Physical origin of broadened transition voltage in 2D TMD FETs

Determine the physical origin of the broadened off-to-on transition and the associated transition-voltage behavior in two-dimensional transition metal dichalcogenide field-effect transistors.

Background

The paper introduces transition voltage as a metric for quantifying the gate-voltage window required to switch emerging two-dimensional TMD FETs from the off-state to the deep on-state. Devices can exhibit competitive subthreshold swing and on-current while requiring a substantially larger transition window than silicon MOSFETs, indicating that conventional performance metrics do not fully capture their switching behavior.

The unresolved physical origin may involve process-induced trap charges, distributed interface and border traps, gate-dependent Schottky-barrier modulation, near-band-edge trap states at the source contact, or other process-dependent interface effects that weaken gate control during the transition region. Identifying the dominant mechanism would help guide gate-stack and process optimization.

References

Its physical origin in 2D TMD FETs remains unclear but possible mechanisms include process-induced trap charges, distributed interface and border traps, gate-dependent Schottky barrier modulation with near-band-edge trap states at the source contact and other process-dependent interface effects that weaken gate control in the transition region [2].

— Process-Technology Co-optimization for 2D-FETs  (2609.00722 - Yang et al., 1 Sep 2026) in Section II.A, “Motivation for Defining Transition Voltage”