A.T. Charlie Johnson

In 1994, Johnson began working at the University of Pennsylvania in the School of Arts and Sciences. He was promoted from assistant professor to associate professor in 2001. In 2002, Johnson received two secondary appointments in the School of Engineering: an appointment in electrical and systems engineering and an appointment in materials science and engineering. In 2008, he received a full professorship. Johnson served as the associate chair for undergraduate affairs from 2005 to 2011. Since 2011, he has been the associate chair of graduate affairs.[6]

Since he began working at Penn, Johnson has taught both undergraduate and graduate-level courses. These courses range from introductory physics to advanced statistical mechanics and thermodynamics.[6]

Johnson has been a leading researcher at Penn since he began working there in 1994. Prof. Johnson's research focuses on investigating transport phenomena (including charge, energy, and spin) in nanoscale systems such as carbon nanotubes and graphene, along with hybrid nanostructures that incorporate proteins, synthetic peptides, and DNA. Notable recent achievements in Prof. Johnson's research include the development of bio-inspired vapor sensors utilizing carbon nanotube transistors functionalized with mammalian olfactory receptors, the advancement of crystallographic etching techniques for graphene, and the successful large-scale production of graphene oxide membranes.

Prof. Johnson has made significant contributions to the field, including pioneering the concept of Feedback Controlled Electromigration, an atomically precise fabrication technique for nanogap contacts in molecular electronics that is currently pending patent. Additionally, Prof. Johnson has invented a DNA/nanotube gas sensor suitable for electronic nose systems, securing a patent for this innovation. Prof. Johnson's work has also entailed a rigorous quantitative comparison between experimental data and all-atom Molecular Dynamics simulations.

Among Prof. Johnson's accomplishments is the formulation of a comprehensive theory of Scanning Conductance Microscopy, accompanied by a groundbreaking direct measurement of the dielectric constant of a polymer nanowire. Prof. Johnson's research extends to the quantitative characterization of individual defects in nanotube devices, the creation of air-stable, n-type nanotube field-effect transistors, and the design and realization of nanotube memory cells. Prof. Johnson's work includes the exploration and control of Schottky barriers in carbon nanotube field-effect transistors via Scanning Gate Microscopy. Johnson has also achieved significant advancements in nanoscale devices, such as fabricating 20nm channel nanotube field-effect transistors and quantum dots. Prof. Johnson's groundbreaking discoveries include identifying 1-dimensional quantized phonon subbands in nanotubes. Additionally, Prof. Johnson has pioneered the production of nanotube-epoxy composite materials for thermal management, a technology currently under patent review. Finally, Prof. Johnson's contributions extend to the development of "nanogap" electrical contacts for molecular electronic circuits, securing a patent for this technology.[6] Johnson has received over 25 grants for his research, given 97 talks related to his work, and supervised over 120 students in conducting research. He has been an author or co-author on over 140 papers,[7] and received 9 patents.[6]

As Director of the Nano/Bio Interface Center at Penn, Johnson oversees all research conducted therein but is the principal investigator for the Biomolecular Optoelectronic Function project. This project is aimed at using organic and inorganic nanostructures to control energy transfer between various pieces of nanotechnology. One of the goals of the project is to interface biological and nanotechnological structures to create new materials that may have wide-ranging biological and medical applications. The team has created a novel approach to fabricating certain nanostructures, which has allowed the research to proceed successfully since it began.[8]

Johnson also founded and leads the Charlie Johnson Group, aimed at Experimental Nanoscale Physics. As the principal investigator, Johnson leads the four ongoing research projects, which are Molecular Electronics, Local Probes of Nanoscale Systems, Chemical and Biological Sensing, and Nanotube and Nanowire Electronics.[9] Among his assistant researchers are postdoctoral fellows, graduate students, and undergraduate students.

Johnson co-founded Graphene Frontiers, LLC through the UPStarts program in 2010. The company was selected for the National Science Foundation I-Corps program in 2011 and received an NSF SBIR grant in 2012.[6] Graphene Frontiers is one of the leading graphene manufacturers in the world, using novel techniques to create the one-atom-thick sheet.[10]

Johnson also co-founded Adamant Technologies, which is a start-up aimed at personalizing the healthcare industry, which was started as part of the Johnson Group.[6] The company, based out of San Francisco, has "developed a novel mobile chemical sensor device that allows users to track their health and fitness through chemicals in their breath."[11] The company is currently working on a related smartphone application.

Johnson is the Founding Executive Editor of AIP Advances, a peer-reviewed journal published by the American Institute of Physics.[12]