Liquid-Metal-Printed Ultrathin Oxides for Atomically Smooth 2D Material Heterostructures

Abstract

Two-dimensional (2D) semiconductors are promising channel materials for continued downscaling of complementary metal-oxide-semiconductor (CMOS) logic circuits. However, their full potential continues to be limited by a lack of scalable high-k dielectrics that can achieve atomically smooth interfaces, small equivalent oxide thicknesses (EOTs), excellent gate control, and low leakage currents. Here, large-area liquid-metal-printed ultrathin Ga2O3 dielectrics for 2D electronics and optoelectronics are reported. The atomically smooth Ga2O3/WS2 interfaces enabled by the conformal nature of liquid metal printing are directly visualized. Atomic layer deposition compatibility with high-k Ga2O3/HfO2 top-gate dielectric stacks on a chemical-vapor-deposition-grown monolayer WS2 is demonstrated, achieving EOTs of ∼1 nm and subthreshold swings down to 84.9 mV/dec. Gate leakage currents are well within requirements for ultrascaled low-power logic circuits. These results show that liquid-metal-printed oxides can bridge a crucial gap in dielectric integration of 2D materials for next-generation nanoelectronics.

Dielectrics for Two-Dimensional Transition-Metal Dichalcogenide Applications

“…Another intriguing prospect is liquid metal synthesized ultrathin oxides, , of which several have been demonstrated including high-κ dielectrics such as Ga 2 O 3 , , HfO 2 , Al 2 O 3 , and Gd 2 O 3 . Liquid metal synthesized oxide was demonstrated as a gate dielectric in 2D TMDs . Here, an ultrathin Ga 2 O 3 layer was directly printed on 2D WS 2 from liquid gallium in a low-temperature process and led to atomically smooth interfaces (Figure k,l).…”

“…Another intriguing prospect is liquid metal synthesized ultrathin oxides, 70,71 as a gate dielectric in 2D TMDs. 129 Here, an ultrathin Ga 2 O 3 layer was directly printed on 2D WS 2 from liquid gallium in a low-temperature process and led to atomically smooth interfaces (Figure 3k,l). Subsequent ALD growth of HfO 2 led to a gate dielectric stack that achieved 1 nm EOT with excellent subthreshold swings and gate leakage currents.…”

“…Copyright 2022 Springer Nature. (k, l) Reprinted with permission from ref . Copyright 2023 American Chemical Society.…”

Probing charge traps at the 2D semiconductor/dielectric interface

“…Many studies use the SS method for D it extraction as a quick and easy method for interface characterization in FET devices. 174–179 The transfer characteristics of the device shown in Fig. 6j are shown in Fig.…”

Construction of a label-free electrochemical immunosensor based on a Co9S8/Co3C@C dual-heterojunction for the detection of diethylstilbestrol

“…Through the contact, electrons are transferred until the work functions are equal. 34,35 Chemical doping, 36 nanostructure engineering, 37 and construction of hybrids 38 are all viable strategies for fulfilling the fabrication of heterostructures. It consequently seems extremely positive to combine alternative construction approaches to create heterostructures.…”