2005 APS March Meeting
Monday–Friday, March 21–25, 2005;
Los Angeles, CA
Session P35: Molecular Electronics I
11:15 AM–2:15 PM,
Wednesday, March 23, 2005
LACC
Room: 511B
Sponsoring
Units:
DCP DMP FIAP
Chair: Cherie Kagan, IBM, TJ Watson
Abstract ID: BAPS.2005.MAR.P35.3
Abstract: P35.00003 : Electronic Conduction and Switching in Metal / Molecule / Metal Structures
12:03 PM–12:39 PM
Preview Abstract
Abstract
Author:
Duncan Stewart
(Hewlett-Packard Laboratories, Palo Alto, CA USA)
We report both physical and electrical characterization of several metal /
organic monolayer / metal device structures which display electrical
switching behavior. Devices comprised a planar lower metal electrode of
aluminum (Al) or platinum (Pt), a Langmuir-Blodgett or self-assembled
organic alkane monolayer, and an evaporated metal upper electrode of
titanium (Ti) or platinum. Single crosspoint devices of area 1600
nm$^{2}$--100 um$^{2 }$incorporated 10$^{3}$-10$^{7}$ molecules in parallel.
Electrode surfaces, monolayer structure, and electrode-monolayer
interactions were very sensitive to sample preparation. X-ray photoelectron
spectroscopy (XPS) indicated that the thickness and stoichiometry of PtOx
and TiOx species at both metal-organic interfaces were strongly affected by
process conditions including deposition pressures and plasma treatments.
Infra-red spectroscopy (RAIR) using ultra-flat template-stripped metal
substrates showed that the physical structure of the monolayer was similarly
sensitive to nanometer-scale electrode roughness.
Electrical conductance hysteresis was observed in Al/monolayer/Ti and
Pt/monolayer/Ti devices. Local-pressure modulated atomic force microscopy
(AFM) suggested that the electrical hysteresis was dominated by one or two
nano-conduction channels $<$30 nm in diameter. The asymmetric, reversible
conductance switching observed remains inconsistent with a simple dielectric
breakdown process. Instead, for each electrode system we suggest either an
interface electrochemical process or a reversible nanoparticle growth {\&}
dissolution as primarily responsible for the observed electrical switching.
Technology proof-of-principle demonstrations of ultra-dense nanoscale memory
and logic integrated crossbar circuits, including latch circuits showing
signal restoration, have successfully utilized these organic monolayer
structures.
To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2005.MAR.P35.3