Alan T. Charlie Johnson, Jr.

Research in our group is in the broad area of novel transport phenomena (charge, energy, spin, &c.) in graphene, nanotubes, nanowires, carbon nanotube hybrids (C60@SWNT; DNA-NT, protein-NT), and single molecules. We are interested in both the fundamental science of these systems and potential applications such as nose-like vapor sensing based on DNA-NT, and electronics beyond CMOS. Core lab activities include nanostructure synthesis, device design and fabrication, and conventional variable temperature magneto-transport measurements. In the pursuit of the group’s science goals, we have been involved in the development of new methods of scanning probe microscopy for measuring local electronic properties of nanomaterials and active nanodevices with nanoscale spatial resolution. We complement our experimental investigations on nanotube hybrids with classical all-atom molecular dynamics simulations, a collaboration with Michael Klein (Penn Chemistry).

Group interests range from fundamental explorations of materials physics at this scale to promising medium-term applications such as ultrasensitive nose-like detection of vapor phase analytes. Research projects involve nanostructures fabricated both from the "top-down" (by a wide variety of patterning techniques including electron beam lithography), and "bottom-up" (created via chemical vapor deposition or a chemical reaction). Experimental techniques in the lab include low-noise (magneto)transport at temperatures ranging from 100 millikelvin to 300 C, thermal transport measurements, and various scanned probe technologies, including Scanning Tunneling Microscopy (STM), Atomic Force Microscopy (AFM), and hybrid conducting-tip AFM (“electrostatic force microscopy” and other variants). We also use high performance computing systems to conduct all-atom Molecular Dynamics simulations that complement conventional microscopies.

The group is affiliated with several Centers on campus and in the region, including the Nano/Bio Interface Center (NSF-NSEC), the Laboratory for Research on the Structure of Matter (NSF-MRSEC), Institute for Medicine and Engineering, and the Pennsylvania Nanotechnology Institute. We have active collaborations with colleagues at the Monell Chemical Senses Center, and the Fox Chase Cancer Center. We are always looking for talented scientists to participate in the group as Postdoctoral Fellows, Graduate Research Assistants, and Undergraduate Researchers.

For more information and current publications, see our group web page here.

• Dean's Award for Mentorship of Undergraduate Research (2011)
• Christian R. and Mary F. Lindback Foundation Award for distinguished teaching at Penn (2003)
• Jack Raper Outstanding Technology Directions Paper Award, International Solid State Circuit Conference (1999)
• Alfred P. Sloan Research Fellow (1995)
• David and Lucille Packard Science and Engineering Fellow (1994)
• National Research Council Postdoctoral Fellow, 1992 -1993
• National Science Foundation Graduate Fellow (1984-87)

• Associate Professor of Physics, University of Pennsylvania (2001-)
• At University of Pennsylvania since 1994
• National Research Council Postdoctoral Fellow, National Institute for Standards and Technology (1992-93)
• ESPRIT Postdoctoral Fellow, Delft University of Technology (1990-92)

• Y. Lu, C.A. Merchant, M. Drndic, and A.T. Charlie Johnson, In-situ characterization of graphene nanoconstrictions fabricated in a transmission electron microscope, to appear in Nano Letters (2011).
• Brett Goldsmith, Joseph J. Mitala, Jr., Jesusa Josue, Ana Castro, Mitchell B. Lerner, Timothy H. Bayburt, Samuel M. Khamis, Ryan A. Jones, Joseph G. Brand, Stephen G. Sligar, Charles W. Luetje, Alan Gelperin, Paul A. Rhodes, Bohdana Discher, A.T. Charlie Johnson, Biomimetic chemical sensors based on carbon nanotube transistors functionalized with olfactory receptor proteins, ACS Nano 5, 5408-5416 (2011).
• Z. Luo, Y. Lu, D.W. Singer,* M.E. Berck,* L.A. Somers, B.R. Goldsmith, and A.T. Charlie Johnson, Effect of Substrate Roughness and Feedstock Concentration on Growth of Wafer-Scale Graphene at Atmospheric Pressure, Chemistry of Materials 23, 1441 – 1447 (2011).
• Y. Lu, B.R. Goldsmith, D.R. Strachan, J. Lim*, Z. Luo, A.T. Charlie Johnson, Graphene nanoconstriction field effect transistor, Small 23, 2748 – 2754 (2010).
• Christopher Merchant, Ken Healey, Meni Wanunu, Vishva Ray, Neil Peterman,* John Bartel,* Michael Fischbein, Kimberly Venta, Zhengtang Luo, A.T. Charlie Johnson, and Marija Drndic, DNA translocation through graphene nanopores, Nano Letters 10, 2915 – 2921(2010).
• Robert R. Johnson, A.T. Charlie Johnson, Michael L. Klein, The Nature of DNA Base-Carbon Nanotube Interactions, Small 6, 31-34 (2010).
• Y. Dan, Y. Lu, N.J. Kybert*, Z. Luo, and A.T. Charlie Johnson, Intrinsic response of graphene vapor sensors, Nano Letters 9, 1472 – 1475 (2009).
• Z. Luo, Y. Lu, L.A. Somers, and A.T. Charlie Johnson, Preparation of macroscopic graphene oxide membranes, Journal of the American Chemical Society 131, 898 – 899 (2009).
• M.F. Islam, E. Rojas*, D.M. Bergey**, A.T. Johnson, and A.G. Yodh, High weight fraction surfactant solubilization of single-wall carbon nanotubes in water, NanoLetters 3, 269 – 273 (2003).
• D.J. Hornbaker, S.J. Kahng, S. Misra, B.W. Smith, A.T. Johnson, E.J. Mele, D.E. Luzzi, and A. Yazdani, Mapping the one-dimensional electronic states of nanoscopic peapods, Science 295, 828 - 831 (2002). This article was featured on the cover of Science, February 1, 2002.
• Marcus Freitag, Sergei V. Kalinin, Dawn A. Bonnell, and A.T. Johnson, Role of single defects in electronic transport through carbon nanotube field effect transistors, Physical Review Letters 89, 216801 (2002).
• M. Biercuk*, M.C. Llaguno, M. Radosavljevic, J.K. Hyun*, J.E. Fischer, and A.T. Johnson, Carbon nanotube composites for thermal management, Applied Physics Letters 80, 2767 – 2769 (2002).
• J. Hone, B. Batlogg, Z. Benes, A.T. Johnson, J.E. Fischer, "Quantized phonon spectrum of single-wall carbon nanotubes," Science 289 p.1730-1733 (2000).
• R.D. Antonov, A.T. Johnson, "Subband population in a single-wall carbon nanotube diode," Physical Review Letters 83, p.3274-6 (1999).

Patents:

• Patent filing - “Biomimetic Chemical Sensors Using Nanoelectronic Readout of Olfactory Receptors”. Docket Number W5587/UPN-5498. Provisional Application filed 6/2010.
• “Growth of Uniform Wafer-Size Graphene”. Provisional Application #61/372,589 filed 8/2010
• “Photolithographically Defined Contacts to Carbon Nanostructures”. Disclosure filed with Penn CTT Nov. 2008. Provisional U.S. Patent Application #61177768 files May 13, 2009
• Patent filing – “Single walled carbon nanotubes functionally adsorbed to biopolymers for use as chemical sensors”. Submitted July 2007. U.S. Patent Number 7,977,054 B2, issued July 12, 2011.
• Patent disclosure – “Functionalized carbon nanotubes for detection of viral proteins”. Disclosure submitted to Penn Center for Technology Transfer, April 3, 2007. With co-inventors from Brookhaven National Laboratory and Stony Brook University.
• Patent disclosure – “Parallel fabrication of controlled electromigrated nanogaps”. Disclosure submitted to Penn Center for Technology Transfer, Feb. 5, 2007.
• Patent filing – “DNA-decorated Carbon Nanotube Field Effect Transistors for Chemical and Biological Sensing. US Patent Application submitted March 29, 2006.
• Patent filing. “Fabrication of Nanotube-Resin Composites”. CTT has filed this patent with the U.S. Patent Office
• Patent Number 6/897,009– “Fabrication of Nanogap Electrical Contacts”. With M. Radosavljevic and Jacques Lefebvre. Issued 5/24/05.
• Patent Number 6/720,553. “Tip Calibration Standard and Method for Tip Calibration for Scanning Impedance Microscopy”. With D.A. Bonnell. Issued 4/13/04