Charge transport in molecular junctions with soft contacts
Abstract/Contents
- Abstract
- This thesis describes a novel method to fabricate individually addressable molecular junctions of self-assembled monolayers (SAMs) and presents a series of molecular transport measurements taken with these devices. The results of these experiments are analyzed in terms of a general model applicable across a wide range of temperatures, biases and molecular species. The molecular junctions presented in this work exhibit the desired characteristics of nanoscale resolution, high yield and low device-to-device variation. Soft conductive polymer top contacts virtually eliminate shorts associated with diffusion of metal top contacts. We improve several features of previous soft contact devices and demonstrate an order of magnitude reduction in device area. We implement an inorganic dielectric layer with features defined by e-beam lithography and dry etching. We exchange the aqueous PEDOT:PSS conductive polymer used in prior devices for Aedotron P, a low-viscosity, amphiphilic polymer, allowing incorporation of self-assembled monolayers with either hydrophobic or hydrophilic termination with the same junction geometry and materials. We demonstrate the adaptability of this new design by presenting transport measurements on SAMs composed of alkanethiols with methyl, thiol, carboxyl, and azide terminations. We establish that the observed tunnel-barrier behavior is primarily a function of monolayer thickness, independent of the terminal group's hydrophilicity and present a model of the device conductivity as a product of several transmission coefficients. We investigate the temperature-dependence of transport, unique to polymer-contacted molecular junctions, and show that the behavior can be explained primarily as a function of transmission through the polymer layer. Finally, we study transport through mixed and homogenous monolayers of conjugated species, revealing the limits of Aedotron P as a contact material.
Description
| Type of resource | text |
|---|---|
| Form | electronic; electronic resource; remote |
| Extent | 1 online resource. |
| Publication date | 2012 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Associated with | Neuhausen, Alexander Benjamin |
|---|---|
| Associated with | Stanford University, Department of Electrical Engineering |
| Primary advisor | Goldhaber-Gordon, David, 1972- |
| Thesis advisor | Goldhaber-Gordon, David, 1972- |
| Thesis advisor | Bent, Stacey |
| Thesis advisor | Chidsey, Christopher E. D. (Christopher Elisha Dunn) |
| Advisor | Bent, Stacey |
| Advisor | Chidsey, Christopher E. D. (Christopher Elisha Dunn) |
Subjects
| Genre | Theses |
|---|
Bibliographic information
| Statement of responsibility | Alexander Benjamin Neuhausen. |
|---|---|
| Note | Submitted to the Department of Electrical Engineering. |
| Thesis | Ph.D. Stanford University 2012 |
| Location | electronic resource |
Access conditions
- Copyright
- © 2012 by Alexander Benjamin Neuhausen
- License
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
Also listed in
Loading usage metrics...