The potassium-assisted p-type characteristics of tin oxide in solution-processed high-performance metal oxide thin-film transistors

Developing high-performance p-type metal-oxide semiconductors comparable to n-type ones has opened a new window for the realization of transparent, flexible, and low-power integrated circuits in large-area electronics. Herein, the fabrication of solution-processed p-type metal-oxide thin-film transistors (TFTs) with excellent device performance at low temperatures using a novel material is reported. Potassium (K) content is introduced into the tin oxide precursor solution to stabilize the tin (II) oxide (SnO) phase rather than the tin (IV) oxide (SnO${}_2$) phase during thin-film formation. The optimized K-doped SnO (K-SnO) TFTs exhibit outstanding electrical performance, with a maximum Hall mobility of 51 cm${}^2$ V${}^{-1}$ s${}^{-1}$ and a field-effect hole mobility of 2.3 cmcm${}^2$ V${}^{-1}$ s${}^{-1}$. The achievement of the solution-processed K-SnO TFTs not only provides a significant step toward the development of complementary metal-oxide semiconductor circuits, but also represents a feasible approach for low-cost flexible p-type metal-oxide electronics. (© 2021 Wiley‐VCH GmbH)