UV-Ozone-Assisted Solution-Processed High-k ZrO₂for MoS₂ Field-Effect Transistors

MoS2 field-effect transistors (FETs) based on high- <tex-math notation="LaTeX">k </tex-math> gate insulators (such as ZrO2, HfO2, and Al2O3) have been explored. However, the preparation of high- <tex-math notation="LaTeX">k </tex-math> dielectrics typically requires high-vacuum equipment, leading to high cost. In this report, high- <tex-math notation="LaTeX">k </tex-math> ZrO2 dielectrics were prepared by a facile ultraviolet-ozone (UVO)-assisted solution process. The ZrO2 thin films annealed at different temperatures were investigated by optical transmission spectroscopy, atomic-force microscopy, and impedance analyzer. Subsequently, MoS2 FETs based on ZrO2 dielectrics annealed at various temperatures were prepared and the electrical performances of the FETs were investigated. The MoS2 FET based on ZrO2 dielectric annealed at 300 °C demonstrates a high field-effect mobility of 89.6 cm2/Vs, an ON-current of <tex-math notation="LaTeX">10^-5 </tex-math> A/ <tex-math notation="LaTeX">μ m </tex-math> , an ON/OFF current ratio of <tex-math notation="LaTeX">10^8 </tex-math> , and a subthreshold swing (SS) of 95.2 mV/dec. To explore the prospective logic applications of MoS2/ZrO2 FETs, a resistor-loaded inverter was fabricated and a high gain of 32 was achieved. This work demonstrates the feasibility of solution-processed high- <tex-math notation="LaTeX">k </tex-math> dielectrics for 2-D semiconductor FETs, providing a new route to realize cost-effective and low-power 2-D semiconductor electronics and circuits.