Efficient Oxygen‐Vacancy Suppression and Electrical Stabilization of Solution‐Processed In2O3:Q (Q = S, Se) Thin‐Film Transistor with Chalcogen Alloying

Abstract Transparent oxide semiconductors are successfully implemented as thin‐film transistors (TFTs) for large‐area display applications with superior electrical performance in comparison with that of conventional amorphous silicon. However, further development of high‐performance oxide semiconductors is hindered by the trade‐off between mobility and stability. Mixed metal composition containing heavy metal cations shows high‐mobility/low‐stability and light metal cations exhibits low‐mobility/high‐stability. A novel material design strategy for realizing a high‐performance oxide semiconductor for TFTs through partial substitution of Se or S for O in In 2 O 3 is reported. In contrast to the conventional small‐sized Ga substitution for suppressing oxygen vacancies, the replacement of O by Se or S results in lattice stabilization and oxygen‐vacancy suppression, consequently stabilizing Se‐ or S‐incorporated In 2 O 3 TFTs. In 2 O 3 :Se TFTs exhibit an average field‐effect mobility of 6.1 cm 2 V −1 s −1 , ON/OFF current ratio ( I on / I off ) of 10 8 , and excellent operational stability with threshold voltage shift values of < 0.10 V at a positive and negative bias stress for 10 000 s. Furthermore, the seven‐stage ring oscillator circuit operating at a supply bias of 20 V exhibits an oscillation frequency of > 805 kHz and a corresponding propagation delay of <90 ns per stage.