Tuned band offset in homogenous TMDs via asymmetric ferroelectric semiconductor gates toward simultaneous rectification and memory

Abstract

Band alignment engineering is crucial and feasible to enrich the functionalities of van der Waals heterojunctions (vdWHs) for rectifying functions in next-generation information storage technologies. However, band alignment tunability is volatile as it needs a sustained external field to maintain the Femi level of single components, which hinders the implementation of nonvolatile functions. Here, the ferroelectric semiconducting nature of alpha-In2Se3 is utilized to design vdWHs based on two-dimensional transition metal dichalcogenides (TMDs)/alpha-In2Se3, where TMDs are used as the channel, and the ferroelectric semiconductor alpha-In2Se3 is assembled as an asymmetric gate. A density functional theory validates that the band offset in a homogeneous TMDs channel is tuned by coupling the effect of the semiconducting nature and asymmetric ferroelectric gate of alpha-In2Se3, which induces simultaneous rectifying and memory functions. This includes a programmable rectifying ratio of up to 104, ultra-large memory window (110 V), programming/erasing of 104, and good endurance. The tuned band offset from the asymmetric ferroelectric semiconductor gate is conceptualized as a guideline to realize a simultaneous rectifying and memory device with high programmability.