The present work investigated the electrical characteristics of Corbino structure p-type tin monoxide (SnO) thin-film transistors (TFTs) and demonstrated a high-performance complementary logic inverter composed of Corbino p-type SnO and n-type indium-gallium-zinc oxide (IGZO) TFTs. Experimental data showed that the Corbino p-type SnO TFT exhibited an almost infinite output resistance beyond pinch-off in the outer drain condition. The observed phenomenon was mainly attributed to the scaling down of the effective channel width in proportion to the effective channel length. By using the very high output resistance of the Corbino structure TFTs, we fabricated the high-gain complementary logic inverter composed of Corbino p-type SnO and n-type IGZO TFTs. The Corbino TFT-based complementary logic inverter showed a voltage gain of 92.4 at a supplied voltage of 10 V, which was significantly higher than that of 18.7 obtained from the complementary logic inverter composed of the conventional rectangular shaped TFTs.

We investigated the effect of simultaneous mechanical and electrical stress on the electrical characteristics of flexible indium-gallium-zinc oxide (IGZO) thin-film transistors (TFTs). The IGZO TFTs exhibited a threshold voltage shift (∆V_TH) under an application of positive-bias-stress (PBS), with a turnaround behavior from the positive ∆V_TH to the negative ∆V_TH with an increase in the PBS application time, whether a mechanical stress is applied or not. However, the magnitudes of PBS-induced ∆V_TH in both the positive and negative directions exhibited significantly larger values when a flexible IGZO TFT was under mechanical-bending stress than when it was at the flat state. The observed phenomena were possibly attributed to the mechanical stress-induced interface trap generation and the enhanced hydrogen diffusion from atomic layer deposition-grown Al₂O₃ to IGZO under mechanical-bending stress during PBS. The subgap density of states was extracted before and after an application of PBS under both mechanical stress conditions. The obtained results in this study provided potent evidence supporting the mechanism suggested to explain the PBS-induced larger ∆V_THs in both directions under mechanical-bending stress.

The promotive effect of a pre-bias condition on the recovery speed of a field-effect transistor-type gas sensor, which has a horizontal control gate (CG) and floating gate (FG), is investigated in this letter. To verify the pre-bias effect in the recovery phase after the detection of H ₂ S gas, a type of reducing gas, a 200-nm-thick layer of SnOx is deposited on top of the interdigitated CG and FG as a sensing material. A pulse measurement method is proposed to improve the recovery speed of the sensor for H ₂ S gas sensing by applying a negative pre-bias condition to the CG before the read operation of the sensor. This method greatly accelerates the recovery and reduces the recovery time by 74% with a pre-bias of -3 V at 180°C. The mechanism is explained in terms of energy band theory. The pre-biasing method used with our gas sensor is beneficial for the continuous monitoring and for the rapid detection of various gases.