Single‐Phase Filamentary Cellular Breakdown Via Laser‐Induced Solute Segregation

Abstract

Nanosecond melting and quenching of materials offers a pathway to novel structures with unusual properties. Impurity-rich silicon processed using nanosecond-pulsed-laser-melting is known to produce nanoscale features in a process referred to as "cellular breakdown" due to destabilization of the planar liquid/solid interface. Here, we apply atom probe tomography combined with electron microscopy to show that the morphology of cellular breakdown in these materials is significantly more complex than previously documented. We observe breakdown into a complex, branching filamentary structure topped by a few nm of a cell-like layer. Singlephase diamond cubic silicon highly supersaturated with at least 10% atomic Co and no detectable silicides is reported within these filaments. In addition, the unprecedented spatio-chemical accuracy of the atom probe allows us to investigate nanosecond formation dynamics of this 2 complex material. Previously-reported properties of these materials can now be reconsidered in light of their true composition, and this class of inhomogeneous metastable alloys in silicon can be explored with confidence.

Insulator-to-metal transition in vanadium supersaturated silicon: variable-range hopping and Kondo effect signatures

“…These nanoscale features referred to as cellular-breakdown [24,25] (due to the presence of surface features resembling cell walls in plants). In a recent work, the 3D structure and composition of Si cellular-breakdown structures formed in a similar material have been investigated using atom probe tomography technique [26]. In this work, it has been shown that these filamentary structures are formed by transition metals segregation regions with up to a 10 a / o in Si.…”

“…In this work, it has been shown that these filamentary structures are formed by transition metals segregation regions with up to a 10 a / o in Si. In any case, these structures resulted free of defects presenting no evidence of polycrystalline material neither the formation of silicides [26,27].…”

Observation of enhanced infrared absorption in silicon supersaturated with gold by pulsed laser melting of nanometer-thick gold films

“…At such concentrations, Au incorporation is unlikely to be substitutional in the lattice but could be localized in high concentrations in spatially inhomogeneous regions, as seen in cellular breakdown. 22 This has been observed in Si supersaturated with transition metals using PLM of ion-implanted 10 and metal filmcoated Si. 23 Thermal annealing at 400 C resulted in dramatic changes to the Raman spectra of the thicker Au-film samples.…”

Vanadium supersaturated silicon system: a theoretical and experimental approach

“…In this work, it has been shown that these filamentary structures are formed by segregation regions of transition metals with up to 10% of Si atomic density. However, these structures are free of silicides, and no evidence of polycrystalline material was observed [37,38].…”