Ferroelectric α‐In₂Se₃ Wrapped‐Gate β‐Ga₂O₃ Field‐Effect Transistors for Dynamic Threshold Voltage Control

Indium selenide (α‐In 2 Se 3 ), which is a recently emerging ferroelectric semiconductor, can solve a major hindrance to applications of an ultra‐wide bandgap beta‐gallium oxide (β‐Ga 2 O 3 ) semiconductor. Here, ferroelectric α‐In 2 Se 3 wrapped‐gate β‐Ga 2 O 3 field‐effect transistors (FETs) for dynamic threshold voltage ( V TH ) control is demonstrated. The dry‐transferred α‐In 2 Se 3 layer is wrapped around β‐Ga 2 O 3 channel, which allows efficient electrostatic gate modulation. Thus, the ferroelectricity of α‐In 2 Se 3 and a thin native oxide interlayer formed at the interface between β‐Ga 2 O 3 and α‐In 2 Se 3 can provide effective V TH control. Applying a positive voltage pulse to the gate electrode induces positive V TH shift; hence, the device can be even changed from depletion to enhancement (E‐) mode. The E‐mode β‐Ga 2 O 3 FET exhibits steep‐subthreshold slope with a negligible hysteresis. The V TH of E‐mode can be further modulated by applying back‐gate bias, and electrical performance can be enhanced via dual‐gate operation. The approach demonstrates an energy efficient β‐Ga 2 O 3 ‐based switching device architecture integrated with ferroelectric van der Waals 2D materials.