Response of free-standing graphene monolayer exposed to ultrashort intense XUV pulse from free-electron laser

Abstract

The response of a free-standing graphene monolayer exposed to a few tens of femtoseconds long extreme ultraviolet (XUV) pulse was studied theoretically in order to analyze and compare contributions of various mechanisms to the graphene damage, understood here as a global atomic disintegration. Our simulation results indicate that nonthermal disintegration of the atomic structure is the predominant damage mechanism for a free-standing graphene layer. Only at high absorbed doses, charge-induced disintegration of the graphene structure prevails. We also demonstrate that the progressing damage can be probed by femtosecond optical pulses in the soft UV regime (4 eV photon energy). The achieved quantitative understanding of the damage mechanisms may enable a better control of graphene-based devices when they are exposed to x-ray radiation, as well as an efficient processing of graphene layers with ultrashort intense XUV pulses.

Bond defects in graphene created by ultralow energy ion implantation

“…The self-assembled 1D defects that we observe with STM are likely to constitute the initial phase of formation of the grain boundaries between these interconnected nanocrystallites in disassembled graphene, which typically have characteristic length scales of the order of 10 nm, just like the typical separation between the self assembled 1D bond defects revealed by our STM data (figure 4). While for these lighter particles (electrons and photons), given the negligible kinetic-energy transfer to the C nuclei, the bond breaking is likely induced purely by electronic excitation [70] and ionization, in the present case (ions) it is plausible that both kinetic-energy transfer and electronic excitation/ionization play a role. Future studies, combining MD simulations and density functional theory (DFT) calculations [71], may provide further insight into these effects.…”