单根单壁碳纳米管导热系数随长度变化尺度效应的实验和理论

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. 关键词： ω法')" href="#">3ω法 单壁碳纳米管 导热系数 二阶3-声子过程

Experimental and theoretical study of the length-dependent thermal conductivity of individual single-walled carbon nanotubes

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—7μm) 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 175nm. Both the measurement and the prediction show the scale effect of the length on the thermal conductivity of SWNTs.