High Hole Mobility Inorganic Halide Perovskite Field‐Effect Transistors with Enhanced Phase Stability and Interfacial Defect Tolerance

Abstract So far, it has been difficult to fabricate thin‐film field‐effect transistors (TFTs) based on inorganic halide perovskites (IHPs) due to their phase‐instability and uncontrollable trap density. Here, the bottom‐gate bottom‐contact structured p‐type TFTs are presented using the optimized IHP in the active layer. The stable cubic‐CsPbI 3 phase is successfully synthesized by doping bismuth iodide and reduced defect densities by adding potassium bromide. The IHP TFTs based on the tailored cubic‐CsPbI 3 show high hole mobility of ≈ 10 cm 2 V −1 s −1 , an on‐off current ratio of 10 3 , and a low subthreshold swing voltage of 0.43 V dec −1 . In addition, the operational stability of the fabricated device is demonstrated through the bias stress test. This study suggests that one of the key factors for fabricating an ideal p‐type IHP transistor is managing charge transport properties in the IHP layer through defect engineering.