Materials Growth and Characterization

Large area micrograph of an array of single layer graphene transistorsOur research on graphene synthesis primarily focuses on solving the problems associated with the large scale production and fabrication of electronic devices. Until recently, the fabrication of such devices was performed on exfoliated or transferred graphene, methods that are appropriate for single devices but are not facile or scalable. Our goal is to reduce these problems by synthesizing graphene directly onto our final device substrates. Using this method we have managed to fabricate large uniform arrays of graphene field effect transistors (GFETs) and are currently in the process of applying this method towards suspended devices as well as graphene membranes.

The reliable fabrication of single layer graphene over large areas will enable its use as a platform forming reliable interfaces to molecules, new materials, and even biological systems.

 

Optical tweezers are used to manipulate individual polymer microbeads functionalized with molecules of interest (DNA shown).  These technique provides information as to the location of the nanotube and the strength of the molecule - nanotube interaction.

We are also exploring the interface of nanotubes and graphene with single chemical and biological molecules, lipid membranes, and cells using a combination of electronic, physical, and optical approaches. The binding forces of individual molecules to a nanotube or graphene sheet are measured using optical tweezers in concert with sub-diffraction microscopy techniques. The interaction of cells with nanotubes and graphene is probed using nanomanipulators and confocal microscopy. These measurements have relevance for uses of carbon nanomaterials in therapeutics, sensing, and next-generation nanobiology.