The thermal transport at the carbon nanotube (CNT) interfaces such as CNT-oxide and CNT-CNT junctions can significantly impact the device performance and reliability of nanotube network based thin-film transistors. For an example, the high electrical and thermal resistance at CNT junctions can cause hot spots, inefficient heat removal or even breakdown of CNTs. This paper presents a molecular dynamics based computational study of the heat dissipation at CNT-CNT junctions supported on silicon dioxide substrate. The breakdown of CNTs at high power densities and heat dissipation mechanism at CNT-CNT-oxide junctions is analyzed for different contact structures. It has been observed that at similar power densities the temperature in hanging CNTs can be hundreds of degree higher and can reach to breakdown temperature compared to the CNTs well-contacted with the substrate. The energy transfer in different frequency bands across the CNT-CNT-oxide contact was investigated using spectral energy density method. The lower CNT in the supported CNT-CNT junctions blocks the direct transport of high frequency phonons of top CNT to the oxide substrate.
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