Ultraviolet/ozone-assisted thermal treatment of low-temperature-processed printable ZnO field-effect transistors for flexible displays

Wet processed ZnO films for semiconductor layers bring positive impact on fabrication of field-effect transistors (FETs) in terms of their low process temperature and manufacturing cost reduction. In our work, with the aim of fabricating organic light-emitting transistors (OLETs) using transparent ZnO FETs as the driver transistors, we have fabricated a wet processed ZnO film as a semiconductor layer, and investigated the effects of ultraviolet/ozone (UV/O-3)-assisted thermal treatments on ZnO FET characteristics. The results on the carrier mobility and thermal treatment temperature of ZnO films showed that the carrier mobility is almost proportional to treatment temperature, and the UV/O-3-assisted thermal treatment lowers the thermal treatment temperature. Moreover, devices subjected to UV/O-3-assisted thermal treatments showed excellent electrical characteristics compare with devices without the treatments. These results show that the UV/O-3-assisted thermal treatment is expected to facilitate OLET fabrication on flexible plastic films. (C) 2014 The Japan Society of Applied Physics