Preparation and characterization of SnO films via reactive sputtering for ambipolar thin-film transistor applications

Abstract SnO films are prepared by reactive magnetron sputtering under various O 2 partial pressures along with post-annealing in air. The results indicate that the O 2 partial pressure during reactive sputtering process not only influences the composition of the SnO film but also its texture. For the SnO film deposited under 10% O 2 partial pressure, its direct bandgap increases from 2.49 to 2.64 eV with elevating the post-annealing temperature from 250 °C to 400 °C. The above SnO-based channel thin-film transistors (TFTs) exhibit a typical ambipolar feature after post-annealing at ≥250 °C in air. For the TFTs annealed at 300 °C for 30 min, the extracted hole and electron field-effect mobility is 1.48 cm 2 V −1 s −1 and 0.21 cm 2 V −1 s −1 , respectively. The performance of both p- and n-type TFTs could be further improved by optimizing fabrication process and post-annealing conditions because of a trade-off between hole and electron mobility.