His research focuses on atomic scale structure and properties of surfaces and nanomaterials for applications in electronics, catalysis, tribology and environmental science. He has developed novel instrumentation for studies of surface related phenomena, including High Pressure Scanning Tunneling Microscopy for catalysis studies, Scanning Polarization Force Microscopy for studies of liquid films and Ambient Pressure Photoelectron Spectroscopy for Environmental and Catalysis studies.
He was elected Fellow of the American Physical Society in 1996 and Fellow of the American Vacuum Society in 2003. He received the Outstanding Scientific Accomplishment Award in Materials Chemistry in 1995, and the Outstanding Research Award in 1996 from the U.S. Department of Energy. In 2004 he received the Klaus Halbach Award for the development of innovative instrumentation at the Advanced Light Source. In 2008 he received the Medard Welch Award of the American Vacuum Society and the Langmuir Lectureship Award of the American Chemical Society. In 2010 he received the R&D 100 Award of R&D Magazine. In 2012 he received the MRS Medal Award. In 2015 he received the APS Davisson-Germer Prize in Atomic or Surface Physics