Event Title

Effect of Smoothening Electrodes on Revealing Finer Molecular Level Information in Charge Transport

Date

1-4-2017 12:00 AM

Major

Materials Engineering

Department

Materials Science and Engineering

College

College of Engineering

Project Advisor

Martin Thuo

Project Advisor's Department

Materials Science and Engineering

Description

In molecular electronics, molecules are the building blocks of electrical circuits. Within this area, self-assembled monolayers (SAMs) continue to gain interest. Self-assembled monolayers arise from spontaneous organization of molecules into ordered and well-defined layers on a surface. We seek to understand how charge tunnels through organic monolayers and the role of the monolayer in this process. To study charge transport, a eutectic indium gallium (EGaIn) top electrode passes current onto a substrate (bottom electrode) through the SAM. Different preparation methods of the liquid metal top electrode led to variances in observed current density and to discrepancies in inferences related to SAM structure. By polishing the electrode with an acetic acid solution, we developed a universal method to address the disparities. The polished EGaIn electrode in combination with an ultra-flat substrate (Au Ti-TS ) led to significant improvement in measurement sensitivity to molecular interface properties. Heat maps and Gaussian distributions generated from this improved platform showed sharp and symmetric distributions. This confirms that observed results were sensitive to interface properties of SAMs. With the development of this method, we gain better fundamental molecular level information on SAMs. This has the potential to contribute to the use of SAMs in electronic-chemical sensor fabrication.

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Apr 1st, 12:00 AM

Effect of Smoothening Electrodes on Revealing Finer Molecular Level Information in Charge Transport

In molecular electronics, molecules are the building blocks of electrical circuits. Within this area, self-assembled monolayers (SAMs) continue to gain interest. Self-assembled monolayers arise from spontaneous organization of molecules into ordered and well-defined layers on a surface. We seek to understand how charge tunnels through organic monolayers and the role of the monolayer in this process. To study charge transport, a eutectic indium gallium (EGaIn) top electrode passes current onto a substrate (bottom electrode) through the SAM. Different preparation methods of the liquid metal top electrode led to variances in observed current density and to discrepancies in inferences related to SAM structure. By polishing the electrode with an acetic acid solution, we developed a universal method to address the disparities. The polished EGaIn electrode in combination with an ultra-flat substrate (Au Ti-TS ) led to significant improvement in measurement sensitivity to molecular interface properties. Heat maps and Gaussian distributions generated from this improved platform showed sharp and symmetric distributions. This confirms that observed results were sensitive to interface properties of SAMs. With the development of this method, we gain better fundamental molecular level information on SAMs. This has the potential to contribute to the use of SAMs in electronic-chemical sensor fabrication.