Three teams have independently fabricated semiconductor nanowire superlattices: complex woven structures of otherwise incompatible materials. The ability to construct such structures may lead to nano bar codes, novel waveguides, injection lasers and nanoscale LEDs.In the Feb. 7 issue of Nature, researchers at Harvard University in Cambridge, Mass., described how they used laser-assisted catalytic growth and chemical vapor deposition to produce superlattices of GaAs/GaP, n-Si/p-Si and n-InP/p-InP. The team also reports the performance of an LED constructed of an InP lattice, which could have applications as a single-photon source in quantum cryptography and computing.Reporting in the Feb. 13 issue of Nano Letters, researchers at the University of California in Berkeley and at Lund University in Sweden described two methods to produce the nanowire superlattices. The former employed laser-assisted growth to yield lattices of Si/SiGe, which could find applications in wireless telecommunications. The latter constructed InAs/InP structures with atomically perfect interfaces using molecular beam epitaxy.