Affiliate Faculty (Associate Professor – ENG/ME)
Nanomechanical Properties of a New Class of 2D Atomically Thin Materials
Our research focuses on the nanomechanical properties of a new class of 2D atomically thin materials, such as graphene (single atomic layers of graphite). We are most interested in their remarkable mechanical properties such as high strength, extreme flexibility, and unprecedented barrier properties. We fabricate and characterize nanomechanical devices, our favorite of which is a graphene sealed microcavity formed from a single atomic sheet of graphene suspended over a micron sized etched wells on a silicon wafer. The suspended graphene forms an “atomic drum” which can be vibrated at MHz frequencies using lasers. In addition, we can apply pressure differences and stretch these drum skins. This unique geometry has allowed us to experimentally measure a number of physical properties of 2D materials such as their elastic constants, molecular transport and barrier properties, and adhesive interactions. These atomically thin membranes act as barriers for gases and liquids and represent the thinnest membrane possible (one layer of atoms) with the smallest potential pore sizes attainable (single atomic vacancies), and unprecedented mechanical stability. The applications that we are primarily interested in are semipermeable membranes for gas or liquid separations and nanomechanical sensors.
“Adhesion, Stiffness, and Instability in Atomically Thin MoS2 Bubbles” D. Lloyd, X. Liu, N. Boddeti, L. Cantley, R. Long, M. L. Dunn, J. S. Bunch, Nano Letters, 17, 5329-5334 (2017)
“Band Gap Engineering with Ultralarge Biaxial Strains in Suspended Monolayer MoS2” D. Lloyd, X. Liu, J. Christopher, L. Cantley, A. Wadehra, B. Kim, A.K. Swan, B.B. Goldberg, and J.S. Bunch, Nano Letters, 16, 5836-5841 (2016)
“Molecular valves for controlling gas phase transport made from discrete angstrom-sized pores in graphene” L. Wang, L. W. Drahushuk, L. Cantley, S. P. Koenig, X. Liu, J. Pellegrino, M.S. Strano, and J. S. Bunch, Nature Nanotechnology, 10, 785-790 (2015)
“Selective Molecular Sieving through Porous Graphene”S. P. Koenig, L. Wang, J. Pellegrino, and J. S. Bunch, Nature Nanotechnology, 7, 728-732 (2012).
“Ultrastrong Adhesion of Graphene Membranes” S. P. Koenig, N. G. Boddeti, M. L. Dunn, J. S. Bunch, Nature Nanotechnology 6, 543-546 (2011)
For a full list of publications, please see the attached CV