Until recently, it has been known that fundamental physics limits the magnitude of electrical nanotube contacts to no less than 6.5 kΩ (their so-called quantum resistance) and that palladium electrodes help us to nearly achieve that limit with large-diameter (2–3 nm) nanotubes. This recent work finds that the thermal contact between nanotubes and their environment also shapes their electrical behaviour, particularly in high-current high-voltage situations, such as near breakdown.
A broad data set was analyzed and a trend was found between the breakdown voltage of nanotubes and their thermal contact to the environment. Interestingly, the breakdown voltage of long (>0.5 µm) nanotubes scales linearly with their length, while the breakdown voltage of short nanotubes appears to level off, or even increase for very short (<0.1 µm) samples. This is attributed to the role of the thermal and electrical contacts between nanotubes and their environment. Moreover, there appears to be a minimum breakdown voltage for samples close to approximately half a micron.
This work is among the first to highlight the importance of thermal coupling between one-dimensional conductors and their three-dimensional environment. The possibility of tuning this interaction can lead to, or optimize, a variety of interesting applications, such as more efficient thermoelectrics, nanotube heat sinks or nanotube fuse-based electrical circuits.