Comparative Study of Antimony Doping Effects on the Performance of Solution-Processed ZIO and ZTO Field-Effect Transistors

ZnO-based oxide films are emerging as high-performance semiconductors for field-effect transistors (FETs) in optoelectronics. Carrier mobility and stability in these FETs are improved by introducing indium (In) and gallium (Ga) cations, respectively. However, the strong trade-off between the mobility and stability, which come from In or Ga incorporation, still limits the widespread use of metal oxide FETs in ultrahigh pixel density and device area-independent flat panel applications. We demonstrated that the incorporation of antimony (Sb) cations in amorphous zinc indium oxide (ZIO) simultaneously enhanced the field-effect mobility (μ_FET) and electrical stability of the resulting Sb-doped ZIO FETs. The rationale for the unexpected synergic effect was related to the unique electron configuration of Sb⁵⁺ ([Kr]4d¹⁰5s⁰5p⁰). However, the benefit of Sb doping was not observed in the zinc tin oxide (ZTO) system. All the Sb-doped ZTO FETs suffered from a reduction in μ_FET and a deterioration of gate bias stress stability with an increase in Sb loading. This can be attributed to the formation of heterogeneous defects due to Sb-induced phase separation and the creation of Sb³⁺ induced acceptor-like trap states.