Effect of self-grown seed layer on thermoelectric properties of ZnO thin films

S. Saini, P. Mele, H. Honda, T. Suzuki, K. Matsumoto, K. Miyazaki, A. Ichinose, L. Molina Luna, R. Carlini, A. Tiwari

Research output: Contribution to journalArticle

21 Citations (Scopus)

Abstract

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.

Original languageEnglish
Pages (from-to)289-294
Number of pages6
JournalThin Solid Films
Volume605
DOIs
Publication statusPublished - 2016 Apr 30

Keywords

  • Al-doped ZnO thin films
  • Figure of merit
  • High temperature applications
  • Pulsed laser deposition
  • Seebeck coefficient
  • Self-grown seed layer
  • Thermoelectric oxides
  • c-axis orientation

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films
  • Metals and Alloys
  • Materials Chemistry

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