Physical Property Evaluation of ZnO Thin Film Fabricated by Low-Temperature Process for Flexible Transparent TFT

Abstract

The usual silicon-based display back planes require fairly high process temperature and thus the development of a low temperature process is needed on flexible plastic substrates. A new type of flexible organic light emitting transistor (OLET) had been proposed and investigated in the previous work. By using ultraviolet/ozone (UV/O3) assisted thermal treatments on wet processed zinc oxide field effect transistor (ZnO-FET), through low-process temperature, ZnO-FETs were fabricated which succeeded to achieve target drain current value and mobility. In this study, physical property evaluation of ZnO was conducted in term of their crystallinity, the increase composition of ZnO formed inside the thin film and the decrease of the carbon impurities originated from aqueous solution of the ZnO itself. The X-ray diffraction (XRD) evaluation showed UV/03 assisted thermal treatment has no obvious effect towards crystallinity of ZnO in the range of low process temperature. Moreover, through X-ray photoelectron spectroscopy (XPS) evaluation and Fourier transform infrared (FT-IR) spectroscopy evaluation, more carbon impurities disappeared from the ZnO thin film and the increase of composition amount of ZnO, when the thin film was subjected to UV/O3 assisted thermal treatment. Therefore, UV/O3 assisted thermal treatment contributed in carbon impurities elimination and accelerate ZnO formation in ZnO thin film, which led to the improvement in the electrical property of ZnO-FET in the low-process temperature.

Low-temperature sol–gel oxide TFT with a fluoropolymer dielectric to enhance the effective mobility at low operation voltage

“…olution-processed sol-gel semiconducting amorphous metal oxide thin-film transistors (sol-gel oxide TFTs) are considered as a potential candidate next-generation optoelectronic device owing to their performance being superior to those of organic and amorphous silicon-based TFTs. Their unique properties, including high field effect mobility, low production cost, and good transparency to visible light enable us to extend their application in several fields such as those involving transparent devices, 1) flexible electronics, 2) and sensors. 3) However, despite all the merits of metal-oxide TFTs, a high operation voltage (i.e., higher than 10 V) may cause energy waste.…”