Ion–solid interactions at the extremes of electronic energy loss: Examples for amorphous semiconductors and embedded nanostructures

Abstract

A selection of ion-solid interactions in the swift heavy-ion irradiation regime is reviewed. We consider the effects of electronic energy loss at tens of keV/nm on both bulk material and nanostructures embedded in a matrix. Specific examples include ion track formation at low ion fluences in bulk Si and Ge and porous layer formation at high ion fluences in bulk Ge. In addition, the intriguing shape and phase transformations observable at high ion fluences in Ge and metallic nanoparticles embedded in bulk SiO 2 are examined and compared. Experiment, modelling and simulation are combined synergistically as we seek fundamental atomistic insight into these unique yet poorly understood processes operative only at the extremes of electronic energy loss.

Effects of intermediate energy heavy‐ion irradiation on the microstructure of rutile TiO2 single crystal

“…Backman's results are noteworthy because they reveal that nuclear and electronic stopping exhibit a nonlinear synergy within the ion energy range of interest, resulting in a higher local defect density than would result from sequential evolution of atomic recoil processes and an inelastic thermal spike . The synergistic effects of nuclear and electronic stopping have been described in the intermediate ion energy range in several ceramic systems …”

“…75,76 The synergistic effects of nuclear and electronic stopping have been described in the intermediate ion energy range in several ceramic systems. [79][80][81][82] Although nuclear stopping is the dominant mechanism for defect creation for 3 MeV Nb ions, Backman's work implies that electronic stopping processes can also contribute to damage creation. This is consistent with the order-disorder morphology of the loops and their local surroundings in Region 2-loops are created primarily by nuclear stopping event, but the disordering may partly be associated with inelastic thermal spike-type electronic stopping.…”

Phase transformations inLn2O3materials irradiated with swift heavy ions

“…This highly transient, nanometric energy deposition can produce unique structural changes in insulating materials, including the formation of defects 7,8 , polymorphic phase transformations 9,10 , amorphization 11,12 , chemical decomposition 13,14 , and irreversible deformations 15,16 . These irradiation-induced modifications are useful for the engineering of nanostructures [17][18][19][20] , the tailoring of optoelectronic properties 21 , and the simulation of damage to materials from particles of similar mass and energy, such as nuclear fission fragments 22 and cosmic rays 23 .…”

Modeling of intense pulsed ion beam heated masked targets for extreme materials characterization

“…Local heating and electronic excitation on a nanometer scale can drive materials well above the melting point for a few picoseconds followed by very rapid cooling and quenching of the intense, ultrafast electronic excitation, 10,11 driving complex material dynamics such as track formation and defect annealing. 12,13 When combined with the external pressure, novel phases can be induced and stabilized 14 and color centers, such as nitrogen vacancy centers in diamond, can be formed locally and without the need for subsequent thermal annealing. 15 The other common scenario is to simply use a broad beam of intense ions.…”