Ravi Pandya
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Ravi Pandya   software | nanotechnology | economics


2007 11 10

2004 10 09 08 07 06

2003 04 02 01

2002 12 11 10 09 08

2001 11


Ravi Pandya
Cloud Computing Futures
ravip at microsoft.com

00-02 Covalent
97-00 EverythingOffice
96-97 Jango
93-96 NetManage
89-93 Xanadu
88-89 Hypercube
84,85 Xerox PARC
83-89 University of Toronto, Math
86-87 George Brown College, Dance
95-Foresight Institute
97-Institute for Molecular Manufacturing


The opinions expressed here are purely my own, and do not reflect the policy of my employer.

Sat 18 Jan 2003

Molecular Electronics at HP

I went to see a great lecture this week at UW Nano by Duncan Stewart from the molecular electronics group at HP Labs. They have a great multi-disciplinary group there, with computer architecture, physical chemistry, organic synthesis, polymers, electrochemistry, materials science, and experimental & theoretical physics. They're using a cross bar architecture with Langmuir-Blodget molecular monolayer between a grid of contacts in a crossbar architecture. Not only have they built a 256-bit memory (to store "HPinvent" :-) but they have also configured it as an FPGA cell with 2-bit multiplexers on the input and output, and a lookup table in between. All this in a square micron!

One of the interesting tidbits was from Stewart's own work in trying to characterize and understand the actual operation of the device. They first tried a monolayer of Jim Heath's fancy rotaxane molecules with a movable ring system acting as a switch. The I-V curves show a nice negative differential resistance that can be used for switching and diode behavior. OK, great, it's the little ring moving along the backbone of the rotaxane. But then they tried a control substance - eicosanoic acid, "basically floor wax". The numbers were a little different, but qualitatively the behavior was the same.

So it's not the material, but probably some interface effect. But what is it? This is a real puzzle, and it's not solved yet. The best hypothesis so far is temperature dependent tunneling effects at the metal-organic interface, pretty much independent of the particular organic species. It'll be interesting to see further developments...

10:31 #

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