A Self-Selector and Self-Rectifying Charge-Trap-Based Resistive Switching Device Using In₂Se₃ Thin Films

Indium selenide (In2Se3) thin films have been observed to be a promising candidate for resistive switching-based neuromorphic computing applications owing to their various ferroelectric phases. It has been observed that the defects play a major role in the phase formation and performance of In2Se3-based devices. In the present work, a forming-free, nonlinear, and self-rectifying charge-trap-based resistive switching device is demonstrated in planar and vertical geometry using the layered phases of In2Se3 layers, namely, α-In2Se3 and β-In2Se3. The formation energy of intrinsic point defect calculations carried out using density functional theory (DFT) reveals that the deep trap levels play a major role in charge-trap-assisted resistive switching, exhibiting a flat band potential, which depends on the applied voltage range with an on/off ratio of ∼102 for α-In2Se3 in the planar configuration. Further, α-In2Se3 is utilized for the thickness-dependent planar resistive switching, where bilayer α-In2Se3 shows a high rectification ratio of ∼102. On the other hand, bilayer α-In2Se3 is exploited for out-of-plane switching characteristics and it is observed that bilayer α-In2Se3 behaves as a self-selector device with a selectivity of ∼105. Thus, the present study enlightens the charge-trap-assisted resistive switching in In2Se3 layers due to the presence of intrinsic point defects. Also, the bilayer α-In2Se3 exhibits a planar self-rectifying and vertical self-selector memory function for future application in crossbar array-based neuromorphic computing devices offering lower sneak path currents and power consumption.