2D Materials Engineering for Electron Devices

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The discovery of the graphene field effect transistor over a decade ago precipitated a renaissance in 2D materials: 2-dimensional sheets of tightly bound atoms stacked together. The layered materials include insulators, semiconductors, semimetals and metals. The long-term goal of my research program is to understand and exploit the unique properties of 2D materials for electron devices. Over the past 5 years my research group has: developed graphene oxide acoustic devices now being commercialized by start-up ORA Graphene Audio, achieved record pH sensing precision with graphene transistors, achieved a world record for quantum Hall effect in low mobility material, and we were among the first to observe 2D charge transport in black phosphorus. ******Building on our expertise with graphene and black phosphorus, my research program has three main themes: new 2D materials, new 2D transistor fabrication techniques, and new 2D transistor structures. In the first theme, we will characterize the bandstructure and charge transport characteristics of SnSe, a polar analogue of black phosphorus with record thermoelectric figure of merit. We will also exfoliate ultra-thin layers of Sb, a heavier pnictogen than black phosphorus, where there is a competition between spin-orbit coupling and quantum confinement leading to a predicted semimetal to semiconductor transition as the atomic layer limit is approached. In parallel, we will develop a flip-chip method that will allow us to fabricate transistors with environmentally sensitive 2D materials such as black phosphorus in a completely inert environment, minimizing the deleterious effects of oxidation. Lastly, we will develop new transistor structures in black phosphorus. This includes quantum point contacts to understand spin polarized current flow in black phosphorus, and dual-gate transistors that apply the Stark effect for bandgap tuning during transistor operation.******Highly qualified personnel (HQP) will be trained using state of the art research infrastructure including semiconductor device characterization tools. A glove box with optical microscopy, atomic force microscopy, and exfoliation tools enables the fabrication of 2D material transistors. HQP have access to shared use facilities such as the Laboratoire de Microfabrication at École Polytechnique with electron beam lithography and Raman spectroscopy tools. My group is a regular user of the National High Magnetic Field Laboratory (NHMFL) in Tallahassee for access to the world's highest static magnetic fields. We have active ongoing collaborations with researchers around the world who provide complementary expertise in areas such as molecular beam epitaxy, scanning tunelling microscopy, transmission electron microscopy, and angle resolved photoemission spectroscopy. Graduated HQP are employed as engineers at established firms, are leading start-ups of their own, or are teachers.