Impact of glycerol on zinc oxide based thin film transistors with indium molybdenum oxide electrodes

Thin-film transistors (TFT) were fabricated at a room-temperature (RT) with zinc oxide (ZnO) channel and indium molybdenum oxide (IMO) electrodes. To isolate the gate oxide and gate electrode influence on the device performance, common gate configuration on a commercial substrate with thermal Si02 (100 nm) was selected. A threshold voltage (VTh) of 10 V and IonIIoff ratio of 1 x 10-5 were obtained. Once the reference data was taken transistors were exposed to glycerol. Temporary changes in device characteristics were observed due to the influence of glycerol, a low conductivity medium. To exclude the possibility of sugar alcohol being the main conductor, measurement on dummy transistor electrode was performed retaining the distance between probes. The TFT device under test revealed ten times higher drain current but also a change in threshold voltage and leakage current. Transistors under glycerol influence were always open with the positive gate bias.