Thermal Conductivity Comparison of Indium Gallium Zinc Oxide Thin Films: Dependence on Temperature, Crystallinity, and Porosity
The cross-plane thermal conductivity of InGaZnO (IGZO) thin films was measured using the 3ω technique from 18 to 300 K. The studied morphologies include amorphous (a-IGZO), semicrystalline (semi-c-IGZO), and c-axis-aligned single-crystal-like IGZO (c-IGZO) grown by pulsed laser deposition (PLD) as well as a-IGZO deposited by sputtering and by solution combustion processing. The atomic structures of the amorphous and crystalline films were simulated with ab initio molecular dynamics. The film quality and texturing information was assessed by X-ray diffraction and grazing incidence wide-angle X-ray scattering. X-ray reflectivity was also conducted to quantify film densities and porosities. All the high-density films exhibit an empirical power-law temperature dependence of the thermal conductivity K ~ T.06 in the specified temperature range. Among the PLD dense films, semi-c-IGZO exhibits the highest thermal conductivity, remarkably exceeding both films with more order (c-IGZO) and with less order (a-IGZO) by a factor of 4. The less dense combustion-synthesized films, on the other hand, exhibited lower thermal conductivity, quantitatively consistent with a porous film using either an effective medium or percolation model. All samples are consistent with the porosity-adapted Cahill-Pohl (p-CP) model of minimum thermal conductivity.
B. Cui and L. Zeng and D. Keane and M. J. Bedzyk and D. B. Buchholz and R. P. Chang and X. Yu and J. Smith and T. J. Marks and Y. Xia and A. F. Facchetti and J. E. Medvedeva and M. Grayson, "Thermal Conductivity Comparison of Indium Gallium Zinc Oxide Thin Films: Dependence on Temperature, Crystallinity, and Porosity," Journal of Physical Chemistry C, vol. 120, no. 14, pp. 7467-7475, American Chemical Society (ACS), Jan 2016.
The definitive version is available at http://dx.doi.org/10.1021/acs.jpcc.5b12105
Center for High Performance Computing Research
Keywords and Phrases
Amorphous Films; Combustion; Crystal Atomic Structure; Deposition; Molecular Dynamics; Oxide Films; Porosity; Pulsed Laser Deposition; Semiconducting Indium Compounds; Single Crystals; Solvents; Temperature Distribution; Thermal Conductivity of Solids; Thin Films; X Ray Diffraction; X Ray Scattering; Ab Initio Molecular Dynamics; High-Density Films; Indium Gallium Zinc Oxides; Percolation Models; Solution Combustion; Temperature Dependence; Temperature Range; X Ray Reflectivity; Thermal Conductivity
International Standard Serial Number (ISSN)
Article - Journal
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