Simultaneous Enhancement of Electrical Performance and Negative Bias Illumination Stability for Low-Temperature Solution-Processed SnO2 Thin-Film Transistors by Fluorine Incorporation

In this article, fluorine (F)-doped SnO
₂
(FTO) thin-film transistors (TFTs) are fabricated by the solution process with a low process temperature (300 °C). The FTO film characteristic, TFT electrical performance, and stability under the negative bias illumination stress (NBIS) are improved by F doping. The enhancement in electrical performance and stability is because F can substitute oxygen atom in the lattice and oxygen vacancies in FTO system. The FTO TFT with 3 mol.% F doping ratio shows superior electrical performance with saturation mobility (μ) of 14.48 cm
²
/V·s, a threshold voltage (V
_TH
) of 1.01 V, a subthreshold swing (SS) of 0.19 V/decade, and an ON/OFF current ratio (I
_on
/I
_off
) of 9.32 × 10
⁷
. Furthermore, the 3 mol.% FTO TFT shows only -0.8 V V
_TH
shift under NBIS. The total density of states (DOSs) for the FTO TFT is extracted in order to further verify the stability improvement based on the temperature-dependence field-effect measurement. The results indicate that the simple solution-processed FTO-TFT is promising for application in electronics.