  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 (EOT), excellent gate control, and low
leakage currents. Here, we report liquid metal printed ultrathin and scalable
Ga2O3 dielectric for 2D electronics and electro-optical devices. We directly
visualize the atomically smooth Ga2O3/WS2 interfaces enabled by the conformal
nature of liquid metal printing. We demonstrate atomic layer deposition
compatibility with high-k Ga2O3/HfO2 top-gate dielectric stacks on chemical
vapour deposition grown monolayer WS2, achieving EOTs of ~1 nm and subthreshold
swings down to 84.9 mV/dec. Gate leakage currents are well within requirements
for ultra-scaled low-power logic circuits. Our results show that liquid metal
printed oxides can bridge a crucial gap in scalable dielectric integration of
2D materials for next-generation nano-electronics.
