Superlattices

The past decade has seen an explosive growth of interest in a new type of semiconductor called a superlattice. Made by sandwiching together thin layers of different semiconducting materials into a single crystal, a superlattice is a completely synthetic material. Superlattice properties such as the band gap may be tailored to suit particular applications, eg a laser whose output is tuned to suit optical fibres. Completely new devices such as a solid-state photomultiplier have been suggested and novel and unexpected physical phenomena have been observed.