Charge transport in novel materials
There are more than 1000 compounds with particularly interesting 2D structures. Most of these atomically-thin crystals are air-sensitive and therefore should be handled in a glove box environment. Black phosphorus is one of them and we have demonstrated ultra-long stability of transistors made of BP by developing an encapsulation process under inert gas environments. We have also demonstrated ohmic contacts to these BP transistors made of 2D materials such as graphene and BN/Co. Similarly, by utilizing graphene as ohmic contacts to monolayer MoS2, we realized electric-field confined quantum point contact in high mobility MoS2. We also discovered a metal-to-semiconductor transition in PtSe2 as its thickness gets less than 2.5 nm.
The technical knowledge we have developed in the fabrication of mesoscopic 2D material devices over the years will be very instrumental while investigating the strong correlation physics of moire flat bands.
Related Publications:
1. Logic-in-memory based on an atomically thin semiconductor, G. M. Marega, Y. Zhao, A. Avsar, Z. Wang, M. Tripathi, A. Radenovic and A. Kis, Nature, 587 72-77 (2020).
2. Thickness-Modulated Metal-to-Semiconductor Transformation in a Transition Metal Dichalcogenide, A. Ciarrocchi, A. Avsar, D. Ovchinnikov and A. Kis, Nature Communications, 9, 919 (2018). Highlighted at Nature Review Materials.
3. Reconfigurable Diodes Based on Vertical WSe2 Transistors with van Der Waals Bonded Contacts, A. Avsar, K. Marinov, E. G. Marin, K. Watanabe, T. Taniguchi, G. Iannaccone, G. Fiori and A. Kis, Advanced Materials, 1707200 (2018).
4. Resolving the Spin Splitting In the Conduction Band of monolayer MoS2, K. Marinov, A. Avsar, K. Watanabe, T. Taniguchi, and A. Kis, Nature Communications, 8,1938 (2017).
5. van der Waals bonded Co/h-BN contacts to ultra-thin Black Phosphorus devices, A. Avsar, J.Y.Tan, X. Luo, K. H. Khoo, Y. Yeo, K. Watanabe, T. Taniguchi, S. Y. Quek and B. Özyilmaz, Nano Letters, 17, 5361-5367 (2017).
6. Air-stable transport in graphene-contacted, fully encapsulated ultrathin black phosphorus field-effect transistors, A. Avsar, I. J. Vera-Marun, J. Y. Tan, K. Watanabe, T. Taniguchi, A. H. Castro Neto, and B. Özyilmaz, ACS Nano, 9, 4138-4145 (2015).
7. Quantum transport detected by strong proximity interaction at a Graphene-WS2 Van der Waals interface, E. C. T. O’Farrell, A. Avsar, J. Y. Tan, G. Eda and B. Özyilmaz, Nano Letters, 15, 5682-5688 (2015).
