中文摘要：

考虑纳米碳管与基体之间的热损失,采用四焊盘-3ω法测量了室温下基体表面不同长度单根单壁碳纳米管（SWNT）的导热系数.SWNT的导热系数在测试长度范围（0·5—7μm）内随长度的增大而增大,增加的幅度逐渐减小.考虑二阶3-声子过程的影响,采用改进的WV模型预测了SWNT导热系数随长度的变化规律.理论预测的声子平均自由程-175nm.导热系数的测量结果与室温下不同长度SWNT的实验结果相吻合.理论预测结果与实验结果均说明SWNT导热系数随长度变化具有尺度效应.

英文摘要：

We report measurements on the length-dependent thermal conductivity of individual single-walled carbon nanotubes （SWNTs） on a substrate using a four-pad 3ω method with the consideration of heat loss between the sample and substrate. An increase in thermal conductivity with length （0.5—7 μm） was observed at room temperature. The length-dependence of thermal conductivity was theoretically predicted by the modified WV model with consideration of second order -3-phonon process. The predicted phonon mean free path is about 175 nm. Both the measurement and the prediction show the scale effect of the length on the thermal conductivity of SWNTs.