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Abstract

High κ dielectrics, such as HfO₂, Al2O₃ and so on, are widely used to preserve the properties of two-dimensional (2D) semiconductors in electronic devices. However, fabricating these materials on the wafer scale and integrating them with 2D semiconductors is challenging because their synthesis typically requires mechanical exfoliation or not enough high κ or expensive. Here, we show that a high-κ (Ga, Cu) co-doped ZnO dielectric can be created on wafer scale via pulsed laser deposition. Ga_0.5Cu₂Zn_97.5O film with large κ=56 and Al₂O₃ film with large band gap are selected to fabricate bilayer composite dielectric films. Ga_0.5Cu₂Zn_97.5O/Al₂O₃ gate dielectric stack combine the advantages of both Ga_0.5Cu₂Zn_97.5O and Al₂O₃ films. We demonstrate that gate stack is more favorable for transistors than single dielectric, featuring for a large κ (45.63) and a lower leakage current. Tin disulfide (SnS₂) field-effect transistors supported by Al₂O₃/Ga_0.5Cu₂Zn_97.5O dielectric stack to meet the requirement of energy band structure of gate dielectrics, which shows mobility 2.455 cm²/Vs. And we apply trap-assisted tunneling model to fit the gate current vs gate electric field. Tunneling currents have been calculated as a function of gate voltage for different structures.