University of California, Riverside

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Desalegne Teweldebrhan's Paper on Graphene Irradiation Highlighted in Media

Desalegne Teweldebrhan's Paper on Graphene Irradiation Highlighted in Media
Desalegne Teweldebrhan

Electrical engineering PhD graduate student Desalegne Teweldebrhan’s experimental research has led to an important result, which indicates graphene’s strong susceptibility to electron beam irradiation. Graphene is an allotrope of carbon, which consists of just a single atomic layer of carbon atoms. It is the newest “hottest” material system, which attracts tremendous attention Desalegne-NDL-09.jpgworld-wide. The latter is due to its unique properties such as extremely high electron mobility and thermal conductivity. There is a good chance that the next generation of ultra-high speed ICs will utilize graphene. Rather unexpectedly, Desalegne and his co-workers at Professor Balandin’s Nano-Device Laboratory (NDL) have found that even a short-time, few minutes, exposure of graphene to the low energy electron-beam irradiation results in substantial changes of graphene's properties. The Raman spectra of graphene, taken after each irradiation step, indicates that graphene transforms to the nano-crystalline, and then to the electrically insulating amorphous form. The results have important implications for graphene characterization and graphene device fabrication, which rely on the electron microscopy and focused ion beam processing. The irradiation dose required for changing graphene from electrical conductor to insulator is much smaller than that for carbon nanotubes due to graphene’s flat geometry, which makes it more susceptible to the electron flux. The finding of the UCR team is reported in the Applied Physics Letters and highlighted on the front page of NanoWerk, in the feature article at as well as in the Newsletter of the SRC- DARPA Center on Functional Engineered Nano Architectonics (FENA) at UCLA (see at

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