Liquid-Metal-Printed Ultrathin Oxides for Atomically Smooth 2D Material Heterostructures
Yiyu Zhang, Dasari Venkatakrishnarao, Michel Bosman, Wei Fu, Sarthak Das, Fabio Bussolotti, Rainer Lee, Siew Lang Teo, Ding Huang, Ivan Verzhbitskiy, Zhuojun Jiang, Zhuoling Jiang, Jianwei Chai, Shi Wun Tong, Zi‐En Ooi, Calvin Pei Yu Wong, Yee Sin Ang, Kuan Eng Johnson Goh, Chit Siong Lau
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 Ga 2 O 3 dielectrics for 2D electronics and optoelectronics are reported. The atomically smooth Ga 2 O 3 /WS 2 interfaces enabled by the conformal nature of liquid metal printing are directly visualized. Atomic layer deposition compatibility with high- k Ga 2 O 3 /HfO 2 top-gate dielectric stacks on a chemical-vapor-deposition-grown monolayer WS 2 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.