Title: Synthesis and Properties of Atomic Layered Transition-Metal Dichalcogenides

Tuesday, May 6, 2014 - 3:30pm - 4:45pm
Regents 109
Joshua Robinson
Pennsylvania State University

The isolation of graphene constituted a new paradigm in next generation electronic technologies, and even though graphene is considered transformational, it is only the “tip of the iceberg”. Transition metal dichalcogenides (TMDs) could have an even greater impact on next generation technologies. Similar to graphene, TMDs are composed of vertically stacked, weakly interacting layers that are scalable down to sub-nanometer thicknesses. This makes them impressive material candidates for analog and digital electronics. Molybdenum disulfide (MoS2) is currently a leading TMD for scientific exploration, but there are a variety of other suitable, less explored, TMDs and TMD heterostructures that exhibit very attractive band gaps, charge carrier effective masses, and mobilities for electronic applications. Transition-metal dichalcogenides in the form of MeX2 (where Me = a transition metal such as Mo, W, Ti, Nb, etc. and X = S, Se, or Te) also exhibit extreme flexibility, possession of tunable band gaps, modest electron mobilities, and a wide variety of band-offsets.

The ability to grow high quality, large area TMDs is the first critical step in the realization of electronics requiring atomic layers with tailored electronic band alignments. In this talk I will lay out the fundamentals of two-dimensional materials and why they are attractive for science and technology, discuss the applications of TMDs and TMD heterostructures, and provide an overview of our research in the synthesis and characterization of WSe2, WTe2, and TMD/graphene van der Waals solids, and show that heterostructures could be key to advanced electronic applications.

REFRESHMENTS AT 3:20 PM IN REGENTS HALL 109

Host: Jim Freericks
Discussion Leader: Wes Mathews