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Northwestern Photonics Club's Student Speaker Series

Modified: April 15, 2016

Graduate students and postdocs are invited to attend Northwestern Photonics Club's Student Speaker Series --A New 2D Material, Synthesis and Characterization of Borophene by Andrew Mannix from Department of Materials Science and Engineering on April 20th at 12pm. 

Click here to RSVP.

Abstract: Two-dimensional (2D) carbon (i.e., graphene) revolutionized the fields of materials science and condensed matter physics through its superlative mechanical, thermal, and electronic properties. Subsequently, many 2D materials have been isolated from bulk solids consisting of weakly bound sheets (e.g., MoS2, hBN, and black phosphorus). However, this approach has fundamentally limited the study of 2D materials to those with bulk layered structures. The growth of entirely synthetic 2D materials—those without bulk analogues—dramatically expands our capability to develop materials with new and interesting properties.

Like carbon, boron is among the most structurally diverse and chemically complex elements. For instance, bulk boron is reported to have 16 distinct allotropes with strong, complex, and highly coordinated chemical bonding. At the nanoscale, boron clusters adopt carbon-like structures, including small planar molecules and cage-like fullerenes. Numerous theoretical studies have predicted that boron may form two-dimensional (2D) sheets (i.e., borophene), which could surpass carbon nanostructures in strength and conductivity. Furthermore, borophene could provide the basis for an entire family of boron nanostructures (analogous to carbon nanotubes and fullerenes). However, until recently it was not known if borophene could be experimentally realized.  

In this talk, I will discuss our recent synthesis of borophene in ultra-high vacuum, on silver substrates [Science 350, 1513–1516 (2015)]. Using atomic-scale scanning tunneling microscopy, we find two borophene phases, both exhibiting significant anisotropy and commons structural motifs. We employ multiple orthogonal characterization techniques to verify that these sheets are atomically thin and structurally distinct from the substrates and compare our results with first-principles structure calculations. Significantly, borophene appears to be metallic, unlike semiconducting bulk boron, and may prove useful in applications that harness its significant electronic and mechanical anisotropy.

Bio: Andrew Mannix is a 4th year PhD candidate in Materials Science and Engineering at Northwestern University, supported by a NSF Graduate Research Fellowship. He earned his BS in Materials Science and Engineering at the University of Illinois at Urbana-Champaign in 2012. Mannix’s past research includes the growth of graphene and graphene nanostructures on various substrates, the growth of 2D silicon nanosheets, and the functionalization of metal surfaces with biologically relevant amino acids. His research interests include the growth, characterization, and chemical modification of post-graphene two-dimensional materials, with a particular interested in ultra-high vacuum growth and scanning tunneling microscopy.

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