Electrical and optical characterization of molecular junctions
Abstract/Contents
- Abstract
- Electronic transport through molecules has been intensively studied in recent years, due to scientific interest in fundamental questions about charge transport and the technological promise of nanoscale circuitry. A variety of experimental platforms have been developed to electronically probe molecular junctions. However, it remains challenging to fabricate reliable electronic contacts to molecules, and the vast majority of molecular electronic architectures are not amenable to standard characterization techniques, such as optical spectroscopy. Interesting phenomena like switching and rectification are observed in molecular junctions. However, due to limited quantitative information about the junction, the mechanism remains unknown and many fundamental questions about electronic transport remain unanswered. The first part of the thesis will introduce the fabrication of Metal-Insulator-Metal (MIM) cross bar junctions using soft deposition technique. In this method, we softly deposit the premade metal contacts that are being supported with a polymer backing layer onto the organic layer. Using this method, we can efficiently fabricate large area, non-shorting devices, which are required for optical characterization of the molecular junctions. Having established a means of fabricating reliable molecular devices, we have investigated the switching mechanism in molecular junctions based on n-type semiconductor Perylene tetracarboxylic diimide (TE-PTCDI) molecules. Using Surface Plasmon Resonance Spectroscopy (SPRS) we have been able to perform simultaneous optical-electrical measurements to study the molecular behavior quantitatively. Using in- situ optical spectroscopy on active molecular junctions, we find that only a small fraction of the molecules are actually switching in the junction. Next, metal filament formation, a common phenomenon in thin film devices has been investigated. Metal filaments are observed to lead to non-molecular conductance variations in molecular junctions. Employing electrical and optical methods, the possible mechanisms responsible for the formation of metal filaments in the junction were studied. Finally, I present the results of our studies on the molecular rectification in C60- diamondoid hybrid molecules in large area junctions, as well as in smaller ensemble of molecules.
Description
| Type of resource | text |
|---|---|
| Form | electronic; electronic resource; remote |
| Extent | 1 online resource. |
| Publication date | 2011 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Associated with | Davani, Nazanin |
|---|---|
| Associated with | Stanford University, Department of Chemical Engineering |
| Primary advisor | Bent, Stacey |
| Primary advisor | Melosh, Nicholas A |
| Thesis advisor | Bent, Stacey |
| Thesis advisor | Melosh, Nicholas A |
| Thesis advisor | Bao, Zhenan |
| Advisor | Bao, Zhenan |
Subjects
| Genre | Theses |
|---|
Bibliographic information
| Statement of responsibility | Nazanin Davani. |
|---|---|
| Note | Submitted to the Department of Chemical Engineering. |
| Thesis | Thesis (Ph.D.)--Stanford University, 2011. |
| Location | electronic resource |
Access conditions
- Copyright
- © 2011 by Nazanin Davani
- License
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
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