Xiong, Hui
(2006)
Fabrication and Characterization of Nano Probes for Scanning Electrochemical Microscopy.
Master's Thesis, University of Pittsburgh.
(Unpublished)
Abstract
Selectively etched optical fibers were used as a template for fabrication of ultramicroelectrodes (UME), which are suitable for use as a probe in scanning electrochemical microscopy (SECM). Multistep index optical fibers with high-GeO2-doped core and two cladding layers were chemically etched to a sharp point (10 nm in diameter) in NH4F/HF buffer solutions. The etched fibers had a defined geometry and the etching process was highly reproducible. After etching, a layer of gold was sputtered on the fibers. The Au-coated fibers were then insulated by electrophoretic paint. The size and shape of the electrodes were determined by steady-state cyclic voltammetry and SECM. The SECM tip current-distance (approach) curves over conductive and insulating substrates agreed with the theoretical curves obtained by numerical simulations, which proves a conical electrode geometry. The base radius and height of the conical electrodes determined by SECM were in the range of 0.255-1.0 and 0.3-1.2 ƒÝm, respectively.In order to fabricate electrodes within 200 nm in radius using selectively etched optical fiber as the template, we tried several approaches: (1) Using focused ion beam (FIB) milling we could cut the gold-coated tip at desired size with nanometer precision. However, after electrophoretic paint deposition on FIB modified fibers, the apparent size of the electrode increased against our expectation from FIB, which indicated that gold exposed not only at the tip but also on the side-wall. (2) Insulating gold-coated probes by sputtering silicon oxide has been investigated.
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| Item Type: |
University of Pittsburgh ETD
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| Status: |
Unpublished |
| Creators/Authors: |
|
| ETD Committee: |
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| Date: |
28 September 2006 |
| Date Type: |
Completion |
| Defense Date: |
3 December 2004 |
| Approval Date: |
28 September 2006 |
| Submission Date: |
16 May 2006 |
| Access Restriction: |
No restriction; Release the ETD for access worldwide immediately. |
| Institution: |
University of Pittsburgh |
| Schools and Programs: |
Dietrich School of Arts and Sciences > Chemistry |
| Degree: |
MS - Master of Science |
| Thesis Type: |
Master's Thesis |
| Refereed: |
Yes |
| Uncontrolled Keywords: |
Nano Probes; Scanning Electrochemical Microscopy |
| Other ID: |
http://etd.library.pitt.edu/ETD/available/etd-05162006-111214/, etd-05162006-111214 |
| Date Deposited: |
10 Nov 2011 19:44 |
| Last Modified: |
15 Nov 2016 13:43 |
| URI: |
http://d-scholarship.pitt.edu/id/eprint/7891 |
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