated in shapewhich leads to high thermoelectric properties. The thicker self-grown seed layer is found in thin film deposited on FS substrates which shows best performance: electrical conductivity s=93 S/cm and Seebeck coefficient S=-203 μV/K, which estimate power factor (S2.σ) about 0.37 × 10-3Wm-1K-2 at 600 K.The value of thermal conductivity (k) was found lowest (4.89Wm-1K-1) for thin film deposited on FS than the other thin films (6.9Wm-1K-1 on Al2O3 and 6.55Wm-1K-1 on STO) at 300 K. The figure ofmerit, ZT=S2.σ.T/κ, is calculated 0.046 at 600 K, 5 times larger than the ZT of our previous reported bulk AZO,which is promising for practical applications of thermoelectric oxide thin films.
AB - The influence of self-grown seed has been studied on thermoelectric performance of 2% Al-doped ZnO(AZO) thin films. The thickness and orientation of c-axis domains in seed layer change on different substrates while other deposition conditions were kept unchanged for a comparable study. The changes occur because of the different nucleation process of thin film growth on substrate interface and the different lattice mismatch between AZO and substrate. Thin films are grown by pulsed laser deposition on single crystals (SrTiO3 (STO) and Al2O3) and cheap amorphous fused silica (FS) substrates at 400 °C. All thin films are c axis oriented. The grains are highly connected and elongated in shapewhich leads to high thermoelectric properties. The thicker self-grown seed layer is found in thin film deposited on FS substrates which shows best performance: electrical conductivity s=93 S/cm and Seebeck coefficient S=-203 μV/K, which estimate power factor (S2.σ) about 0.37 × 10-3Wm-1K-2 at 600 K.The value of thermal conductivity (k) was found lowest (4.89Wm-1K-1) for thin film deposited on FS than the other thin films (6.9Wm-1K-1 on Al2O3 and 6.55Wm-1K-1 on STO) at 300 K. The figure ofmerit, ZT=S2.σ.T/κ, is calculated 0.046 at 600 K, 5 times larger than the ZT of our previous reported bulk AZO,which is promising for practical applications of thermoelectric oxide thin films.
KW - Al-doped ZnO thin films
KW - Figure of merit
KW - High temperature applications
KW - Pulsed laser deposition
KW - Seebeck coefficient
KW - Self-grown seed layer
KW - Thermoelectric oxides
KW - c-axis orientation
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U2 - 10.1016/j.tsf.2015.09.060
DO - 10.1016/j.tsf.2015.09.060
M3 - Article
AN - SCOPUS:84951753011
VL - 605
SP - 289
EP - 294
JO - Thin Solid Films
JF - Thin Solid Films
SN - 0040-6090
ER -