Date on Master's Thesis/Doctoral Dissertation

8-2017

Document Type

Master's Thesis

Degree Name

M.S.

Department

Chemistry

Degree Program

Chemistry, MS

Committee Chair

Zamborini, Francis P.

Committee Co-Chair (if applicable)

Grapperhaus, Craig A.

Committee Member

Grapperhaus, Craig A.

Committee Member

Baldwin, Richard P.

Committee Member

O'Toole, Martin

Author's Keywords

nanoelectronics; single ag nanoparticle chain; 1D nanochains; 1D nanowires; controlled resistance

Abstract

This study mainly focuses on the fabrication of single one dimensional (1D) NP chains across the 5-micron gap of Au two electrode devices (TED). This has been achieved by electrochemical deposition of Ag onto the two electrodes, soaking the TED in 0.1 M Cetyltrimethyl ammonium bromide for 2-3 hours, and then close monitoring of the current as a function of time while a voltage across the two Ag coated Au electrodes in air. One dimensional Ag nanoparticle chain formation occurred by oxidation of Ag to Ag+ at the positive electrode followed by movement of Ag+ ions to the negative electrode and deposition by reduction of Ag+. Chain formation could be detected by current spike in a current time plot at a specific voltage. High voltage of 3-5 V and the appearance of multiple spikes led to several chains across the gap with uncontrolled current. We fabricated single 1D nano chains by applying a voltage of 1 V across the Ag deposited TEDs for 1000 seconds. If no current spikes appeared, we went to 2 V for 1000 s, and so on until the first appearance at a current spike. After the first spike appeared, we then stopped the voltage and went to 1 V for a certain amount of time until the current reached the desired level. This led to single nanoparticle chains with controlled resistance values ranging from 0.1 to 10 s of kilo ohms. The chain morphology chained dramatically depending on the resistance of the chain and the Ag deposition method. Chains formed from the electrodeposited Ag nanoneedles displayed chains of Ag nanoparticles well-aligned single file at high resistance and more continuous rods/wire at low resistance. Chains formed from electrodeposited Ag nanoneedles displayed chains of Ag nanoparticles well-aligned single file at high resistance and more continuous rods/wire at low resistance. Chains formed from electrodeposited Ag NP films display a cone shape with wide base at positive electrode and more narrow chain at the negative electrode, especially for higher resistance wires.

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