Thesis (MScEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: During this research the possibility of using carbon nanostructures in sensors
were investigated. Graphene and carbon nanotubes (CNTs) are the nano-
structures that were used in the developed sensors. Graphene is a single
atomic layer of carbon and a carbon nanotube (CNT) is a rolled up sheet of
graphene that forms a tube. The unique structure and incredible properties
of both these materials make them ideal to be used in sensory applications. A
graphene sensor was developed and experiments were performed to determine
whether graphene is a viable candidate to be used in a wide range of sensory
applications. The graphene sensor operated successfully as a humidity sensor
and this led to the discovery that humidity can be used to control the bandgap
in graphene. The absorption of CO2 in graphene was successfully measured
using surface acoustic waves. As a result, any gas that graphene absorbs can be
detected using this method. The use of graphene in three liquid applications
was tested. The graphene showed no potential to be used as a pH sensor
or as a
ow sensor. An experiment was undertaken to determine whether
graphene can increase the e ciency of a water electrolysis process, but it
was established that the graphene does not make a signi cant di erence. A
CNT gas sensor that identi es a gas based on its ionization characteristics
was studied and designed. Due to the insu cient height of the grown CNTs,
it was decided to focus on the creation of a model of the sensor that can be
used to design it optimally. The results of the experiments con rmed that
carbon nanostructures such as graphene and CNTs have potential to be used
in future sensing applications. / AFRIKAANSE OPSOMMING: Hierdie navorsing ondersoek die moontlikheid om koolstof-nanostrukture in
sensor-apparate te gebruik. Grafeen en koolstof-nanobuisies (KNB) is die
nanostrukture wat in die ontwikkelde sensors gebruik is. Grafeen is 'n
enkel atomiese koolsto
agie en KNBs is 'n opgerolde grafeenlagie wat 'n
buisie vorm. Die unieke struktuur en ongeloo
ike eienskappe van beide
hierdie materiale, maak hulle uiters geskik om in sensor-toepassings gebruik
te word. 'n Grafeensensor is ontwikkel en eksperimente is uitgevoer om
te bepaal of grafeen 'n goeie kanidaat is om in 'n wye verskeidenheid van
toepassings gebruik te word. Die grafeensensor is suksesvol aangewend as
'n humiditeitsensor en dit het gelei tot die uitvindsel dat humiditeit gebruik
kan word om die energiegaping in grafeen te varieer. Die absorpsie van CO2
in grafeen is suksesvol gemeet deur oppervlak akoestiese golwe te gebruik.
Gevolglik kan enige gas wat grafeen absorbeer op hierdie manier gemeet word.
Die gebruik van grafeen is in drie vloeistof-toepassings getoets. Die grafeen
het geen potensiaal getoon om as 'n pH-sensor of as 'n vloei-sensor aangewend
te word nie. 'n Eksperiment is ook uitgevoer om te toets of grafeen die
e ektiwiteit van 'n water-elektroliese proses kan verhoog, maar die resultate
het gewys dat dit nie 'n wesenlike verskil maak nie. 'n KNB-gassensor, wat
'n gas identi seer uit die ioniseerings eienskappe van die gas, is bestudeer en
ontwikkel. Die lengte van die KNBs wat gegroei is, was onvoldoende en daar
is gefokus op die ontwerp van 'n model van die sensor wat gebruik kan word
om dit optimaal te ontwerp. Die resultate van die eksperimente het bevestig
dat koolstof-nanostrukture soos grafeen en KNB baie potentiaal het om in
toekomstige sensor-toepassings gebruik te word.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/5389 |
| Date | 12 1900 |
| Creators | Kritzinger, Pieter Christo |
| Contributors | Perold, W. J., University of Stellenbosch. Faculty of Engineering. Dept. of Electrical and Electronic Engineering. |
| Publisher | Stellenbosch : University of Stellenbosch |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | Unknown |
| Type | Thesis |
| Format | 115 p. : ill. |
| Rights | University of Stellenbosch |
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