Energy dissipation and defect generation in nanocrystalline silicon carbide

Journal Article · Sat May 01 00:00:00 EDT 2010 · Physical Review. B, Condensed Matter and Materials Physics

DOI:https://doi.org/10.1103/PHYSREVB.81.184101· OSTI ID:21366817

Gao, F; Weber, W J ^[1]; Chen, D ^[1]; Wangyu, Hu ^[2]

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1. Pacific Northwest National Laboratory, MS K8-93, P.O. Box 999, Richland, Washington 99352 (United States)
2. Department of Applied Physics, Hunan University, Changsha 410082 (China)

Large-scale molecular-dynamics simulations have been employed to study defect generation and primary damage state in nanocrystalline (NC) SiC of average grain diameters from 5 to 21 nm. Primary knock-on atom (PKA) kinetic energies of 10 keV are simulated and cascade structures in NC SiC with a grain size smaller than 12 nm are generally different from those generated in single-crystalline SiC. It is found that the local stresses near the grain boundaries (GBs) strongly affect the behavior of the PKA and secondary recoil atoms (SRAs), and the GBs act as sinks for deposition of kinetic energy. A striking feature is that the PKA and SRAs preferentially deposit energy along the GBs for grains with average size less 12 nm, which results in atomic displacements primarily within the GBs; whereas for larger grain sizes, most defects are produced within the grains. The defect production within gains generally increases with increasing grain size, which is manifested in switching from grain boundary damage to grain damage. The most common defects created in NC SiC are antisite defects, following by vacancies and interstitials, in contrast to those produced in a single-crystalline SiC, where the dominate defects are Frenkel pairs. Defect production efficiency increases with increasing grain size, with a typical value of 0.18 for small grains and rising to 0.5 for larger grains.

• OSTI ID: 21366817
• Journal Information: Physical Review. B, Condensed Matter and Materials Physics, Vol. 81, Issue 18; Other Information: DOI: 10.1103/PhysRevB.81.184101; (c) 2010 The American Physical Society; ISSN 1098-0121
• Country of Publication: United States
• Language: English

Related Subjects

77 NANOSCIENCE AND NANOTECHNOLOGY
ATOMIC DISPLACEMENTS
CRYSTAL DEFECTS
DEPOSITION
EFFICIENCY
ENERGY LOSSES
GRAIN BOUNDARIES
GRAIN SIZE
INTERSTITIALS
KEV RANGE 01-10
KINETIC ENERGY
KNOCK-ON
MOLECULAR DYNAMICS METHOD
MONOCRYSTALS
NANOSTRUCTURES
SILICON CARBIDES
SIMULATION
STRESSES
VACANCIES
CALCULATION METHODS
CARBIDES
CARBON COMPOUNDS
CRYSTAL STRUCTURE
CRYSTALS
ENERGY
ENERGY RANGE
KEV RANGE
LOSSES
MICROSTRUCTURE
PHYSICAL RADIATION EFFECTS
POINT DEFECTS
RADIATION EFFECTS
SILICON COMPOUNDS
SIZE