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 SnO₂ via Sn²⁺ to Sn⁴⁺ 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.