Temperature Dependence of Electrical and Thermal Conduction in Single Silver Nanowire
Iowa State University of Science and Technology Ames United States
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In this work, the thermal and electrical transport in an individual silver nanowire is characterized down to 35 K for in-depth understanding of the strong structural defect induced electron scattering. The results indicate that, at room temperature, the electrical resistivity increases by around 4 folds from that of bulk silver. The Debye temperature151 K of the silver nanowire is found 36 lower than that 235 K of bulk silver, confirming strong phonon softening. At room temperature, the thermal conductivity is reduced by 55 from that of bulk silver. This reduction becomes larger as the temperature goes down. To explain the opposite trends of thermal conductivity temperature T of silver nanowire and bulk silver, a unified thermal resistivity is used to elucidate the electron scattering mechanism. A large residual value is observed for silver nanowire while that of the bulk silver is almost zero. The same T trend proposes that the silver nanowire and bulk silver share the similar phonon-electron scattering mechanism for thermal transport. Due to phonon-assisted electron energy transfer across grain boundaries, the Lorenz number of the silver nanowire is found much larger than that of bulk silver and decreases with decreasing temperature.