A semiconductor device in which discrete packets of charge are transferred from one location to the next. Such devices can be used for the short-term storage of charge in a particular location provided that the storage time is short compared with the recombination time in the material. Several different types of charge-transfer device exist, the main classifications being charge-coupled devices and bucket-brigade devices. Applications of charge-transfer devices include short-term memory systems, shift registers, and imaging systems. Information is usually only available for serial access.