Summary: | 碩士 === 大同大學 === 化學工程學系(所) === 96 === The main aim of this thesis studies on the characteristics of flexible
thin-film transistor (TFT) fabricated with pentacene as a semiconductor layer,
poly(ethylene terephthalate) (PET) as a plastic substrate, polyamide (PA) and
poly(methyl methacrylate) (PMMA) acted as polymeric gate dielectric. We
have chosen 1-octadecanethiol (1-ODT) and octadecyltrichlorosilane (OTS)
used as treated agent for gate electrode to change the surface morphology of
gate electrode in order to improve the orientation of the pentacene deposited
on the polymer dielectric and to improvement device characteristics.
The capacitance is 1.88 nF/cm2 of PA, 1.94 nF/cm2 of PA/PMMA and
0.99 nF/cm2 of PA/PMMA dual layer through the measurement on the
architecture of Metal-Insulator-Semiconductor device at a frequency of 100
kHz. Part I, we have chosen PA acted as a polymeric gate dielectric. The
mobility and on/off current ratio of the pentacene TFT are 0.36 cm2/Vs and
8.05 × 102, respectively. Further, the mobility and on/off current ratio of TFT
with gate electrode treated with 1-ODT are 1.04 cm2/Vs and 1.40 × 103,
respectively. The mobility and on/off current ratio of TFT for capping the
surface of gate electrode with OTS are 1.33 cm2/Vs and 2.04 × 105,
respectively. Existence of a single crystal phase with more intensity in theXRD pattern can be obtained the better performance of device. Atom Force
Microscope (AFM) images showed that the surface of pentacene was more
flatness and larger grain size, which can reduce the grain boundaries and the
trap states, to improve the mobility.
Part II, we have chosen PA/PMMA dual layer acted as polymeric gate
dielectric. The mobility and on/off current ratio are 0.56 cm2/Vs and, 1.25 ×
106, respectively. It is found that the leakage current reduced significantly tobe 5 pA such that the on/off current ratio increased to about 106, which is
three orders of magnitude larger than that of device with PA gate dielectric.
However, the improvement on the characteristics of TFT with 1-ODT or
OTS treated gate electrode is unobvious. Part III, we have chosen PMMA/PA
dual layer acted as polymeric gate dielectric. The mobility and on/off current
ratio are only 0.30 cm2/Vs and 5.63× 103, respectively, but the I-V curves of
the device exhibit the ideal characteristics.
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