Solution-processed zinc oxide (ZnO) thin-film transistors (TFTs) obtained via
hydrolysis/pyrolysis of an organic precursor present an excellent technique to
obtain high performance electronic devices with low manufacturing cost. In the
current work, we propose the use of an alternative deposition method, based on a
polymeric precursor route (known as Pechini), to obtain solution-processed ZnO
compact films as the active layer of TFTs. The elimination of the organic phase
and the formation of inorganic thin-films was carried out by thermal treatment
at different temperatures (ranging from 200°C to 500°C) and at
different times (from 5 min to 2 hours), being monitored by UV-vis and infrared
(IR) optical absorption spectroscopy. It was observed that, for temperatures
above 400°C and treatment times superior to 30 min, the organic phase
was completely eliminated, remaining only the inorganic (metal oxide) phase. The
optical bandgap of the resulting ZnO films, determined from UV-vis absorption,
is about 3.4 eV. The electrical characteristics (output and transfer curves) of
the obtained devices demonstrate the feasibility of Pecchini method to build
solution-processed metal oxide TFTs. The results for the electrical mobility of
the majority charge-carriers (electrons) and for the threshold voltage were 0.39
cm2.V-1.s-1 and 0.45 V, respectively.