Electric field-modulated data storage in bilayer InSe

Recently, due to the unexpectedly high carrier mobility and strongly suppressed recombination of electron–hole pairs, exfoliated atomically thin InSe has exhibited potential applications in nanoscaled electronic devices. In this study, via first-principle calculations, we have systematically investigated the crystal and electronic structures of bilayer InSe with different stacking configurations. Interestingly, the five possible stacking configurations of bilayer InSe can be categorized into two groups: Group-S with a shorter vdW interlayer distance and smaller band gap and Group-L with a longer vdW interlayer distance and larger band gap. It is highlighted that the indirect band gap bilayer InSe can be transformed into its metallic type. We have unraveled that the electronic origin of the band gap transition is derived from the electric field-induced near free-electron gas. Furthermore, a prototype data storage device based on the bilayer InSe has been proposed; this study will shed light on the design and application of bilayer InSe as well as two-dimensional material-based electronic devices in the future.