Enhanced Electrical Performance and Negative Bias Illumination Stability of Solution-Processed InZnO Thin-Film Transistor by Boron Addition

In this paper, boron-doped indium–zinc–oxide (InZnO) thin-film transistors (BIZO TFTs) were fabricated by solution process. The electrical performance and stability under the negative bias illumination stress (NBIS) have been greatly improved by B doping. The BIZO TFT with 5 mol.% B doping ratio shows a superior electrical performance with a field-effect mobility of 10.15 cm2/ $\textsf {V}\,\cdot \, \textsf {s}$ , a threshold voltage of 3.29 V, a subthreshold swing of 0.35 V/decade, and an ON/OFF ratio of 108. Furthermore, the 5 mol.% BIZO TFT shows only a −1.59 V shift of the threshold voltage, compared with a large negative shift of −4.24 V for pure IZO TFTs. The enhancement of electrical performance and stability under NBIS is due to the reduction of oxygen vacancies, which are suppressed by B doping. The density of states is calculated to further validate the improved electrical performance and NBIS stability of BIZO TFTs.