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We describe a straightforward technique for selective graphene growth and nanoribbon production onto 4H- and 6H-SiC. The technique presented is as easy as ion implanting regions where graphene layers are desired followed by annealing to 100 °C below the graphitization temperature (TG) of SiC. We find that ion implantation of SiC lowers the TG, allowing selective graphene growth at temperatures below the TG of pristine SiC and above TG of implanted SiC. This results in an approach for patterning device structures ranging from a couple tens of nanometers to microns in size without using conventional lithography and chemical processing.

Measurements of the N = 28 isotones 42 Si, 43 P and 44 S using one-and two-proton knockout reactions from the radioactive beam nuclei 44 S and 46 Ar are reported. The knockout reaction cross sections for populating 42 Si and 43 P and a 184 keV γ-ray observed in 43 P establish that the d 3/2 and s 1/2 proton orbits are nearly degenerate in these nuclei and that there is a substantial Z = 14 subshell closure separating these two orbits from the d 5/2 orbit. The increase in the inclusive twoproton knockout cross section from 42 Si to 44 S demonstrates the importance of the availability of valence protons for determining the cross section. New calculations of the two-proton knockout reactions that include diffractive effects are presented. In addition, it is proposed that a search for the d 5/2 proton strength in 43 P via a higher statistics one-proton knockout experiment could help determine the size of the Z = 14 closure.

Excited states in 20 O were populated in the reaction 10 Be( 14 C,α) at Florida State University. Charged particles were detected with a particle telescope consisting of 4 annularly segmented Si surface barrier detectors and γ radiation was detected with the FSU γ detector array. Five new states were observed below 6 MeV from the α-γ and α-γ-γ coincidence data. Shell model calculations suggest that most of the newly observed states are core-excited 1p-1h excitations across the N = Z = 8 shell gap. Comparisons between experimental data and calculations for the neutron-rich O and F isotopes imply a steady reduction of the p-sd shell gap as neutrons are added.

A technique is presented to selectively graphitize regions of SiC by ion implantation and pulsed laser annealing (PLA). Nanoscale features are patterned over large areas by multi-ion beam lithography and subsequently converted to few-layer graphene via PLA in air. Graphitization occurs only where ions have been implanted and without elevating the temperature of the surrounding substrate. Samples were characterized using Raman spectroscopy, ion scattering/channeling, SEM, and AFM, from which the degree of graphitization was determined to vary with implantation species, damage and dose, laser fluence, and pulsing. Contrasting growth regimes and graphitization mechanisms during PLA are discussed.

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