Structural, chemical, optical, and electrical evolution of solution-processed SnO 2 films and their applications in thin-film transistors

We demonstrate the formation of n-type transparent SnO 2 thin films by solution process. The influences of annealing temperature (200 °C–700 °C) on the microstructural, chemical, optical, and electrical performances of the SnO 2 thin films are systematically investigated by a variety of characterization techniques. The results reveal that the solution-processed SnO 2 thin film undergoes the elimination of organic and Cl-related residues along with the conversion of Sn(OH) 4 to form crystalline SnO 2 , with the rising annealing temperature. This also leads to the improvement of the Hall mobility (from 0.3 to 13.7 cm 2 V −1 s −1 ). Furthermore, the optimized SnO 2 thin-film transistor annealed at 450 °C exhibits the highest saturation mobility of 0.511 cm 2 V −1 s −1 , on/off current ratio of 2.3 × 10 4 , on voltage of −23.6 V, and subthreshold swing of 5.06.