Areas of Research

Our group studies new materials including two-dimensional (2D) materials and emerging ferroelectric materials and investigates novel electronic/photonic devices based on these materials. More specifically, we synthesize ferroelectric metal oxides and 2D materials, investigate ferroelectric tunneling junctions (FTJs) and memory devices based on ferroelectric materials, explore logic transistors, radio frequency devices, photodetectors, and plasmonic devices based on 2D materials, and 2D/ferroelectric hybrid stacks. These new material platforms and novel devices will have broad applications from data centers to sensor networks and flexible electronics.

2D Materials

2D materials are a class of nanomaterials defined as being merely a few atoms thick. These materials have strong in-plane covalence bond, but very weak inter-plane van der Waals (vdW) bonds. As a result, these materials can be exfoliated into atomically thin layers.  There are more than one hundred different 2D materials, including graphene, transition metal dichalcogenides, black phosphorus, boron nitride, Mxene, and monochalcogenides. These materials have many unique electrical, optical, and mechanical properties. Our group investigate the synthesis of 2D materials and explore the nanoscale devices based on 2D materials, including Esaki diodes, resonant tunneling diodes (RTDs), logic tranistors,  RF devices, ferroelectric memories, photodetectors, and plasmonic devices.

Ferroelectric Materials

A ferroelectric dielectric is a polar dielectric in which the polarization can be switched between two or more stable states by the application of an electric field. Ferroelectric complex perovskites, such as lead zirconate titanate (PZT), strontium bismuth tantalate (SBT), and lead magnesium niobate-lead titanate (PMN-PT) have been widely used in ferroelectric devices. In the last few years, doped metal oxides, including hafnium oxide (HfO2) and zirconium oxide (ZrO2), were found to have ferroelectric phase. Ferroelectric HfO2 has the advantages of a high coercive field, excellent scalability, and good compatibility with CMOS processing. Our group investigate the formation of these new ferroelectric materials on 2D materials, and explore energy efficient devices using these stacks. In addition, vdW ferroelectric materials have emerged as a new class of ferroelectric materials. As compared to traditional ferroelectric materials, vdW ferroelectric materials are free of dangling bonds and offer merits including bandgap tunability, mechanical flexibility, and high carrier mobility. Our group investigates novel nanoscale electronic and photonic devices based on vdW ferroelectric materials.