Electrical characteristics of solution-processed InGaZnO thin film transistors depending on Ga concentration

We investigated the role of Ga in solution-processed InGaZnO thin film transistors (TFTs). The incorporation of Ga into a InZnO compound system results in a decrease in the carrier concentration of the films and an off-current of TFTs. This is a result of the Ga ions forming stronger chemical bonds with oxygen, as compared to the Zn and In ions, acting as a carrier suppressor. It was verified, using X-ray photoelectron spectroscopy (XPS), that the vacancy-related oxygen is peak was decreased when the Ga content increased. (C) 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim