Abstract
The aim of the present dissertation is to improve the understanding and methodology of temperature-dependent tunnel conduction through individual molecules by single-electron transport spectroscopy. New advances in electrochemistry present individual molecular diodes as a realistic option for the implementation on molecular circuits thanks to their high current rectification ratios. Therefore, a major requisite in this field is to understand and control the conduction behaviors for a large variety of conditions. This work focuses on the electric conduction through ferrocene-based molecules as a function of temperatures within a wide range of bias and gate voltages by means of three-terminal electromigrated-broken single-electron transistors (SETs). The results show that the temperature dependence of the current (from 80 to 260 K) depends strongly on the bias and gate voltages, with areas in where the current increases exponentially with temperature (at the Coulomb blockade regimes), and others where the increase of the temperature makes the current only to vary slightly (at resonance) or to decrease monotonically (at the charge degeneracy points). These different observed behaviors of the tunneling current with increasing temperatures can be well explained by a formal single-level coherent tunneling model where the temperature dependence relies on the thermal broadening of the Fermi distributions of the electrons in the leads. The model portraits the molecule as a localized electrostatic level capacitively coupled to the transistor leads, and the electrical conduction through the junction as coherent sequential tunneling.
Notes
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Graduation Date
2016
Semester
Spring
Advisor
Del Barco, Enrique
Degree
Doctor of Philosophy (Ph.D.)
College
College of Sciences
Department
Physics
Degree Program
Physics
Format
application/pdf
Identifier
CFE0006171
URL
http://purl.fcla.edu/fcla/etd/CFE0006171
Language
English
Release Date
May 2016
Length of Campus-only Access
None
Access Status
Doctoral Dissertation (Open Access)
STARS Citation
Rodriguez Garrigues, Alvar, "Electrostatic control over temperature-dependent tunneling across single-molecule junctions" (2016). Electronic Theses and Dissertations. 4927.
https://stars.library.ucf.edu/etd/4927