Real-Time Optical Diagnostics of Rapid Graphene Growth CNMS Staff Science Highlight Real-time Raman spectroscopy, optical reflectivity, and microscope videography combined with pulsed gas introduction during chemical vapor deposition (CVD) were developed to characterize rapid isothermal graphene growth and subsequent precipitation upon cooling on catalytic substrates. The ability to observe 2D nanosheet growth at high temperatures enables growth kinetics measurements vs. processing conditions (e.g., flux, pressure, temperature, etc.) allowing fundamental growth understanding and forming the basis for remote diagnostics for advanced nanomanufacturing. • CNMS tunable-wavelength Raman system operating in the UV was employed to perform in situ Raman measurements at high temperatures within a specially-modified micro-CVD reactor. • Temperature dependent shifts, bandwidths, and intensities of the graphene G and 2D Raman bands were used to verify graphene growth, and estimate the fractional precipitation during cooling (with 1-second temporal resolution). • Optical reflectivity and videography were correlated with the Raman measurements to provide much faster diagnostics of the nucleation and growth kinetics of graphene. A. A. Puretzky, D. B. Geohegan, S. Pannala, C. M. Rouleau, M. Regmi, N. Thonnard and G. Eres , Nanoscale (2013). DOI:10.1039/c3nr01436c. Scientific Achievement Significance Research Details Schematic of the experimental setup. (a) UV excitation (l ex =405 nm) permits Raman spectra of graphene at high temperatures to be measured during isothermal growth (> 1s resolution) and subsequently by cooling, showing characteristic G and 2D bands. (b) Integrated intensities of the G- and 2D-Raman bands measured during cooling from the growth temperature (840 C° to room temperature reveal the fractional graphene precipitation upon cooling. Comparison of graphene growth kinetics measured after exposure to a single acetylene pulse using Raman scattering and reflectivity showing validity of the fast reflectivity approach for kinetic measurements Work was performed at the CNMS - ORNL