Selective Polarity Control of Metal Oxide Semiconductors for Complementary Logic Gates

Realizing tunable charge carrier polarity is essential for programmable complementary logic circuits. While two‐dimensional (2D) semiconductors have demonstrated polarity controllability through Schottky barrier modulation or contact engineering, their high interfacial sensitivity limits scalability and integration. Here, we present a robust polarity‐conversion strategy for tin oxide (SnO) semiconductors based on electrolyte‐gated transistors (EGTs). In situ electrochemical doping enables the conversion of p‐type SnO to n‐type SnO 2 via Sn 2+ to Sn 4+ oxidation. Both p‐ and n‐type EGTs exhibit outstanding electrical characteristics, including low‐voltage operation, high ON/OFF current ratios, sharp switching behavior, and reliable long‐term stability. Furthermore, we demonstrate the monolithic integration of complementary logic gates, including inverter, NAND, and NOR gates, through spatially selective electrochemical doping of a single SnO layer. Overall, this work provides a scalable and versatile pathway toward oxide‐based programmable complementary circuits.