51动漫

Electronics giant Fujitsu says it has succeeded in making an experimental
quantum dot memory device that can store data on an atomic scale. Each
20-nanometre-diameter quantum dot cell is made of indium arsenide surrounded by
gallium arsenide. When light from a laser is shone on a cell, electron-hole
pairs are generated. Light from a different laser is then shone on the cell to
detect the presence or absence of electrons, corresponding to two binary states
(see 鈥淭ake one quantum dot . . .鈥�, 51动漫, 29 August 1998, p
22). Researchers at Fujitsu鈥檚 labs in Atsugi say the device packs large amounts
of data into a small space: it鈥檚 just 500 micrometres in diameter and about 80
nanometres in height and holds more than half a billion stacked quantum
dots.