Voskanian Norvik, Olsson Eva, Cumings John
Department of Physics, Chalmers University of Technology, 412 96, Gothenburg, Sweden.
Department of Materials Science and Engineering, University of Maryland, College Park, Maryland, 20740, USA.
Sci Rep. 2019 Jul 25;9(1):10785. doi: 10.1038/s41598-019-46944-9.
We study heat dissipation of a multi-wall carbon nanotube (MWCNT) device fabricated from two crossed nanotubes on a SiN substrate under the influence of a constant (DC) electric bias. By monitoring the temperature of the substrate, we observe negligible Joule heating within the nanotube lattice itself and instead heating occurs in the insulating substrate directly via a remote-scattering heating effect. Using finite element analysis, we estimate a remote heating parameter, β, as the ratio of the power dissipated directly in the substrate to the total power applied. The extracted parameters show two distinct bias ranges; a low bias regime where about 85% of the power is dissipated directly into the substrate and a high bias regime where β decreases, indicating the onset of traditional Joule heating within the nanotube. Analysis shows that this reduction is consistent with enhanced scattering of charge carriers by optical phonons within the nanotube. The results provide insights into heat dissipation mechanisms of Joule heated nanotube devices that are more complex than a simple heat dissipation mechanism dominated by acoustic phonons, which opens new possibilities for engineering nanoelectronics with improved thermal management.
我们研究了在恒定（直流）电偏压影响下，由氮化硅衬底上两根交叉纳米管制成的多壁碳纳米管（MWCNT）器件的热耗散情况。通过监测衬底温度，我们观察到纳米管晶格本身的焦耳热可忽略不计，相反，热量是通过远程散射热效应直接在绝缘衬底中产生的。使用有限元分析，我们估计了一个远程加热参数β，即直接在衬底中耗散的功率与施加的总功率之比。提取的参数显示出两个不同的偏压范围：一个低偏压 regime，其中约85%的功率直接耗散到衬底中；一个高偏压 regime，其中β降低，表明纳米管内传统焦耳热的开始。分析表明，这种降低与纳米管内光学声子对电荷载流子散射的增强一致。这些结果为焦耳加热纳米管器件的热耗散机制提供了见解，该机制比由声学声子主导的简单热耗散机制更为复杂，这为具有改进热管理的工程纳米电子学开辟了新的可能性。
