Low-voltage solution-processed P-type Mg-doped CuI thin film transistors with NAND logic function

Abstract

Low-voltage electric-double-layer (EDL) p-channel Mg-doped CuI thin-film-transistors (TFTs) have been fabricated on glass substrates at low temperatures. Electrical properties of the solution-processed CuI TFTs with different Mg doping concentrations were investigated. It is observed that compared to undoped CuI TFTs and Mg0.1Cu0.9Ix TFTs, Mg0.05Cu0.95Ix TFTs exhibit an excellent current on/off ratio of 1.1 × 105, a steep subthreshold swing of 21.78 mV/dec, a higher saturation field-effect mobility of 0.95 cm2 V−1 s−1, and the threshold voltage of 1.81 V. The high specific capacitance of 4.7 μF/cm2 is obtained in solution-processed chitosan dielectrics; when it was used as the gate dielectric instead of traditional SiO2, the operating voltage of TFTs can be reduced to 2.5 V. It is noteworthy that the NAND logic function has been realized on the dual in-plane-gate structure of such Mg0.05Cu0.95Ix-based TFTs. Finally, the effects of laser (λ = 638 nm) and negative bias stress (NBS) were observed on Mg0.05Cu0.95Ix TFTs. The transfer curves of the TFT drifted positively as the power of the laser progressively increased; the OFF-state current gradually increased as the NBS time became longer. This paper provides an effective way to improve the performance of p-channel CuI TFTs and indicates that Mg0.05Cu0.95Ix as a promising p-type material for next-generation high-performance low-power-consumption logic circuit applications.