Joel Fridmann

Drawing graphene nanoribbons on SiC by ion implantation

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.

Low-temperature, site selective graphitization of SiC via ion implantation and pulsed laser annealing

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.

Multispecies focused ion beam lithography system and its applications

The authors present a focused ion beam lithography (IBL) instrument and its extension toward using different ion species beyond gallium. The base instrument utilizes a lithography architecture and an ion source and column dedicated to nanofabrication. This includes large area navigation and patterning by a laser interferometer stage, long-term beam to sample positional as well as beam current stability and automation capabilities. Since the ion type can have dramatic consequences on the resulting nanostructures, the authors have extended the gallium IBL tools ion column and source toward the stable delivery of multiple species for a nanometer scale focused ion beam based on a liquid metal alloy ion source. The IBL system is equipped with an E × B mass filter capable of selecting different single and multiple charged ion species, simultaneously originating from the same source. The authors investigated different AuSi or AuGe based sources and in particular an ion source delivering Au, Si and Be focused io...

First Results From A Multi-Ion Beam Lithography And Processing System At The University Of Florida

The University of Florida (UF) have collaborated with Raith to develop a version of the Raith ionLiNE IBL system that has the capability to deliver multi‐ion species in addition to the Ga ions normally available. The UF system is currently equipped with a AuSi liquid metal alloy ion source (LMAIS) and ExB filter making it capable of delivering Au and Si ions and ion clusters for ion beam processing. Other LMAIS systems could be developed in the future to deliver other ion species. This system is capable of high performance ion beam lithography, sputter profiling, maskless ion implantation, ion beam mixing, and spatial and temporal ion beam assisted writing and processing over large areas (100 mm2)—all with selected ion species at voltages from 15–40 kV and nanometer precision. We discuss the performance of the system with the AuSi LMAIS source and ExB mass separator. We report on initial results from the basic system characterization, ion beam lithography, as well as for basic ion‐solid interactions.

Synthesis of graphene and graphene nanostructures by ion implantation and pulsed laser annealing

In this paper, we report a systematic study that shows how the numerous processing parameters associated with ion implantation (II) and pulsed laser annealing (PLA) can be manipulated to control the quantity and quality of graphene (G), few-layer graphene (FLG), and other carbon nanostructures selectively synthesized in crystalline SiC (c-SiC). Controlled implantations of Si− plus C− and Au+ ions in c-SiC showed that both the thickness of the amorphous layer formed by ion damage and the doping effect of the implanted Au enhance the formation of G and FLG during PLA. The relative contributions of the amorphous and doping effects were studied separately, and thermal simulation calculations were used to estimate surface temperatures and to help understand the phase changes occurring during PLA. In addition to the amorphous layer thickness and catalytic doping effects, other enhancement effects were found to depend on other ion species, the annealing environment, PLA fluence and number of pulses, and even las...