InZnTiON Channel Layer for Highly Stable Thin-Film Transistors and Light-Emitting Transistors

In this study, we incorporated TiN as a carrier suppressor into an amorphous InZnO channel to achieve stable channels for thin-film transistors (TFTs) and light-emitting transistors (LETs). The low electronegativity and standard electrode potential of the Ti dopant led to a reduction in the number of oxygen vacancies in the InZnO channel. Moreover, the substitution of nitrogen into the oxygen sites of InZnO effectively decreased the excess electrons. As a result, the cosputtering of the TiN dopant resulted in a decrease in the carrier concentration of the InZnO channel, serving as an effective carrier suppressor. Due to the distinct structures of TiN and InZnO, the TiN-doped InZnO channel exhibited a completely amorphous structure and a featureless surface morphology. The presence of oxygen vacancies in the InZnO channel creates trap states for electrons and holes. Consequently, the TFT with the InZnTiON channel demonstrated an improved subthreshold swing and enhanced stability during the gate bias stress test. Furthermore, the threshold voltage shift (ΔV_th) changed from 3.29 to 0.86 V in the positive bias stress test and from −0.92 to −0.09 V in the negative bias stress test. Additionally, we employed an InZnTiON channel in LETs as a substitute for organic semiconductors. The reduction in the number of oxygen vacancies effectively prevented exciton quenching caused by hole traps within the vacancies. Consequently, appropriate TiN doping in the InZnO channel enhanced the intensity of the LET devices.