Impact of thermal boundary conductances on power dissipation and electrical breakdown of carbon nanotube network transistors

We study the impact of thermal boundary conductance (TBC) at carbon nanotube (CNT)-substrate interfaces and CNT junctions on power dissipation and breakdown in CNT network based thin film transistors (CN-TFTs). Comparison of our results from an electro-thermal transport model of CN-TFTs to experimental measurements of power dissipation and temperature profiles allows us to estimate the average CNT-SiO₂ TBC as g ∼ 0.16 Wm^-1 K ^-1 and the TBC at CNT junctions as G_C ∼ 2.4 pWK ^-1. We find the peak power dissipation in CN-TFTs is more strongly correlated to the TBC of the CNT-substrate interface than to the TBC at CNT junctions. Molecular dynamics simulations of crossed CNT junctions also reveal that the top CNT is buckled over ∼30 nm lengths, losing direct contact with the substrate and creating highly localized hot-spots. Our results provide new insights into CNT network properties which can be engineered to enhance performance of CN-TFTs for macro and flexible electronics applications.