THESIS
2017
xiii, 106 pages : illustrations (some color) ; 30 cm
Abstract
Graphene has attracted a large amount of attention in sensing applications due to its
remarkable properties such as large surface area, high carrier mobility and sensitivity which
make it ideal for the field. Graphene-based field effect transistor (GFET) in particular is an
extremely sensitive platform for detecting various surface modulations and interactions.
However, GFETs still have a number of challenges that hinder its full potential such as
selectivity and reliability. This thesis presents two main works with GFET sensors. The first
work involves fabricating a GFET device with two-dimensional paper networks (2DPN) as a
component. The paper network serves as both a gate dielectric and an easy-to-fabricate vessel
for containing the solution with the analyte species which a...[
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Graphene has attracted a large amount of attention in sensing applications due to its
remarkable properties such as large surface area, high carrier mobility and sensitivity which
make it ideal for the field. Graphene-based field effect transistor (GFET) in particular is an
extremely sensitive platform for detecting various surface modulations and interactions.
However, GFETs still have a number of challenges that hinder its full potential such as
selectivity and reliability. This thesis presents two main works with GFET sensors. The first
work involves fabricating a GFET device with two-dimensional paper networks (2DPN) as a
component. The paper network serves as both a gate dielectric and an easy-to-fabricate vessel
for containing the solution with the analyte species which are in this case DNA and glucose.
The choice of paper enables a simpler alternative approach to the construction of a GFET
device, which was shown to behave similarly to a solution-gated GFET with comparable
electron-hole mobilities and Dirac points, and was able to produce current changes correlated
with the analyte concentration. The second work involves the use of molecularly imprinted
polymers (MIP), which were electrochemically grown on the surface of graphene to grant the
GFET sensor high selectivity towards specific analyte molecules. The use of MIP allowed for
the construction of a highly selective sensor without compromising the high mobility of
pristine graphene. The polybithiophene-based MIP used in this work was electropolymerized
on the surface of a CVD graphene, which was then shown to maintain the properties of
graphene such as high carrier mobility as indicated by the I-V
g curves from its field-effect
transistor (FET) device. Sensing studies using histamine as a model analyte demonstrated that
the binding of the analyte with MIP induced current responses in the sensor where higher
electron mobility was observed which was largely attributed to the electron sharing of
histamine with the MIP during binding. The binding interaction of the MIP-analyte system
was noted to play a crucial role in the detection where electron sharing and coordination is
implicitly required to induce the current response.
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