Highly reliable carbon nanotube transistors with patterned gates and molecular gate dielectric

The prospect of realizing nanoscale transistors using individual semiconducting carbon nanotubes offers enormous potential, both as an alternative to silicon technology beyond conventional scaling limits and as a way to implement high-speed devices and circuits on flexible substrates. A significant challenge is the realization of low-voltage nanotube transistors with individually addressable gate electrodes that display large transconductance, steep subthreshold swing, and large on/off ratio. Their integration into circuits with large signal gain and good stability still needs to be demonstrated. Here, we demonstrate that these important goals can be achieved with the help of a bottom-gate device structure that combines patterned metal gates with a thin gate dielectric based on a molecular self-assembled monolayer. The obtained transistors operate with a gate-source voltage of 1 V and have a transconductance of 5 microS, a subthreshold swing of 68 mV/decade, and an on/off ratio of 10(7). To verify the excellent operational and shelf life stability, we show that the device performance does not degrade during 10,000 switching cycles and during storage under ambient conditions for more than 300 days. We also demonstrate that the device structure allows the implementation of unipolar logic circuits with good switching characteristics.