中国物理B ›› 2009, Vol. 18 ›› Issue (5): 2035-2040.doi: 10.1088/1674-1056/18/5/051

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Different effects of grain boundary scattering on chargeand heat transport in polycrystalline platinum and goldnanofilms

TakahashiKoji1, 马维刚2, 王海东2, 张兴2   

  1. (1)Graduate School of Engineering, Kyushu University, Fukuoka 819-0395, Japan; (2)Key Laboratory for Thermal Science and Power Engineering of Ministry of Education,Department of Engineering Mechanics, Tsinghua University, Beijing 100084, China
  • 收稿日期:2008-10-07 修回日期:2008-11-10 出版日期:2009-05-20 发布日期:2009-05-20
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant Nos 50676046 and 50730006).

Different effects of grain boundary scattering on charge and heat transport in polycrystalline platinum and gold nanofilms

Ma Wei-Gang(马维刚)a), Wang Hai-Dong(王海东)a), Zhang Xing(张兴)a)†, and Takahashi Kojib)   

  1. a Key Laboratory for Thermal Science and Power Engineering of Ministry of Education,Department of Engineering Mechanics, Tsinghua University, Beijing 100084, China; b Graduate School of Engineering, Kyushu University, Fukuoka 819-0395, Japan
  • Received:2008-10-07 Revised:2008-11-10 Online:2009-05-20 Published:2009-05-20
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant Nos 50676046 and 50730006).

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摘要： The in-plane electrical and thermal conductivities of several polycrystalline platinum and gold nanofilms with different thicknesses are measured in a temperature range between the boiling point of liquid nitrogen (77K) and room temperature by using the direct current heating method. The result shows that both the electrical and thermal conductivities of the nanofilms reduce greatly compared with their corresponding bulk values. However, the electrical conductivity drop is considerably greater than the thermal conductivity drop, which indicates that the influence of the internal grain boundary on heat transport is different from that of charge transport, hence leading to the violation of the Wiedemann--Franz law. We build an electron relaxation model based on Matthiessen's rule to analyse the thermal conductivity and employ the Mayadas & Shatzkes theory to analyse the electrical conductivity. Moreover, a modified Wiedemann--Franz law is provided in this paper, the obtained results from which are in good agreement with the experimental data.

关键词: polycrystalline nanofilm, grain boundary scattering, thermal and electrical conductivities, Wiedemann--Franz law

Abstract: The in-plane electrical and thermal conductivities of several polycrystalline platinum and gold nanofilms with different thicknesses are measured in a temperature range between the boiling point of liquid nitrogen (77K) and room temperature by using the direct current heating method. The result shows that both the electrical and thermal conductivities of the nanofilms reduce greatly compared with their corresponding bulk values. However, the electrical conductivity drop is considerably greater than the thermal conductivity drop, which indicates that the influence of the internal grain boundary on heat transport is different from that of charge transport, hence leading to the violation of the Wiedemann--Franz law. We build an electron relaxation model based on Matthiessen's rule to analyse the thermal conductivity and employ the Mayadas & Shatzkes theory to analyse the electrical conductivity. Moreover, a modified Wiedemann--Franz law is provided in this paper, the obtained results from which are in good agreement with the experimental data.

Key words: polycrystalline nanofilm, grain boundary scattering, thermal and electrical conductivities, Wiedemann--Franz law

中图分类号:  (Metal and metallic alloys)

  • 73.61.At
72.15.Eb (Electrical and thermal conduction in crystalline metals and alloys) 73.63.-b (Electronic transport in nanoscale materials and structures) 61.72.Mm (Grain and twin boundaries)