We proposed the fabrication of Li-Zn-Sn-O (LZTO) thin film transistors (TFTs) using a magnetron co-sputtering method. To analyze the effects of Li incorporation on the amorphous LZTO TFTs, Hall measurement and X-ray photoelectron spectroscopy were performed. It was found that the increased addition of Li to the ZTO system caused the suppression of carrier creation. At an optimized condition (similar to 12 at.% Li) for LZTO TFTs, we achieved a saturation mobility of similar to 10.4 cm(2)/V s, a subthreshold voltage of 0.25 V/decade, a threshold voltage (V-th) of 3.9 V, and an I-on/off ratio of 2x10(8). Furthermore, the optimized device exhibited much better photo-bias stability (Delta V-th=-3.3 V) than the reference ZTO device (Delta V-th=-10.8 V) under the negative bias illumination stress condition. (C) 2012 Elsevier B.V. All rights reserved.