Thermal Conductivity of Nano-Crystallized Indium-Gallium-Zinc Oxide Thin Films Determined by Differential Three-Omega Method
The temperature dependence thermal conductivity of the indium-gallium-zinc oxide (IGZO) thin films was investigated with the differential three-omega method for the clear demonstration of nanocrystallinity. The thin films were deposited on an alumina (α-Al<sub>2</sub>O<sub>3</su...
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doaj-5fa5f9e2c57c49859c657d293c655a9a2021-06-30T23:57:15ZengMDPI AGNanomaterials2079-49912021-06-01111547154710.3390/nano11061547Thermal Conductivity of Nano-Crystallized Indium-Gallium-Zinc Oxide Thin Films Determined by Differential Three-Omega MethodRauf Khan0Michitaka Ohtaki1Satoshi Hata2Koji Miyazaki3Reiji Hattori4Department of Applied Science for Electronics and Materials, Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, Fukuoka 816-8580, JapanDepartment of Applied Science for Electronics and Materials, Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, Fukuoka 816-8580, JapanDepartment of Applied Science for Electronics and Materials, Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, Fukuoka 816-8580, JapanDepartment of Mechanical and Control Engineering, Kyushu Institute of Technology, Fukuoka 804-8550, JapanDepartment of Applied Science for Electronics and Materials, Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, Fukuoka 816-8580, JapanThe temperature dependence thermal conductivity of the indium-gallium-zinc oxide (IGZO) thin films was investigated with the differential three-omega method for the clear demonstration of nanocrystallinity. The thin films were deposited on an alumina (α-Al<sub>2</sub>O<sub>3</sub>) substrate by direct current (DC) magnetron sputtering at different oxygen partial pressures ([PO<sub>2</sub>] = 0%, 10%, and 65%). Their thermal conductivities at room temperature were measured to be 1.65, 1.76, and 2.58 Wm<sup>−1</sup>K<sup>−1</sup>, respectively. The thermal conductivities decreased with an increase in the ambient measurement temperature. This thermal property is similar to that of crystalline materials. Electron microscopy observations revealed the presence of nanocrystals embedded in the amorphous matrix of the IGZO films. The typical size of the nanocrystals was approximately 2–5 nm with the lattice distance of about 0.24–0.26 nm. These experimental results indicate that the nanocrystalline microstructure controls the heat conduction in the IGZO films.https://www.mdpi.com/2079-4991/11/6/1547IGZO thin filmthree-omega methodthermal conductivitynano crystallinitytransmission electron microscopy |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Rauf Khan Michitaka Ohtaki Satoshi Hata Koji Miyazaki Reiji Hattori |
spellingShingle |
Rauf Khan Michitaka Ohtaki Satoshi Hata Koji Miyazaki Reiji Hattori Thermal Conductivity of Nano-Crystallized Indium-Gallium-Zinc Oxide Thin Films Determined by Differential Three-Omega Method Nanomaterials IGZO thin film three-omega method thermal conductivity nano crystallinity transmission electron microscopy |
author_facet |
Rauf Khan Michitaka Ohtaki Satoshi Hata Koji Miyazaki Reiji Hattori |
author_sort |
Rauf Khan |
title |
Thermal Conductivity of Nano-Crystallized Indium-Gallium-Zinc Oxide Thin Films Determined by Differential Three-Omega Method |
title_short |
Thermal Conductivity of Nano-Crystallized Indium-Gallium-Zinc Oxide Thin Films Determined by Differential Three-Omega Method |
title_full |
Thermal Conductivity of Nano-Crystallized Indium-Gallium-Zinc Oxide Thin Films Determined by Differential Three-Omega Method |
title_fullStr |
Thermal Conductivity of Nano-Crystallized Indium-Gallium-Zinc Oxide Thin Films Determined by Differential Three-Omega Method |
title_full_unstemmed |
Thermal Conductivity of Nano-Crystallized Indium-Gallium-Zinc Oxide Thin Films Determined by Differential Three-Omega Method |
title_sort |
thermal conductivity of nano-crystallized indium-gallium-zinc oxide thin films determined by differential three-omega method |
publisher |
MDPI AG |
series |
Nanomaterials |
issn |
2079-4991 |
publishDate |
2021-06-01 |
description |
The temperature dependence thermal conductivity of the indium-gallium-zinc oxide (IGZO) thin films was investigated with the differential three-omega method for the clear demonstration of nanocrystallinity. The thin films were deposited on an alumina (α-Al<sub>2</sub>O<sub>3</sub>) substrate by direct current (DC) magnetron sputtering at different oxygen partial pressures ([PO<sub>2</sub>] = 0%, 10%, and 65%). Their thermal conductivities at room temperature were measured to be 1.65, 1.76, and 2.58 Wm<sup>−1</sup>K<sup>−1</sup>, respectively. The thermal conductivities decreased with an increase in the ambient measurement temperature. This thermal property is similar to that of crystalline materials. Electron microscopy observations revealed the presence of nanocrystals embedded in the amorphous matrix of the IGZO films. The typical size of the nanocrystals was approximately 2–5 nm with the lattice distance of about 0.24–0.26 nm. These experimental results indicate that the nanocrystalline microstructure controls the heat conduction in the IGZO films. |
topic |
IGZO thin film three-omega method thermal conductivity nano crystallinity transmission electron microscopy |
url |
https://www.mdpi.com/2079-4991/11/6/1547 |
work_keys_str_mv |
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