Abstract
High-current level ZnO thin-film transistors (TFTs) on transparent substrates
are demonstrated using low-temperature RF sputtering. Oxygen passivation induced
fill of oxygen vacancies within the sputtered n-type ZnO thin films on glass
substrates is investigated to manipulate the performance of top-gate ZnO TFTs.
The surface oxygen passivation effectively enlarges grain size of the ZnO
on glass substrates from 7 nm to 20 nm and increases the oxygen composition
ratio from 30% to 35%, which essentially yields a TFT with its significantly
increase of drain-source current and $I_{\rm
on}/I _{\rm off}$ ratio, as compared with a typical ZnO based
TFT. The optimum duration of oxygen passivation in this study yields a device
with a drain-source current level 0.87 mA under a bias condition $V _{\rm GS} =5~{\hbox{V}}$ and $V_{\rm DS}
=15~{\hbox{V}}$, $I_{\rm
on} /I_{\rm off}$ ratio ${\hbox{1.4}}\times {\hbox{10}} ^{6}$. We further
demonstrate high-performance top-gate ZnO TFTs by applying similar low-temperature
process on a flexible polymer substrate. The device shows an $I _{\rm DS}$ 26 $\mu{\hbox{A}}$ under a bias condition $V _{\rm GS} =15~{\hbox{V}}$ and $V_{\rm DS}
=25~{\hbox{V}}$ with gate size $W/L=600~\mu {\hbox{m}}/300~\mu {\hbox{m}}$.
The average optical transmission of the entire flexible TFT structure in the
visible spectrum range is about 82% while the transmission at 550 nm is 88%.
© 2009 IEEE
PDF Article
More Like This
Cited By
You do not have subscription access to this journal. Cited by links are available to subscribers only. You may subscribe either as an Optica member, or as an authorized user of your institution.
Contact your librarian or system administrator
or
Login to access Optica Member Subscription