Nanoscale Devices Based on Two-dimensional and Ferroelectric Materials

Ferroelectrics have a spontaneous electric polarization that can be reversed by the application of an external electric field, while two-dimensional (2D) materials are crystalline solids consisting of one or few layer(s) of atoms. In ferroelectric/2D heterostructures, the ferroelectric materials can provide programmable and non-volatile doping in the 2D materials, while the atomically thin body in 2D materials enables strong electrostatic control over the channel by the polarized ferroelectric metal oxides. A wide range of nanoscale devices have been developed based on ferroelectric/2D hetero structures including high-performance nonvolatile memories, steep slope transistors, programmable junctions, charge and pressure sensors, and photodiodes [1]–[4]. In recent years, van der Waals (vdW) ferroelectrics emerged, which are 2D materials with intrinsic ferroelectric order. These vdW materials can retain ferroelectricity down to 1 unit-cell thickness, have tunable bandgap, and can be grown or transferred on any substrate [5]–[7], thus enabling a new series of optoelectronic and electromechanical devices. In this talk, we will discuss our recent work in developing reconfigurable, multifunction and analog devices based on ferroelectric/2D heterostructures and vdW ferroelectric materials [8]–[14].