Mark Hersam is a materials scientist investigating the physical, chemical, and biological properties of nanomaterials with potential uses in a range of fields, including information technology, biotechnology, and energy. Taking an interdisciplinary approach that draws on techniques from materials science, physics, engineering, and chemistry, Hersam has established himself as a leading experimentalist in the area of hybrid organic-inorganic materials, with a focus on the study of the electrical and optical properties of carbon and related nanomaterials.
Graphene, a single atomic layer of hexagonally bonded carbon atoms, and carbon nanotubes, rolled sheets of graphene in single or multiple layers, have long been recognized for their potential applications in electronics, photovoltaics, batteries, and bioimaging. A limiting factor, however, has been the inability to separate carbon nanotubes efficiently based on characteristics such as electronic type, diameter, or chirality. The electrical properties of these materials are dependent on their physical and electronic structure, but when synthesized by conventional methods the different types of tubes are inextricably mixed together. Hersam developed a scalable, tunable solution to carbon nanotube separation based on a traditional biological research technique known as density gradient ultracentrifugation (DGU). Using this technique, Hersam is able to produce high-purity samples on a large scale, offering new promise for applied uses. For example, his lab recently demonstrated that semiconducting single-walled carbon nanotubes are promising candidates for next-generation electronics and photovoltaics.
Hersam has also developed and used sophisticated scanning tunneling microscope systems for studying fundamental aspects of surface properties at the atomic scale, in particular how various molecules interact with graphene. A dedicated teacher in addition to being a highly productive researcher, Hersam’s versatility and interdisciplinary approach are leading to path-breaking discoveries in the exploration, synthesis, and application of novel electronic materials.
Mark Hersam received a B.S. (1996) and Ph.D. (2000) from the University of Illinois at Urbana-Champaign and an M.Phil. (1997) from the University of Cambridge. In 2000, he joined the faculty of Northwestern University, where he is a professor in the Departments of Materials Science and Engineering, Chemistry, and Medicine and director of the Materials Research Science and Engineering Center. He also holds the Bette and Neison Harris Chair in Teaching Excellence. His research has been published in such journals as Nature Nanotechnology, Advanced Materials, Nano Letters, and ACS Nano.