from the current-events dept.
Adding to the recent spate of advances in molecular electronics research, two important papers on the use of carbon nanotubes to form electronic devices and circuits appeared in the 9 November 2001 issue of Science.
- Cees Dekker and co-workers at the University of Delft in the Netherlands report they have demonstrated logic circuits with field-effect transistors based on single carbon nanotubes. The transistors show favorable device characteristics such as high gain, a large on-off ratio, and room-temperature operation. The team was also able to demonstrate one-, two-, and three-transistor circuits that exhibit a range of digital logic operations, such as an inverter, a logic NOR, a static random-access memory cell, and an ac ring oscillator.
- Charles Lieber (recipient of the 2001 Feynman Prize in Nanotechnology for experimental work) and his research team at Harvard report a "bottom-up" approach in which functional device elements and element arrays are assembled from solution through the use of electronically well-defined semiconductor nanowire building blocks. Crossed nanowire junctions and junction arrays can be assembled with controllable electrical characteristics. The junctions can be used to create integrated nanoscale field-effect transistor arrays with nanowires as both the conducting channel and gate electrode. Nanowire junction arrays have been configured as OR, AND, and NOR logic-gate structures with substantial gain and have been used to implement basic computation.
Additional details is available in an article from the New York Times ("Nanowires May Lead to Superfast Computer Chips", 9 November 2001) and an item on the Nature Science Update website ("A little logic goes a long way", by Philip Ball, 9 November 2001). And Charles Lieberís work was the focus of an article in the November-December 2001 issue of Harvard Magazine ("Liquid Computing", by J. Shaw).