In 1995 Stephan was a visiting scientist at DuPont's Central Research and Development Laboratory in Wilmington, DE. Stephan Joined NIST in 1996 as a Research Chemist in the Chemical Science and Technology Laboratory. His research focuses on the development of nanoscale probes of surface physiochemical properties. He has published approximately 100 papers on the subject and has been awarded sixteen patents associated with microscopies for chemical and electrical characterization. Stephan's awards include the American Chemical Society's Nobel Laureate Signature Award, the American Chemical Society's Procter&Gamble Award in Physical Chemistry, the American Chemical Society's Arthur F. Findeis Award for Achievement by a Young Analytical Scientist, a BF Goodrich Inventors Award, the Union Carbide Kenan Analytical Award, the Xerox President's Award in Materials Research, the Samuel Wesley Stratton Award for Excellence in Science and Engineering, and the Department of Commerce Bronze Medal Award for Superior Federal Service.