Double-Gate Modulated Corbino TFTs

Short-channel Corbino thin-film transistors (TFTs) exhibit infinite output resistance beyond pinchoff when the outer-ring electrode is biased as the drain but suffer from low drain currents. It is shown here that the employment of a thin (<;25 nm) amorphous oxide semiconductor and a double-gate (DG) structure (with a top-gate electrically tied to a bottom-gate) increases the drain currents of the Corbino TFTs biased in the outer-drain condition by over two times through bulk-accumulation (BA), without compromising their infinite output resistance beyond pinchoff or bias, temperate, and light stability. By experiment and through 3-D TCAD simulations, evidence of BA under DG modulation and the origin of the infinite output resistance beyond pinchoff in Corbino TFTs are also revealed in this letter.