Thermal conductivity of amorphous Al2O3/ TiO2 nanolaminates deposited by atomic layer deposition

Saima Ali (Corresponding Author), Taneli Juntunen, Sakari Sintonen, Oili Ylivaara, Riikka Puurunen, Harri Lipsanen, Ilkka Tittonen, Simo-Pekka Hannula

Research output: Contribution to journalArticleScientificpeer-review

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Abstract

The thermophysical properties of Al2O3/TiO2 nanolaminates deposited by atomic layer deposition (ALD) are studied as a function of bilayer thickness and relative TiO2 content (0%- 100%) while the total nominal thickness of the nanolaminates was kept at 100 nm. Cross-plane thermal conductivity of the nanolaminates is measured at room temperature using the nanosecond transient thermoreflectance method. Based on the measurements, the nanolaminates have reduced thermal conductivity as compared to the pure amorphous thin films, suggesting that interfaces have a non-negligible effect on thermal transport in amorphous nanolaminates. For a fixed number of interfaces, we find that approximately equal material content of Al2O3 and TiO2 produces the lowest value of thermal conductivity. The thermal conductivity reduces with increasing interface density up to 0.4 nm?1, above which the thermal conductivity is found to be constant. The value of thermal interface resistance approximated by the use of diffuse mismatch model was found to be 0.45 m2KGW?1, and a comparative study employing this value supports the interpretation of non-negligible interface resistance affecting the overall thermal conductivity also in the amorphous limit. Finally, no clear trend in thermal conductivity values was found for nanolaminates grown at different deposition temperatures, suggesting that the temperature in the ALD process has a non-trivial while modest effect on the overall thermal conductivity in amorphous nanolaminates.
Original languageEnglish
Article number445704
JournalNanotechnology
Volume27
DOIs
Publication statusPublished - 2016
MoE publication typeA1 Journal article-refereed

Fingerprint

Atomic layer deposition
Thermal conductivity
Amorphous films
Temperature
Thermodynamic properties
Thin films

Keywords

  • thermal conductivity
  • Kapitza resistance
  • amorphous
  • nanolaminates
  • ALD

Cite this

Ali, Saima ; Juntunen, Taneli ; Sintonen, Sakari ; Ylivaara, Oili ; Puurunen, Riikka ; Lipsanen, Harri ; Tittonen, Ilkka ; Hannula, Simo-Pekka. / Thermal conductivity of amorphous Al2O3/ TiO2 nanolaminates deposited by atomic layer deposition. In: Nanotechnology. 2016 ; Vol. 27.
@article{5e821c4b22ff49048fda6519339d3b6c,
title = "Thermal conductivity of amorphous Al2O3/ TiO2 nanolaminates deposited by atomic layer deposition",
abstract = "The thermophysical properties of Al2O3/TiO2 nanolaminates deposited by atomic layer deposition (ALD) are studied as a function of bilayer thickness and relative TiO2 content (0{\%}- 100{\%}) while the total nominal thickness of the nanolaminates was kept at 100 nm. Cross-plane thermal conductivity of the nanolaminates is measured at room temperature using the nanosecond transient thermoreflectance method. Based on the measurements, the nanolaminates have reduced thermal conductivity as compared to the pure amorphous thin films, suggesting that interfaces have a non-negligible effect on thermal transport in amorphous nanolaminates. For a fixed number of interfaces, we find that approximately equal material content of Al2O3 and TiO2 produces the lowest value of thermal conductivity. The thermal conductivity reduces with increasing interface density up to 0.4 nm?1, above which the thermal conductivity is found to be constant. The value of thermal interface resistance approximated by the use of diffuse mismatch model was found to be 0.45 m2KGW?1, and a comparative study employing this value supports the interpretation of non-negligible interface resistance affecting the overall thermal conductivity also in the amorphous limit. Finally, no clear trend in thermal conductivity values was found for nanolaminates grown at different deposition temperatures, suggesting that the temperature in the ALD process has a non-trivial while modest effect on the overall thermal conductivity in amorphous nanolaminates.",
keywords = "thermal conductivity, Kapitza resistance, amorphous, nanolaminates, ALD",
author = "Saima Ali and Taneli Juntunen and Sakari Sintonen and Oili Ylivaara and Riikka Puurunen and Harri Lipsanen and Ilkka Tittonen and Simo-Pekka Hannula",
note = "Project 74717 MECHALD Project 102086 ALDCoE",
year = "2016",
doi = "10.1088/0957-4484/27/44/445704",
language = "English",
volume = "27",
journal = "Nanotechnology",
issn = "0957-4484",
publisher = "Institute of Physics IOP",

}

Ali, S, Juntunen, T, Sintonen, S, Ylivaara, O, Puurunen, R, Lipsanen, H, Tittonen, I & Hannula, S-P 2016, 'Thermal conductivity of amorphous Al2O3/ TiO2 nanolaminates deposited by atomic layer deposition', Nanotechnology, vol. 27, 445704. https://doi.org/10.1088/0957-4484/27/44/445704

Thermal conductivity of amorphous Al2O3/ TiO2 nanolaminates deposited by atomic layer deposition. / Ali, Saima (Corresponding Author); Juntunen, Taneli; Sintonen, Sakari; Ylivaara, Oili; Puurunen, Riikka; Lipsanen, Harri; Tittonen, Ilkka; Hannula, Simo-Pekka.

In: Nanotechnology, Vol. 27, 445704, 2016.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - Thermal conductivity of amorphous Al2O3/ TiO2 nanolaminates deposited by atomic layer deposition

AU - Ali, Saima

AU - Juntunen, Taneli

AU - Sintonen, Sakari

AU - Ylivaara, Oili

AU - Puurunen, Riikka

AU - Lipsanen, Harri

AU - Tittonen, Ilkka

AU - Hannula, Simo-Pekka

N1 - Project 74717 MECHALD Project 102086 ALDCoE

PY - 2016

Y1 - 2016

N2 - The thermophysical properties of Al2O3/TiO2 nanolaminates deposited by atomic layer deposition (ALD) are studied as a function of bilayer thickness and relative TiO2 content (0%- 100%) while the total nominal thickness of the nanolaminates was kept at 100 nm. Cross-plane thermal conductivity of the nanolaminates is measured at room temperature using the nanosecond transient thermoreflectance method. Based on the measurements, the nanolaminates have reduced thermal conductivity as compared to the pure amorphous thin films, suggesting that interfaces have a non-negligible effect on thermal transport in amorphous nanolaminates. For a fixed number of interfaces, we find that approximately equal material content of Al2O3 and TiO2 produces the lowest value of thermal conductivity. The thermal conductivity reduces with increasing interface density up to 0.4 nm?1, above which the thermal conductivity is found to be constant. The value of thermal interface resistance approximated by the use of diffuse mismatch model was found to be 0.45 m2KGW?1, and a comparative study employing this value supports the interpretation of non-negligible interface resistance affecting the overall thermal conductivity also in the amorphous limit. Finally, no clear trend in thermal conductivity values was found for nanolaminates grown at different deposition temperatures, suggesting that the temperature in the ALD process has a non-trivial while modest effect on the overall thermal conductivity in amorphous nanolaminates.

AB - The thermophysical properties of Al2O3/TiO2 nanolaminates deposited by atomic layer deposition (ALD) are studied as a function of bilayer thickness and relative TiO2 content (0%- 100%) while the total nominal thickness of the nanolaminates was kept at 100 nm. Cross-plane thermal conductivity of the nanolaminates is measured at room temperature using the nanosecond transient thermoreflectance method. Based on the measurements, the nanolaminates have reduced thermal conductivity as compared to the pure amorphous thin films, suggesting that interfaces have a non-negligible effect on thermal transport in amorphous nanolaminates. For a fixed number of interfaces, we find that approximately equal material content of Al2O3 and TiO2 produces the lowest value of thermal conductivity. The thermal conductivity reduces with increasing interface density up to 0.4 nm?1, above which the thermal conductivity is found to be constant. The value of thermal interface resistance approximated by the use of diffuse mismatch model was found to be 0.45 m2KGW?1, and a comparative study employing this value supports the interpretation of non-negligible interface resistance affecting the overall thermal conductivity also in the amorphous limit. Finally, no clear trend in thermal conductivity values was found for nanolaminates grown at different deposition temperatures, suggesting that the temperature in the ALD process has a non-trivial while modest effect on the overall thermal conductivity in amorphous nanolaminates.

KW - thermal conductivity

KW - Kapitza resistance

KW - amorphous

KW - nanolaminates

KW - ALD

U2 - 10.1088/0957-4484/27/44/445704

DO - 10.1088/0957-4484/27/44/445704

M3 - Article

VL - 27

JO - Nanotechnology

JF - Nanotechnology

SN - 0957-4484

M1 - 445704

ER -