Symmetrical Ambipolar Transport in SnO Thin-Film Transistors Enabled by Dopant-Induced Preferential Crystal Orientation toward Complementary Logic

Herein, we present a thulium (Tm) doping strategy combined with hafnium oxide passivation annealing to enhance the preferable orientation crystallinity in SnO films toward balanced hole and electron transport. The optimized ambipolar Tm-doped SnO thin-film transistors (TFTs) exhibit hole and electron mobilities of 30.1 cm2/V·s and 11.8 cm2/V·s with a turn-on voltage about 0 V, respectively. Furthermore, we fabricate complementary thin-film logic circuits using these ambipolar SnO TFTs, including inverters and NAND and NOR gates. A record gain of 474.5 (V/V) is obtained for our ambipolar SnO inverter at a supply voltage of 6 V, which is the highest value reported among all ambipolar material systems due to the matched p- and n-type behaviors of the ambipolar SnO TFTs. By expanding the understanding of ambipolar inverter behavior, this work highlights the significant potential of ambipolar SnO TFTs for future high-performance complementary thin-film circuits.