Jason D Fowlkes

R & D Staff

Research InterestsEducationUniversity of Tennessee-Knoxville B. S. 1997 Materials Science & EngineeringUniversity of Tennessee-Knoxville M.S. 1999 Materials Science & EngineeringUniversity of Tennessee-Knoxville Ph.D. 2002 Materials Science & EngineeringProfessional Experience2007–present Research Staff Member, Center for Nanophase Materials Sciences, ORNL2004–2007 Research Assistant Professor, University of Tennessee-Knoxville 2003–2004 Postdoctoral Research Fellow, University of Tennessee-Knoxville Professional Activities, Honors, AwardsOrganizer, 3rd International Workshop on Focused Electron Bead Induced Processing, 2010 Microscopy & Microanalysis Invited Talk: “Electron Beam Induced Deposition: Experiments, Challenges and Nano–Based Applications,” Richmond, July, 2009 Microscopy & Microanalysis Invited Talk: “Electron Beam Induced Processing: Experimentation, Simulation and Applications,” Albuquerque, August 2008 Sigma Xi Scientific Presentation Competition Winner, 2002 Outstanding Graduate Student Materials Science and Engineering, 2002 Reviewer, ACS Nano; Small; Nanotechnology; Thin Solid Films Tau Beta Pi, Engineering Honors Society, 2002Professional Memberships:American Association for the Advancement of ScienceAmerican Chemical SocietyResearch Interests1. Charged Particle Beam-Induced, Direct-Write Deposition/EtchingNanoscale direct-write assembly methods, such as focused particle beam processing, require precise understanding and control of the relevant electron/ion–vapor precursor–solid interactions where energy beams on the order of 1–10 nm dictate the assembly/removal of material at the confluence of the particle beam, adsorbed precursor and substrate. We determine precursor–substrate interaction parameters relevant for the electron/ion beam induced deposition methods through a combination of experiments and simulations. Monte Carlo simulations of the electron–substrate interaction are combined with finite difference simulations of precursor–substrate interactions to unravel the parameters by fitting to experimental results.2. Self and Directed Assembly of Thin, Liquid Metallic FilmsPhysical vapor deposition combined with nanolithography methods are used to deposit metallic materials with highly non-equilibrium shapes. Capillary, inertial and viscous forces dictate the mass transport of the metal once liquefied. The initial shape of the metallic feature is used to harness liquid surface instabilities for the self assembly of metallic nanoparticles. Pulsed laser irradiation is used to liquefy the metal features where rapid heating and cooling rates and nanosecond melt lifetimes are achievable. Directed assembly is possible by imposing periodic fluctuations onto the initial metal geometry which translates into highly precise arrays of metallic nanoparticles/nanocaps.3. Solute Diffusion in Crowded EnvironmentsBiomolecular transport in cellular environments occurs in crowded surroundings where molecular reactivity and diffusion can be significantly altered when compared with dilute solution conditions. By the prescribed design of spatially restricted environments, micro- and nanofabrication techniques can be used to replicate specific features of such systems. We implement Monte Carlo, Brownian based simulation methods to design, and fabricate, micro- and nano- size containers and crowding features intended to control the reaction and diffusion of matter at biologically relevant length and time scales.

Publications