Porosity-tuned thermal conductivity in thermoelectric Al-doped ZnO thin films grown by mist-chemical vapor deposition

Shrikant Saini, Paolo Mele, Takafumi Oyake, Junichiro Shiomi, Janne Petteri Niemelä, Maarit Karppinen, Koji Miyazaki, Chaoyang Li, Toshiyuki Kawaharamura, Ataru Ichinose, Leopoldo Molina-Luna

Research output: Contribution to journalArticle

Abstract

The potential of thermoelectric thin films lies in wide range of applications from micro-energy harvesting to the sensors. For this, it is essential to have high power factor and ultra-low thermal conductivity which have been reported in thin films produced by expensive vacuum techniques. However, for practical applications, it is essential to use inexpensive technique to grow thin film in large area. In this direction, we report the use of mist-chemical vapor deposition (CVD) technique to develop oxide thin films for thermoelectric application. We grow c-axis oriented nano-porous thin films of 2% Al-doped ZnO (AZO). These nano-porous films have enhance phonon scattering which results in the depression of thermal conductivity (κ) while maintaining similar order of magnitude of power factor as reported in dense films prepared by vacuum techniques. For example, κ300K decreases from 6.5 W/m.K for dense thin film (porosity = 7.9%) grown by pulsed laser deposition to 5.54 W/m.K for porous film (porosity = 24.2%) grown by mist-CVD while maintaining the power factor of similar order of magnitude for AZO film deposited on SrTiO3. The depression of thermal conductivity in porous films may lead to higher figure of merit which is promising for practical applications of thermoelectric oxide films.

Original languageEnglish
Pages (from-to)180-185
Number of pages6
JournalThin Solid Films
Volume685
DOIs
Publication statusPublished - 2019 Sep 1

Fingerprint

mist
Fog
Chemical vapor deposition
Thermal conductivity
thermal conductivity
Porosity
vapor deposition
porosity
Thin films
thin films
Oxide films
Vacuum
vacuum
Phonon scattering
Energy harvesting
Pulsed laser deposition
figure of merit
pulsed laser deposition
oxide films
oxides

Keywords

  • Mist-chemical vapor deposition
  • Oxides
  • Porosity
  • Thermoelectric effect
  • Thin film
  • Zinc oxide

ASJC Scopus subject areas

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

Cite this

Porosity-tuned thermal conductivity in thermoelectric Al-doped ZnO thin films grown by mist-chemical vapor deposition. / Saini, Shrikant; Mele, Paolo; Oyake, Takafumi; Shiomi, Junichiro; Niemelä, Janne Petteri; Karppinen, Maarit; Miyazaki, Koji; Li, Chaoyang; Kawaharamura, Toshiyuki; Ichinose, Ataru; Molina-Luna, Leopoldo.

In: Thin Solid Films, Vol. 685, 01.09.2019, p. 180-185.

Research output: Contribution to journalArticle

Saini, S, Mele, P, Oyake, T, Shiomi, J, Niemelä, JP, Karppinen, M, Miyazaki, K, Li, C, Kawaharamura, T, Ichinose, A & Molina-Luna, L 2019, 'Porosity-tuned thermal conductivity in thermoelectric Al-doped ZnO thin films grown by mist-chemical vapor deposition', Thin Solid Films, vol. 685, pp. 180-185. https://doi.org/10.1016/j.tsf.2019.06.010
Saini, Shrikant ; Mele, Paolo ; Oyake, Takafumi ; Shiomi, Junichiro ; Niemelä, Janne Petteri ; Karppinen, Maarit ; Miyazaki, Koji ; Li, Chaoyang ; Kawaharamura, Toshiyuki ; Ichinose, Ataru ; Molina-Luna, Leopoldo. / Porosity-tuned thermal conductivity in thermoelectric Al-doped ZnO thin films grown by mist-chemical vapor deposition. In: Thin Solid Films. 2019 ; Vol. 685. pp. 180-185.
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