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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Main Authors: Rauf Khan, Michitaka Ohtaki, Satoshi Hata, Koji Miyazaki, Reiji Hattori
Format: Article
Language:English
Published: MDPI AG 2021-06-01
Series:Nanomaterials
Subjects:
Online Access:https://www.mdpi.com/2079-4991/11/6/1547
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spelling 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
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AT michitakaohtaki thermalconductivityofnanocrystallizedindiumgalliumzincoxidethinfilmsdeterminedbydifferentialthreeomegamethod
AT satoshihata thermalconductivityofnanocrystallizedindiumgalliumzincoxidethinfilmsdeterminedbydifferentialthreeomegamethod
AT kojimiyazaki thermalconductivityofnanocrystallizedindiumgalliumzincoxidethinfilmsdeterminedbydifferentialthreeomegamethod
AT reijihattori thermalconductivityofnanocrystallizedindiumgalliumzincoxidethinfilmsdeterminedbydifferentialthreeomegamethod
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