Self-assembling circuits using carbon nanotube molecules could replace silicon chips.
James Heath, of the University of California and colleagues have demonstrated that if one or both of two wires crossed at right angles are semiconducting, the junction can act like an electronic device such as a diode and each device can be switched on or off without affecting the others.

This proof of principle raises hopes that a nanotube lattice could form a computer memory, storing one bit of information at each junction. Such a circuit could potentially furnish a random-access memory with a storage density around 100,000 times greater than that of a Pentium chip.