Johnson currently serves as the founding executive editor of the scientific journal AIP Advances and the co-founder of Graphene Frontiers, LLC.
His work specifically involves the transport within nanostructures and carbon nanotubes, which revolves around graphene, DNA, synthetic proteins, and other biomolecules.
[citation needed] His 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.
Johnson has made multiple contributions to the field,[citation needed] including pioneering the concept of feedback-controlled electromigration, an atomically precise fabrication technique for nanogap contacts in molecular electronic.
[citation needed] Johnson's work has also entailed a rigorous quantitative comparison between experimental data and all-atom Molecular Dynamics simulations.
Among Johnson's accomplishments is the formulation of a comprehensive theory of Scanning Conductance Microscopy, accompanied by a direct measurement of the dielectric constant of a polymer nanowire.
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.
Johnson's contributions extend to the development of "nanogap" electrical contacts for molecular electronic circuits, securing a patent for this technology.
[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.