A clean van der Waals interface between the high-k dielectric zirconium oxide and two-dimensional molybdenum disulfide

Abstract Two-dimensional transition metal dichalcogenide semiconductors possess ideal attributes for meeting industry scaling targets for transistor channel technology. However, the development of scaled field-effect transistors (FETs) requires industry-compatible gate dielectrics with low equivalent oxide thicknesses. Here we show that zirconium oxide (ZrO 2 )—an industry-compatible high-dielectric-constant ( k ) oxide—can form a clean interface with two-dimensional molybdenum disulfide (MoS 2 ). Photoelectron spectroscopy analysis shows that although silicon dioxide and hafnium oxide substrates introduce the doping of MoS 2 , ZrO 2 exhibits no measurable interactions with MoS 2 . Back-gated monolayer MoS 2 FETs using ZrO 2 as a dielectric exhibit stable and positive threshold voltages of 0.36 V, subthreshold swings of 75 mV dec −1 and ON currents of more than 400 µA. We also use ZrO 2 dielectrics to fabricate p-type tungsten diselenide FETs with ON-state currents of more than 200 µA µm −1 . Atomic-resolution imaging of ZrO 2 deposited on top of MoS 2 reveals a defect-free interface, which leads to top-gated FETs with an equivalent oxide thickness of 0.86 nm and subthreshold swing values of 80 mV dec −1 . The clean interface between ZrO 2 and monolayer MoS 2 allows the effective modulation of threshold voltage in top-gated FETs via gate metal work-function engineering.