AVS 53rd International Symposium
    Electronic Materials and Processing Friday Sessions
       Session EM-FrM

Paper EM-FrM4
Switching and Conductance Peaks in Metal-Molecule-Silicon Devices with Nitro-Containing Molecular Layers

Friday, November 17, 2006, 9:00 am, Room 2001

Session: Molecular Electronics
Presenter: A.D. Scott, Purdue University
Authors: A.D. Scott, Purdue University
D.B. Janes, Purdue University
Correspondent: Click to Email
Recently there has been a large amount of interest in developing molecular electronics for miniaturization and enhancing functionality of electronic devices. Interesting transport features have been observed in metal-molecule-metal devices containing nitro-substituted species.@footnote 1@ Silicon contacts to molecular devices offer advantages over metal contacts due to the covalent nature of the molecular attachment, the technological relevance of silicon, and the ability to tune the electrical properties of the contact through doping. In this study, we present interesting transport features observed in metal-molecule-silicon devices with nitro-containing molecular layers. These devices exhibit interesting transport behavior that varies with molecular species used and substrate doping. Devices with nitrobenzene layers on p+ Si substrates exhibit bistable switching in 63% of devices. This behavior has been characterized using current-voltage measurements and current vs. time measurements of switching transients. The voltage threshold at which switching takes place is 0.9±0.15 V and the ratio of on-current to off-current is approximately 10. Devices with 2-methyl 4-nitrobenzene layers on n Si exhibit non-ideal current-voltage behavior and show peaks in the conductance-voltage curves for all devices measured. The conductance peak occurs at 0.9V forward bias. It has been observed both by numerically differentiating DC current-voltage curves and by AC conductance measurements utilizing lock-in detection. Similar devices with molecular layers that do not contain nitro headgroups and those with different substrate dopings do not exhibit these features. @FootnoteText@ @footnote 1@ Chen J, Reed MA, Rawlett AM, Tour JM (1999) Large On-Off Ratios and Negative Differential Resistance in a Molecular Electronic Device. Science 286: 1550-1552.