Janus Electronic Devices with Ultrathin High‑κ Gate Dielectric Directly Integrated on 1T′-MoTe2

Integrating high-quality dielectrics with two-dimensional (2D) transition metal chalcogenides (TMDCs) is crucial for high-performance electronics. However, the lack of dangling bonds on 2D material surfaces complicates direct dielectric deposition. We propose using atomic layer deposition (ALD) to integrate ultrathin high-κ dielectric directly on 1T′-MoTe2 surfaces, facilitating the creation of high-performance back-gated field-effect transistors (FETs). Exploiting 1T′-MoTe2’s natural oxidation in ambient conditions, we directly deposit dense and uniform HfO2 dielectric films below 5 nm, achieving an equivalent oxide thickness (EOT) of 0.97 nm. The resulting back-gate transistors, with a monolayer MoSSe on HfO2/1T′-MoTe2, show a current on/off ratio over 105 and operate at low voltages (