Fully-printed flexible n-type tin oxide thin-film transistors and logic circuits

Abstract

In this study, we achieved fully-printed flexible n-type tin oxide (SnO₂) thin-film transistors (TFTs) and logic inverters. The SnO₂ transistors exhibit outstanding performance with high saturation mobility of 13.3 cm² V⁻¹ s⁻¹, small subthreshold swing (SS) of 130 mV dec⁻¹, large current on/off ratio (I_on/I_off) of >10⁵, low turn-on voltage (V_on) of −0.04 V, and enhancement-mode operations (threshold voltage, V_th = 0.14 V). Moreover, the devices exhibited excellent electrical stability under positive bias stress (PBTS, ΔV_th = 0.16 V) and negative bias stress (NBIS, ΔV_th = −0.18 V) after 10 000 s voltage bias tests. The thickness-dependent bandgap widening together with TFT performance in SnO₂ thin films were also studied, illustrating that the nanometer-thin channel thickness played an important role in determining the switching performance of SnO₂ TFTs. Furthermore, the fully-printed SnO₂ TFTs exhibited robust mechanical flexibility with the minimum bending radius of 0.5 cm, promising for constructing advanced low-cost electronic devices and circuits.