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November 22-23, 2018 | Paris, France
Journal of Materials Science and Nanotechnology | Volume: 2
Materials Physics and Materials Science
International Conference on
Highly sensitive and selective gas sensor utilising tips pentacene based organic thin film transistor
Amjad Al Shawi
Bangor University, UK
Organic sensing technology has been widely investigated
in the last few years. The low fabrication cost, high
sensitivity, short response and recovery time allowed
this type of sensors to dominate the research activities in
academia and industry. In this work, solution processed
organic thin film transistors (OTFTs) based on 6,13-bis
(triisopropylsilylethynyl) (TIPS) pentacene were fabricated
and characterized using the bottom-gate, top-contact (B-
G, T-C) configuration. After preparing clean glass substrate,
a 50nm aluminium was thermally evaporated as the gate
electrode. The insulating layer was spin coated (2000 rpm)
from a cross-linked polymethyl methacrylate (cPMMA) 5%
anisole solution by using [1,6-bis(trichlorosilyl) hexane (C6-
Si) (10µ/1ml) as a cross-linking agent to produce 330nm
layer thick. Tips-pentacene semiconductor (2% toluene
solution) was drop coasted on the cPMMA layer as the
active layer. Finally, gold electrodes of 50nm thickness were
thermally evaporated on the TIPS-pentacene active layer
to provide the drain and source. After exposing the OTFTs
to different concentrations of ethanol vapour, the current-
voltage characteristics of the OTFT sensor and the response
to different concentrations of ethanol (from 1ppm to 8ppm)
were investigated. The output characteristics (VDS = 0 – (-60)
V) with different gate voltages (VGS= 0 – (-50) V) and different
ethanol concentration were investigated. It was found that
the drain source current in the saturation region decreases
rapidly when the OTFT was exposed to ethanol vapour at
room temperature (~25 Co). Furthermore, the transfer
characteristics with different ethanol concentrations showed
a clear shift in the threshold voltage, which increased (from
-2V to -18 V) with increasing the ethanol concentration.
Therefore, the source drain current in the TIPS pentacene based
OTFTs can be considered as a significant parameter to monitor
chemicalspeciesanditcanbeusedasasensorforchemicalgases.
Speaker Biography
Amjad Al Shawi is a PhD student at the school of electronic engineering, Bangor
University, UK. He is in his third year of the PhD in the field of organic transistors and
organic memory devices. He completed his and study in physics from Basra
University, Iraq. He worked as a researcher in the Polymer Research Centre at Basra
University.
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