Moving transistors downscale One option for extending the performance of complementary metal-oxide semiconductor (CMOS) devices based on silicon technology is to use semiconducting carbon nanotubes as the gates. Qiu et al. fabricated top-gated carbon nanotube field-effect transistors with a gate length of 5 nm. Thin graphene contacts helped maintain electrostatic control. A scaling trend study revealed that, compared with silicon CMOS devices, the nanotube-based devices operated much faster and at much lower supply voltage, and they approached the limit of one electron per switching operation. Science , this issue p. 271