Wide-range and area-selective threshold voltage tunability in ultrathin indium oxide transistors

The scaling of transistors with thinner channel thicknesses has led to a surge in research on two-dimensional (2D) and quasi-2D semiconductors. However, modulating the threshold voltage (V(T)) in ultrathin transistors is challenging, as traditional doping methods are not readily applicable. In this work, we introduce a optical-thermal method, combining ultraviolet (UV) illumination and oxygen annealing, to achieve broad-range V(T) tunability in ultrathin In(2)O(3). This method can achieve both positive and negative V(T) tuning and is reversible. The modulation of sheet carrier density, which corresponds to V(T) shift, is comparable to that obtained using other doping and capacitive charging techniques in other ultrathin transistors, including 2D semiconductors. With the controllability of V(T), we successfully demonstrate the realization of depletion-load inverter and multi-state logic devices, as well as wafer-scale V(T) modulation via an automated laser system, showcasing its potential for low-power circuit design and non-von Neumann computing applications.