Layered Materials: Crystal Growth For Future Device Structures

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• Prof. Luigi Colombo, (University of Texas at Dallas, USA)
• Friday 11 January 2019, 16:00-17:00
• Cambridge Graphene Centre Seminar Room.

If you have a question about this talk, please contact Dr Anna Ott.

The isolation of graphene has given rise to the revitalization of an old full set of materials, layered materials (LMs), with unique electrical, chemical and physical properties. Some of the materials under investigation in addition to graphene are hexagonal boron nitride (h-BN), semiconducting, metallic, and superconducting, transition metal dichalcogenides (TMD) with a general chemical formula, MX2 where M is for example equal to Mo, W, Ta, Nb, Zr, Ti, and X = S, Se and Te, and others. While graphene is a material with many exceptional properties and h-BN is an excellent insulator, TMDs provide what neither graphene nor h-BN can, bandgap engineering that, in principle, can be used to create new devices that cannot be fabricated with h-BN and graphene alone. There is hope that LMs can be integrated to fabricate numerous device types for many applications ranging from inkjet-printed circuits, photonic applications, flexible electronics, and high performance electronics. However, in order to fully realize the benefits of these materials, the community will have to work together to define the device structures, device integration schemes, and materials growth processes and requirements, together with production equipment. A number of deposition techniques have been used to prepare large area graphene, such as growth on SiC through the evaporation of Si at high temperatures, precipitation of carbon from metals, and chemical vapor deposition on Cu. Direct growth of good quality graphene on dielectrics/semiconductors other than SiC with reasonable properties has only been reported recently on Ge. The preparation of large area h-BN is also in great demand and processes are being developed to achieve this on both metals and dielectrics. TMDs present altogether different opportunities and difficulties in the preparation of low defect density large area single crystals. Vapor transport, chemical vapor deposition (CVD), and molecular beam epitaxy (MBE) are being developed to produce these materials for initial studies of materials physics and device fabrication. A number of devices structures are currently under evaluation to take advantage of the basic properties of graphene, h-BN and TMDs. Some of the devices are based on tunneling phenomena while others are based on excitonic phenomena. I will present state-of-the-art results on graphene, h-BN, and TMDs, and their prospects for device applications.

This talk is part of the Graphene CDT Advanced Technology Lectures series.

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• Cambridge Graphene Centre Seminar Room
• Graphene CDT Advanced Technology Lectures

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