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Electrochemically-Grown Single Nanowire Array for Highly Sensitive and Selective Chemical Detection

Hu, Yushi (2011) Electrochemically-Grown Single Nanowire Array for Highly Sensitive and Selective Chemical Detection. Doctoral Dissertation, University of Pittsburgh. (Unpublished)

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One dimensional nanostructures (nanowires) have emerged as important building blocks for micro/nano devices, such as chemical and biomolecular sensors, photovoltaic devices, nonvolatile memories, and nano power generators. In this work, the fabrication and characterization of single metal, conducting polymer and metal oxide nanowires will be discussed. These single nanowires were synthesized site-specifically inside Polymethyl methacrylate (PMMA) channels defined by electron beam lithography (EBL) via electrochemical deposition. The dimensions of these nanowires were predefined by optical lithography and EBL, and the widths were from 100 nm to 50 nm and the lengths were from 3 to 7 microns. A gate-assisted electrochemical deposition method that was able to effectively improve the nanowire growth will be discussed. The successful integration of four different single nanowires on a single chip will also be demonstrated.The applications of these single nanowires will be presented. A highly sensitive hydrogen sensor with fast response (<20 s) and extremely low detection limit (2 ppm) was achieved using single Palladium (Pd) nanowire. The structure of the Pd nanowire was found to be closely related to the growth condition, and different sensing mechanisms were discovered for different nanowire structures.An electronic nose was built on a single chip using a nanowire array consisting of four different single nanowires, including Pd, Polypyrrole (PPy), Polyaniline (PANI), and ZnO nanowires. The sensing performances of this electronic nose for four different target gases, including carbon monoxide (CO), hydrogen (H2), nitrogen dioxide (NO2), and methanol (CH3OH), were studied in detail. Principal Component Analysis (PCA) was employed to analyze the sensing signals and each target gas was clearly identified. A blind test was conducted to verify the performance of this e-nose.


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Item Type: University of Pittsburgh ETD
Status: Unpublished
CreatorsEmailPitt UsernameORCID
ETD Committee:
TitleMemberEmail AddressPitt UsernameORCID
Committee ChairYun, Minheeyunmh@engr.pitt.eduMIY16
Committee MemberFalk, JoelFalk@engr.pitt.eduFALK
Committee MemberChen, Kevinkchen@engr.pitt.eduPEC9
Committee MemberCho, Sung Kwonskc@engr.pitt.eduSKCHO
Committee MemberStanchina, Williamwstanchina@engr.pitt.eduWES25
Date: 19 September 2011
Date Type: Completion
Defense Date: 7 June 2011
Approval Date: 19 September 2011
Submission Date: 9 June 2011
Access Restriction: 5 year -- Restrict access to University of Pittsburgh for a period of 5 years.
Institution: University of Pittsburgh
Schools and Programs: Swanson School of Engineering > Electrical Engineering
Degree: PhD - Doctor of Philosophy
Thesis Type: Doctoral Dissertation
Refereed: Yes
Uncontrolled Keywords: chemical sensor; Electrochemical deposition; electronic nose; nanowire
Other ID:, etd-06092011-161118
Date Deposited: 10 Nov 2011 19:46
Last Modified: 15 Nov 2016 13:44


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