Multilevel memory based on molecular devices

Multilevel molecular memory devices were proposed and demonstrated for nonvolatile data storage up to three bits (eight levels) per cell, in contrast to the standard one-bit-per-cell (two levels) technology. In the demonstration, charges were precisely placed at up to eight discrete levels in redox active molecules self-assembled on single-crystal semiconducting nanowire field-effect transistors. Gate voltage pulses and current sensing were used for writing and reading operations, respectively. Charge storage stability was tested up to retention of 600 h, as compared to the longest retention of a few hours previously reported for one-bit-per-cell molecular memories. (C) 2004 American Institute of Physics.