Theoretical assessment of multi-doping strategies in amorphous indium oxide for synergistically enhancing carrier mobility and bias stability

Abstract

Amorphous indium oxide (a-In₂O₃) materials treated with various dopants are leading candidates for advanced display technologies. As the channel layer in thin-film transistors (TFTs), the material must simultaneously exhibit high carrier mobility and robust bias stability. However, current experimental results predominantly reveal an empirical trade-off between these two parameters, which poses significant challenges for rational material design. In this work, we carried out a density functional theory (DFT) study, assisted by ab initio molecular dynamics (AIMD) simulations, to theoretically assess multi-doping strategies in the a-In₂O₃ system. The effect of foreign metal dopants, including zinc (Zn), cadmium (Cd), gallium (Ga), tin (Sn), praseodymium (Pr), and tungsten (W), on the mobility and bias stability of the host material was evaluated by the extracted effective electron mass and metal–oxygen bond length, respectively. Our results show that, compared to the conventional quaternary indium–gallium–zinc–oxide (IGZO) system, the pentanary indium–tin–gallium–zinc–oxide (ITGZO) design could concurrently enhance the carrier mobility and bias stability of the film. The simulation results are in agreement with the reported experimental findings. Such a theoretical assessment approach may pave the pathway to source material design of novel metal oxide semiconductor materials.