Combining Freestanding Ferroelectric Perovskite Oxides with Two-Dimensional Semiconductors for High Performance...

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• High-performance two-dimensional (2D) devices require advanced gate dielectrics.
• Standard silicon dioxide (SiO2) dielectrics limit device performance due to Coulomb scattering.
• Hexagonal boron nitride (hBN) is a high-performance dielectric but integration challenges exist.

Purpose of the Study:

• To fabricate field-effect transistors (FETs) using single-layer molybdenum disulfide (MoS2) and barium titanate (BTO) as an ultrahigh-κ gate dielectric.
• To investigate the impact of BTO dielectric on device mobility and electrical characteristics.
• To explore the potential of BTO's ferroelectric properties for memory applications.

Main Methods:

• Fabrication of MoS2-based FETs with isolated thin BTO dielectric layers.
• Electrical characterization of device mobility and current-voltage (I-V) gate characteristics.
• Temperature-dependent measurements to study the ferroelectric-to-paraelectric transition of BTO.

Main Results:

• Devices exhibited significantly enhanced carrier mobility compared to SiO2-based transistors.
• Mobility values were comparable to those achieved with hexagonal boron nitride (hBN).
• Robust gate voltage hysteresis was observed due to BTO's ferroelectric polarization switching, which diminished above the transition temperature.

Conclusions:

• Thin, isolated BTO serves as an effective ultrahigh-κ gate dielectric for 2D materials like MoS2.
• The ferroelectric properties of BTO offer promising avenues for non-volatile memory storage applications.
• This work facilitates the integration of complex oxide materials with strongly correlated physics into 2D electronic devices.