Layers promise cheap storage

Princeton University and Hewlett-Packard Laboratories researchers have constructed a very low cost data storage device from plastic and silicon that can potentially store one hundred megabits of information per square centimeter.

The device is made from thin-film silicon electronics covered with a conductive polymer coating. The coating, dubbed Pedot, was first used as an antistatic coating for photographic film and is also used as a transparent electric contact for some types of video displays.

The researchers discovered that the material is conductive only at low voltages, and permanently loses its conductivity -- like a blown fuse -- when exposed to higher voltages. Tiny squares of conducting and non-conducting Pedot can represent the ones and zeros of computer information, and millions can be wired into a layered grid of circuits. Such memory can be read by sending a low voltage through all the squares and noting those that conduct and those that do not.

The researchers' device combines attributes of solid-state silicon memory devices and plastic storage devices like CDs. The method to be used to make a memory card that has no moving parts and can be written to once, but accessed many times.

The device could probably be made cheaply enough for one-time-use applications, according to the researchers.

The memory devices could be commercially viable in five years, according to the researchers. The work appeared in the October 12, 2003 issue of Nature.