Thermal transport evolution due to nanostructural transformations in Ga-doped indium-tin-oxide thin films
| Autor: | Ghenadii Korotcenkov, Alexandr I. Cocemasov, Denis L. Nika, Vladimir Brinzari, Jong Seok Lee, Sergiu Vatavu, Do-Gyeom Jeong |
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| Jazyk: | angličtina |
| Rok vydání: | 2021 |
| Předmět: |
Materials science
Phonon thin film General Chemical Engineering Analytical chemistry FOS: Physical sciences Time-domain thermoreflectance 02 engineering and technology 010402 general chemistry 01 natural sciences Article thermal transport indium-tin-oxide thermoelectrics Thermal conductivity Thermoelectric effect Mesoscale and Nanoscale Physics (cond-mat.mes-hall) General Materials Science Thin film QD1-999 Condensed Matter - Materials Science Condensed Matter - Mesoscale and Nanoscale Physics Doping Materials Science (cond-mat.mtrl-sci) 021001 nanoscience & nanotechnology Nanocrystalline material 0104 chemical sciences Indium tin oxide Chemistry 0210 nano-technology |
| Zdroj: | Nanomaterials Nanomaterials, Vol 11, Iss 1126, p 1126 (2021) Nanomaterials; Volume 11; Issue 5; Pages: 1126 |
| Popis: | We report on a comprehensive theoretical and experimental investigation of thermal conductivity in indium-tin-oxide (ITO) thin films with various Ga concentrations (0-30 at. %) deposited by spray pyrolysis technique. X-Ray diffraction (XRD) and scanning electron microscopy have shown a structural transformation in the range 15-20 at. % Ga from the nanocrystalline to the amorphous phase. Room temperature femtosecond time domain thermoreflectance measurements showed nonlinear decrease of thermal conductivity in the range 2.0-0.5 W/(m K) depending on Ga doping level. Comparing density functional theory calculations with XRD data it was found that Ga atoms substitute In atoms in the ITO nanocrystals retaining Ia-3 space group symmetry. The calculated phonon dispersion relations revealed that Ga doping leads to the appearance of hybridized metal atom vibrations with avoided-crossing behavior. These hybridized vibrations possess shortened mean free paths and are the main reason behind the thermal conductivity drop in nanocrystalline phase. An evolution from propagative to diffusive phonon thermal transport in ITO:Ga with 15-20 at. % of Ga was established. The suppressed thermal conductivity of ITO:Ga thin films deposited by spray pyrolysis may be crucial for their thermoelectric applications. 21 pages, 8 figures |
| Databáze: | OpenAIRE |
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