Improving Electrical Performances of -Type SnO Thin-Film Transistors Using Double-Gated Structure

p-type SnO thin-film transistors (TFTs) using a nominally symmetrical double-gated (DG) structure were studied in this letter. The top and bottom gates can be biased independently (single-gated mode) or jointly to switch the device (DG mode). For the latter operation, it is shown that ON current, subthreshold swing, and OFF-state current of the SnO TFT are all improved as compared with the operations when only one of the two gates is biased. As the device is operated under the DG mode, field-effect mobility of 6.54 cm²/V-s, high ON/OFF current ratio of > 10⁵, and subthreshold swing of 143 mV/decade are obtained. Moreover, the capability of the device in tuning its transfer characteristics under the single-gated operation with the bias applied to the opposite gate is also confirmed.