Ballistic to diffusive crossover of heat flow in graphene ribbons

被引：0

作者：

Myung-Ho Bae

Zuanyi Li

Zlatan Aksamija

Pierre N Martin

Feng Xiong

Zhun-Yong Ong

Irena Knezevic

Eric Pop

机构：

[1] Micro and Nanotechnology Lab,Department of Electrical and Computer Engineering

[2] University of Illinois at Urbana-Champaign,Department of Physics

[3] University of Illinois at Urbana-Champaign,Department of Electrical and Computer Engineering

[4] University of Illinois at Urbana-Champaign,undefined

[5] University of Wisconsin-Madison,undefined

[6] Beckman Institute,undefined

[7] University of Illinois at Urbana-Champaign,undefined

[8] Present address: Korea Research Institute of Standards and Science,undefined

[9] Daejeon 305-340,undefined

[10] Republic of Korea,undefined

来源：

Nature Communications | / 4卷

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摘要：

Heat flow in nanomaterials is an important area of study, with both fundamental and technological implications. However, little is known about heat flow in two-dimensional devices or interconnects with dimensions comparable to the phonon mean free path. Here we find that short, quarter-micron graphene samples reach ~35% of the ballistic thermal conductance limit up to room temperature, enabled by the relatively large phonon mean free path (~100 nm) in substrate-supported graphene. In contrast, patterning similar samples into nanoribbons leads to a diffusive heat-flow regime that is controlled by ribbon width and edge disorder. In the edge-controlled regime, the graphene nanoribbon thermal conductivity scales with width approximately as ~W1.80.3, being about 100 W m−1 K−1 in 65-nm-wide graphene nanoribbons, at room temperature. These results show how manipulation oftwo-dimensional device dimensions and edges can be used to achieve full control of their heat-carrying properties, approaching fundamentally limited upper or lower bounds.

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