AVS 51st International Symposium
    Organic Films and Devices Thursday Sessions
       Session OF+NS-ThM

Paper OF+NS-ThM2
Room Temperature Molecular Memory Observed from a Nanowell Device

Thursday, November 18, 2004, 8:40 am, Room 304C

Session: Molecular Electronics
Presenter: N. Majumdar, University of Virginia
Authors: N. Gergel, University of Virginia
N. Majumdar, University of Virginia
K. Keyvanfar, University of Virgina
N. Swami, University of Virgina
L.R. Harriott, University of Virginia
J.C. Bean, University of Virginia
Correspondent: Click to Email
Researchers are debating whether the electrical switching behavior observed from some molecular devices can be attributed exclusively to the molecules@footnote 1@. We tested an OPE molecule with a nitro side group. This molecule showed electrical switching behavior when tested in a nanowell device at room temperature. This behavior was not seen when testing a simple conjugated molecule that lacked the nitro group. The test was performed in a nanowell device that consisted of a monolayer of molecules self-assembled on an area of gold 10-40 nm in diameter and capped with titanium and gold@footnote 2@. The I-V characteristics of the nitro molecule clearly showed two distinct conductivity states with a current ratio of 5 to 1 at room temperature. The experimental data showed that at a particular threshold voltage, the output current changed from a high current state to a low current state. This change in state was reversed with the opposite applied voltage. Hysteresis was not observed when testing a similar conjugated molecule without the nitro group at room temperature. Thus, the switching behavior could be attributed to changes in the conductivity of the nitro molecules due to the applied voltage. Other groups have reported seeing negative differential resistance behavior (NDR) in the I-V characteristics of the nitro molecule@footnote 3@. We saw similar peaks to those reported. However, our investigations indicate that this behavior is not reversible without the application of a negative threshold voltage. For this reason, these molecules may not be suitable for classic NDR circuits (e.g. Goto pairs@footnote 4@). This hysteretic behavior may nevertheless have device potential. @FootnoteText@ @footnote 1@ R.F. Forrest, Science 302, 556 (2003).@footnote 2@N. Majumdar, et al, submitted to J. Vac. Sci. Tech.@footnote 3@ M.A. Reed, et al, Applied Physics Letters 78, 3735 (2001).@footnote 4@ G. Rose, and M. Stan, IEEE NANO, San Fransisco, Aug (2003).